Various warnings resolved and TreatWarningsAsErrors enabled (#2409)

Directory.Build.props

@@ -0,0 +1,73 @@
+<Project>
+  <!-- 
+    Common build properties for all projects in the Radzen.Blazor solution.
+    
+    To use this file:
+    1. Rename to Directory.Build.props (remove .sample extension)
+    2. Adjust settings based on your needs
+    3. Review the analyzer settings in .editorconfig
+    
+    This file will be automatically imported by all projects in subdirectories.
+  -->
+
+  <PropertyGroup Label="Language Configuration">
+    <!-- Use latest C# language features -->
+    <LangVersion>latest</LangVersion>
+    
+    <!-- Do NOT enable implicit usings - explicit imports preferred for library code -->
+    <ImplicitUsings>disable</ImplicitUsings>
+    
+    <Nullable>enable</Nullable>
+    <NoWarn>CA2007</NoWarn>
+  </PropertyGroup>
+
+  <PropertyGroup Label="Code Analysis Configuration">
+    <!-- Enable .NET code analyzers -->
+    <AnalysisLevel>latest</AnalysisLevel>
+    <EnableNETAnalyzers>true</EnableNETAnalyzers>
+    
+    <!-- Run analyzers during build and in IDE -->
+    <RunAnalyzersDuringBuild>true</RunAnalyzersDuringBuild>
+    <RunAnalyzersDuringLiveAnalysis>true</RunAnalyzersDuringLiveAnalysis>
+    
+    <!-- Don't enforce code style in build (yet) - just show warnings -->
+    <EnforceCodeStyleInBuild>false</EnforceCodeStyleInBuild>
+    
+    <!-- Don't treat warnings as errors (yet) - too many to fix immediately -->
+    <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
+    
+    <!-- Report all analyzer diagnostics -->
+    <AnalysisMode>All</AnalysisMode>
+  </PropertyGroup>
+
+  <PropertyGroup Label="Build Quality">
+    <!-- Enable deterministic builds for reproducibility -->
+    <Deterministic>true</Deterministic>
+    
+    <!-- Enable deterministic builds in CI/CD -->
+    <ContinuousIntegrationBuild Condition="'$(CI)' == 'true'">true</ContinuousIntegrationBuild>
+    
+    <!-- Embed source files for better debugging -->
+    <EmbedAllSources>true</EmbedAllSources>
+    <DebugType>embedded</DebugType>
+  </PropertyGroup>
+
+  <PropertyGroup Label="Demos and Tests Project Configuration" Condition="$(MSBuildProjectName.Contains('Demos')) OR $(MSBuildProjectName.Contains('Tests'))">
+    <!-- Demo projects and Tests should not be packable -->
+    <IsPackable>false</IsPackable>
+    
+    <!-- DISABLE ALL ANALYZERS FOR DEMO PROJECTS AND TESTS -->
+    <EnableNETAnalyzers>false</EnableNETAnalyzers>
+    <RunAnalyzersDuringBuild>false</RunAnalyzersDuringBuild>
+    <RunAnalyzersDuringLiveAnalysis>false</RunAnalyzersDuringLiveAnalysis>
+    <EnforceCodeStyleInBuild>false</EnforceCodeStyleInBuild>
+  </PropertyGroup>
+
+  <PropertyGroup Label="Performance">
+    <!-- Optimize startup time -->
+    <TieredCompilation>true</TieredCompilation>
+    <TieredCompilationQuickJit>true</TieredCompilationQuickJit>
+  </PropertyGroup>
+
+</Project>
+

Radzen.Blazor.Tests/ExpressionSerializerTests.cs

@@ -22,7 +22,7 @@ namespace Radzen.Blazor.Tests
         public Guid Id { get; set; }
         public TimeOnly StartTime { get; set; }
         public DateOnly BirthDate { get; set; }
-        public List<int> Scores { get; set; }
+        public IEnumerable<int> Scores { get; set; }
         public List<string> Tags { get; set; }
         public List<TestEntity> Children { get; set; }
         public Address Address { get; set; }

Radzen.Blazor.Tests/PivotDataGridTests.cs

@@ -605,7 +605,7 @@ namespace Radzen.Blazor.Tests
             Assert.True(grid.AllowFieldsPicking);
         }
 
-        private static IRenderedComponent<RadzenPivotDataGrid<SalesData>> RenderPivotDataGrid(TestContext ctx, Action<ComponentParameterCollectionBuilder<RadzenPivotDataGrid<SalesData>>>? configure = null)
+        private static IRenderedComponent<RadzenPivotDataGrid<SalesData>> RenderPivotDataGrid(TestContext ctx, Action<ComponentParameterCollectionBuilder<RadzenPivotDataGrid<SalesData>>> configure = null)
         {
             return ctx.RenderComponent<RadzenPivotDataGrid<SalesData>>(parameters =>
             {

Radzen.Blazor.Tests/Radzen.Blazor.Tests.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <TargetFramework>net10.0</TargetFramework>
-
+    <Nullable>disable</Nullable>
     <IsPackable>false</IsPackable>
   </PropertyGroup>
 

Radzen.Blazor/.editorconfig

@@ -6,6 +6,48 @@ root = true
 
 #### Core EditorConfig Options ####
 
+dotnet_diagnostic.CA1002.severity = none
+dotnet_diagnostic.CA1003.severity = none
+dotnet_diagnostic.CA1024.severity = none
+dotnet_diagnostic.CA1030.severity = none
+dotnet_diagnostic.CA1031.severity = none
+dotnet_diagnostic.CA1033.severity = none
+dotnet_diagnostic.CA1044.severity = none
+dotnet_diagnostic.CA1050.severity = none
+dotnet_diagnostic.CA1051.severity = none
+dotnet_diagnostic.CA1052.severity = none
+dotnet_diagnostic.CA1054.severity = none
+dotnet_diagnostic.CA1055.severity = none
+dotnet_diagnostic.CA1056.severity = none
+dotnet_diagnostic.CA1063.severity = none
+dotnet_diagnostic.CA1068.severity = none
+dotnet_diagnostic.CA1308.severity = none
+dotnet_diagnostic.CA1708.severity = none
+dotnet_diagnostic.CA1711.severity = none
+dotnet_diagnostic.CA1716.severity = none
+dotnet_diagnostic.CA1720.severity = none
+dotnet_diagnostic.CA1721.severity = none
+dotnet_diagnostic.CA1724.severity = none
+dotnet_diagnostic.CA1725.severity = none
+dotnet_diagnostic.CA1802.severity = none
+dotnet_diagnostic.CA1814.severity = none
+dotnet_diagnostic.CA1815.severity = none
+dotnet_diagnostic.CA1816.severity = none
+dotnet_diagnostic.CA1819.severity = none
+dotnet_diagnostic.CA1822.severity = none
+dotnet_diagnostic.CA1827.severity = none
+dotnet_diagnostic.CA1834.severity = none
+dotnet_diagnostic.CA1845.severity = none
+dotnet_diagnostic.CA1849.severity = none
+dotnet_diagnostic.CA1851.severity = none
+dotnet_diagnostic.CA1859.severity = none
+dotnet_diagnostic.CA1863.severity = none
+dotnet_diagnostic.CA1869.severity = none
+dotnet_diagnostic.CA2007.severity = none
+dotnet_diagnostic.CA2012.severity = none
+dotnet_diagnostic.CA2211.severity = none
+dotnet_diagnostic.CA2227.severity = none
+
 # Indentation and spacing
 indent_size = 4
 indent_style = space

Radzen.Blazor/AIChatService.cs

@@ -21,13 +21,16 @@ public class AIChatService(IServiceProvider serviceProvider, IOptions<AIChatServ
     private readonly Dictionary<string, ConversationSession> sessions = new();
     private readonly object sessionsLock = new();
 
+    // Add this static field to cache the JsonSerializerOptions instance
+    private static readonly JsonSerializerOptions CachedJsonSerializerOptions = new JsonSerializerOptions { DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull };
+
     /// <summary>
     /// Gets the configuration options for the chat streaming service.
     /// </summary>
     public AIChatServiceOptions Options => options.Value;
 
     /// <inheritdoc />
-    public async IAsyncEnumerable<string> GetCompletionsAsync(string userInput, string sessionId = null, [System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken = default, string model = null, string systemPrompt = null, double? temperature = null, int? maxTokens = null, string endpoint = null, string proxy = null, string apiKey = null, string apiKeyHeader = null)
+    public async IAsyncEnumerable<string> GetCompletionsAsync(string userInput, string? sessionId = null, [System.Runtime.CompilerServices.EnumeratorCancellation] CancellationToken cancellationToken = default, string? model = null, string? systemPrompt = null, double? temperature = null, int? maxTokens = null, string? endpoint = null, string? proxy = null, string? apiKey = null, string? apiKeyHeader = null)
     {
         if (string.IsNullOrWhiteSpace(userInput))
         {
@@ -57,13 +60,18 @@ public class AIChatService(IServiceProvider serviceProvider, IOptions<AIChatServ
             stream = true
         };
 
-        var request = new HttpRequestMessage(HttpMethod.Post, url)
+        using var request = new HttpRequestMessage(HttpMethod.Post, url)
         {
-            Content = new StringContent(JsonSerializer.Serialize(payload, new JsonSerializerOptions { DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull }), Encoding.UTF8, "application/json")
+            Content = new StringContent(JsonSerializer.Serialize(payload, CachedJsonSerializerOptions), Encoding.UTF8, "application/json")
         };
 
         if (!string.IsNullOrEmpty(effectiveApiKey))
         {
+            if (string.IsNullOrWhiteSpace(effectiveApiKeyHeader))
+            {
+                throw new InvalidOperationException("API key header must be specified when an API key is provided.");
+            }
+
             if (string.Equals(effectiveApiKeyHeader, "Authorization", StringComparison.OrdinalIgnoreCase))
             {
                 request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", effectiveApiKey);
@@ -75,22 +83,22 @@ public class AIChatService(IServiceProvider serviceProvider, IOptions<AIChatServ
         }
 
         var httpClient = serviceProvider.GetRequiredService<HttpClient>();
-        var response = await httpClient.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, cancellationToken);
+        var response = await httpClient.SendAsync(request, HttpCompletionOption.ResponseHeadersRead, cancellationToken).ConfigureAwait(false);
 
         if (!response.IsSuccessStatusCode)
         {
-            throw new Exception($"Chat stream failed: {await response.Content.ReadAsStringAsync(cancellationToken)}");
+            throw new HttpRequestException($"Chat stream failed: {await response.Content.ReadAsStringAsync(cancellationToken).ConfigureAwait(false)}");
         }
 
-        using var stream = await response.Content.ReadAsStreamAsync(cancellationToken);
+        using var stream = await response.Content.ReadAsStreamAsync(cancellationToken).ConfigureAwait(false);
         using var reader = new StreamReader(stream);
 
         var assistantResponse = new StringBuilder();
 
-        string line;
+        string? line;
         while ((line = await reader.ReadLineAsync()) is not null && !cancellationToken.IsCancellationRequested)
         {
-            if (string.IsNullOrWhiteSpace(line) || !line.StartsWith("data:"))
+            if (string.IsNullOrWhiteSpace(line) || !line.StartsWith("data:", StringComparison.Ordinal))
             {
                 continue;
             }
@@ -118,7 +126,7 @@ public class AIChatService(IServiceProvider serviceProvider, IOptions<AIChatServ
     }
 
     /// <inheritdoc />
-    public ConversationSession GetOrCreateSession(string sessionId = null)
+    public ConversationSession GetOrCreateSession(string? sessionId = null)
     {
         lock (sessionsLock)
         {
@@ -182,9 +190,14 @@ public class AIChatService(IServiceProvider serviceProvider, IOptions<AIChatServ
 
     private static string ParseStreamingResponse(string json)
     {
+        if (string.IsNullOrWhiteSpace(json))
+        {
+            return string.Empty;
+        }
+
         try
         {
-            var doc = JsonDocument.Parse(json);
+            using var doc = JsonDocument.Parse(json);
             var root = doc.RootElement;
 
             if (!root.TryGetProperty("choices", out var choices) || choices.GetArrayLength() == 0)
@@ -206,7 +219,11 @@ public class AIChatService(IServiceProvider serviceProvider, IOptions<AIChatServ
 
             return string.Empty;
         }
-        catch
+        catch (JsonException)
+        {
+            return string.Empty;
+        }
+        catch (FormatException)
         {
             return string.Empty;
         }

Radzen.Blazor/AIChatServiceExtensions.cs

@@ -16,15 +16,8 @@ public static class AIChatServiceExtensions
     /// <returns>The updated service collection.</returns>
     public static IServiceCollection AddAIChatService(this IServiceCollection services, Action<AIChatServiceOptions> configureOptions)
     {
-        if (services == null)
-        {
-            throw new ArgumentNullException(nameof(services));
-        }
-
-        if (configureOptions == null)
-        {
-            throw new ArgumentNullException(nameof(configureOptions));
-        }
+        ArgumentNullException.ThrowIfNull(services);
+        ArgumentNullException.ThrowIfNull(configureOptions);
 
         services.Configure(configureOptions);
         services.AddScoped<IAIChatService, AIChatService>();

Radzen.Blazor/AIChatServiceOptions.cs

@@ -13,7 +13,7 @@ public class AIChatServiceOptions
     /// <summary>
     /// Gets or sets the proxy URL for the AI service, if any. If set, this will override the Endpoint.
     /// </summary>
-    public string Proxy { get; set; } = null;
+    public string? Proxy { get; set; }
 
     /// <summary>
     /// Gets or sets the API key for authentication with the AI service.
@@ -28,7 +28,7 @@ public class AIChatServiceOptions
     /// <summary>
     /// Gets or sets the model name to use for executing chat completions (e.g., 'gpt-3.5-turbo').
     /// </summary>
-    public string Model { get; set; }
+    public string? Model { get; set; }
 
     /// <summary>
     /// Gets or sets the system prompt for the AI assistant.

Radzen.Blazor/AppointmentData.cs

@@ -22,19 +22,19 @@ namespace Radzen.Blazor
         /// Gets or sets the text of the appointment.
         /// </summary>
         /// <value>The text.</value>
-        public string Text { get; set; }
+        public string? Text { get; set; }
         /// <summary>
         /// Gets or sets the data associated with the appointment
         /// </summary>
         /// <value>The data.</value>
-        public object Data { get; set; }
+        public object? Data { get; set; }
 
         /// <summary>
         /// Determines whether the specified object is equal to this instance. Used to check if two appointments are equal.
         /// </summary>
         /// <param name="obj">The object to compare with this instance.</param>
         /// <returns><c>true</c> if the specified is equal to this instance; otherwise, <c>false</c>.</returns>
-        public override bool Equals(object obj)
+        public override bool Equals(object? obj)
         {
             return obj is AppointmentData data &&
                    Start == data.Start &&

Radzen.Blazor/AxisBase.cs

@@ -13,7 +13,7 @@ namespace Radzen.Blazor
         /// </summary>
         /// <value>The stroke.</value>
         [Parameter]
-        public string Stroke { get; set; }
+        public string? Stroke { get; set; }
         /// <summary>
         /// Gets or sets the pixel width of axis.
         /// </summary>
@@ -26,21 +26,21 @@ namespace Radzen.Blazor
         /// </summary>
         /// <value>The child content.</value>
         [Parameter]
-        public RenderFragment ChildContent { get; set; }
+        public RenderFragment? ChildContent { get; set; }
 
         /// <summary>
         /// Gets or sets the format string used to display the axis values.
         /// </summary>
         /// <value>The format string.</value>
         [Parameter]
-        public string FormatString { get; set; }
+        public string? FormatString { get; set; }
 
         /// <summary>
         /// Gets or sets a formatter function that formats the axis values.
         /// </summary>
         /// <value>The formatter.</value>
         [Parameter]
-        public Func<object, string> Formatter { get; set; }
+        public Func<object, string>? Formatter { get; set; }
 
         /// <summary>
         /// Gets or sets the type of the line used to display the axis.
@@ -80,20 +80,20 @@ namespace Radzen.Blazor
         /// </summary>
         /// <value>The minimum.</value>
         [Parameter]
-        public object Min { get; set; }
+        public object? Min { get; set; }
 
         /// <summary>
         /// Specifies the maximum value of the axis.
         /// </summary>
         /// <value>The maximum.</value>
         [Parameter]
-        public object Max { get; set; }
+        public object? Max { get; set; }
 
         /// <summary>
         /// Specifies the step of the axis.
         /// </summary>
         [Parameter]
-        public object Step { get; set; }
+        public object? Step { get; set; }
 
         /// <summary>
         /// Gets or sets a value indicating whether this <see cref="AxisBase"/> is visible.
@@ -139,7 +139,7 @@ namespace Radzen.Blazor
             }
             else
             {
-                return scale.FormatTick(FormatString, value);
+                return scale.FormatTick(FormatString ?? string.Empty, value);
             }
         }
 

Radzen.Blazor/CartesianSeries.cs

@@ -19,7 +19,17 @@ namespace Radzen.Blazor
         /// Cache for the value returned by <see cref="Category"/> when that value is only dependent on
         /// <see cref="CategoryProperty"/>.
         /// </summary>
-        Func<TItem, double> categoryPropertyCache;
+        Func<TItem, double>? categoryPropertyCache;
+
+        /// <summary>
+        /// Returns the parent <see cref="RadzenChart"/> instance or throws an <see cref="InvalidOperationException"/> if not present.
+        /// </summary>
+        /// <returns>The parent <see cref="RadzenChart"/>.</returns>
+        /// <exception cref="InvalidOperationException">Thrown when the parent chart is not set.</exception>
+        protected RadzenChart RequireChart()
+        {
+            return Chart ?? throw new InvalidOperationException($"{GetType().Name} requires a parent RadzenChart.");
+        }
 
         /// <summary>
         /// Creates a getter function that returns a value from the specified category scale for the specified data item.
@@ -34,13 +44,13 @@ namespace Radzen.Blazor
 
             if (IsNumeric(CategoryProperty))
             {
-                categoryPropertyCache = PropertyAccess.Getter<TItem, double>(CategoryProperty);
+                categoryPropertyCache = PropertyAccess.Getter<TItem, double>(CategoryProperty!);
                 return categoryPropertyCache;
             }
 
             if (IsDate(CategoryProperty))
             {
-                var category = PropertyAccess.Getter<TItem, DateTime>(CategoryProperty);
+                var category = PropertyAccess.Getter<TItem, DateTime>(CategoryProperty!);
                 categoryPropertyCache = (item) => category(item).Ticks;
                 return categoryPropertyCache;
             }
@@ -49,7 +59,7 @@ namespace Radzen.Blazor
             {
                 Func<TItem, object> category = String.IsNullOrEmpty(CategoryProperty) ? (item) => string.Empty : PropertyAccess.Getter<TItem, object>(CategoryProperty);
 
-                return (item) => ordinal.Data.IndexOf(category(item));
+                return (item) => ordinal.Data?.IndexOf(category(item)) ?? -1;
             }
 
             return (item) => Items.IndexOf(item);
@@ -60,6 +70,8 @@ namespace Radzen.Blazor
         /// </summary>
         protected Func<TItem, double> ComposeCategory(ScaleBase scale)
         {
+            ArgumentNullException.ThrowIfNull(scale);
+
             return scale.Compose(Category(scale));
         }
 
@@ -68,6 +80,8 @@ namespace Radzen.Blazor
         /// </summary>
         protected Func<TItem, double> ComposeValue(ScaleBase scale)
         {
+            ArgumentNullException.ThrowIfNull(scale);
+
             return scale.Compose(Value);
         }
 
@@ -77,7 +91,7 @@ namespace Radzen.Blazor
         /// <param name="propertyName">Name of the property.</param>
         /// <returns><c>true</c> if the specified property name is date; otherwise, <c>false</c>.</returns>
         /// <exception cref="ArgumentException">Property {propertyName} does not exist</exception>
-        protected bool IsDate(string propertyName)
+        protected bool IsDate(string? propertyName)
         {
             if (String.IsNullOrEmpty(propertyName))
             {
@@ -106,7 +120,7 @@ namespace Radzen.Blazor
         /// <param name="propertyName">Name of the property.</param>
         /// <returns><c>true</c> if the specified property name is numeric; otherwise, <c>false</c>.</returns>
         /// <exception cref="ArgumentException">Property {propertyName} does not exist</exception>
-        protected bool IsNumeric(string propertyName)
+        protected bool IsNumeric(string? propertyName)
         {
             if (String.IsNullOrEmpty(propertyName))
             {
@@ -125,21 +139,21 @@ namespace Radzen.Blazor
 
         /// <inheritdoc />
         [Parameter]
-        public string Title { get; set; }
+        public string Title { get; set; } = null!;
 
         /// <summary>
         /// Gets or sets the child content.
         /// </summary>
         /// <value>The child content.</value>
         [Parameter]
-        public RenderFragment ChildContent { get; set; }
+        public RenderFragment? ChildContent { get; set; }
 
         /// <summary>
         /// Gets or sets the tooltip template.
         /// </summary>
         /// <value>The tooltip template.</value>
         [Parameter]
-        public RenderFragment<TItem> TooltipTemplate { get; set; }
+        public RenderFragment<TItem>? TooltipTemplate { get; set; }
 
         /// <summary>
         /// Gets the list of overlays.
@@ -157,7 +171,7 @@ namespace Radzen.Blazor
         /// The name of the property of <typeparamref name="TItem" /> that provides the X axis (a.k.a. category axis) values.
         /// </summary>
         [Parameter]
-        public string CategoryProperty { get; set; }
+        public string? CategoryProperty { get; set; }
 
         /// <summary>
         /// Gets or sets a value indicating whether this <see cref="CartesianSeries{TItem}"/> is visible.
@@ -194,7 +208,7 @@ namespace Radzen.Blazor
         /// The name of the property of <typeparamref name="TItem" /> that provides the Y axis (a.k.a. value axis) values.
         /// </summary>
         [Parameter]
-        public string ValueProperty { get; set; }
+        public string? ValueProperty { get; set; }
 
         /// <inheritdoc />
         [Parameter]
@@ -223,7 +237,7 @@ namespace Radzen.Blazor
         /// </summary>
         /// <value>The data.</value>
         [Parameter]
-        public IEnumerable<TItem> Data { get; set; }
+        public IEnumerable<TItem>? Data { get; set; }
 
         /// <summary>
         /// Stores <see cref="Data" /> as an IList of <typeparamref name="TItem"/>.
@@ -272,6 +286,8 @@ namespace Radzen.Blazor
         /// <inheritdoc />
         public virtual ScaleBase TransformCategoryScale(ScaleBase scale)
         {
+            ArgumentNullException.ThrowIfNull(scale);
+
             if (Items == null)
             {
                 return scale;
@@ -298,7 +314,7 @@ namespace Radzen.Blazor
 
             var data = GetCategories();
 
-            if (scale is OrdinalScale ordinal)
+            if (scale is OrdinalScale ordinal && ordinal.Data != null)
             {
                 foreach (var item in ordinal.Data)
                 {
@@ -328,6 +344,8 @@ namespace Radzen.Blazor
         /// <inheritdoc />
         public virtual ScaleBase TransformValueScale(ScaleBase scale)
         {
+            ArgumentNullException.ThrowIfNull(scale);
+
             if (Items != null)
             {
                 if (Items.Any())
@@ -398,29 +416,32 @@ namespace Radzen.Blazor
             {
                 if (Data != null)
                 {
-                    if (Data is IList<TItem>)
+                    if (Data is IList<TItem> list)
                     {
-                        Items = Data as IList<TItem>;
+                        Items = list;
                     }
                     else
                     {
                         Items = Data.ToList();
                     }
 
-                    if (IsDate(CategoryProperty) || IsNumeric(CategoryProperty))
+                    if (!string.IsNullOrEmpty(CategoryProperty) && (IsDate(CategoryProperty) || IsNumeric(CategoryProperty)))
                     {
                         Items = Items.AsQueryable().OrderBy(CategoryProperty).ToList();
                     }
                 }
 
-                await Chart.Refresh(false);
+                if (Chart != null)
+                {
+                    await Chart.Refresh(false);
+                }
             }
         }
 
         /// <inheritdoc />
         protected override void Initialize()
         {
-            Chart.AddSeries(this);
+            Chart?.AddSeries(this);
         }
 
         /// <inheritdoc />
@@ -443,6 +464,9 @@ namespace Radzen.Blazor
         /// <returns><c>true</c> if the polygon contains the point, <c>false</c> otherwise.</returns>
         protected bool InsidePolygon(Point point, Point[] polygon)
         {
+            ArgumentNullException.ThrowIfNull(point);
+            ArgumentNullException.ThrowIfNull(polygon);
+
             var minX = polygon[0].X;
             var maxX = polygon[0].X;
             var minY = polygon[0].Y;
@@ -479,18 +503,22 @@ namespace Radzen.Blazor
         /// <inheritdoc />
         public virtual RenderFragment RenderTooltip(object data)
         {
+            var chart = RequireChart();
             var item = (TItem)data;
-            
+
             return builder =>
             {
-                if (Chart.Tooltip.Shared)
+                if (chart.Tooltip.Shared)
                 {
-                    var category = PropertyAccess.GetValue(item, CategoryProperty);
-                    builder.OpenComponent<ChartSharedTooltip>(0);
-                    builder.AddAttribute(1, nameof(ChartSharedTooltip.Class), TooltipClass(item));
-                    builder.AddAttribute(2, nameof(ChartSharedTooltip.Title), TooltipTitle(item));
-                    builder.AddAttribute(3, nameof(ChartSharedTooltip.ChildContent), RenderSharedTooltipItems(category));
-                    builder.CloseComponent();
+                    var category = !string.IsNullOrEmpty(CategoryProperty) ? PropertyAccess.GetValue(item, CategoryProperty) : null;
+                    if (category != null)
+                    {
+                        builder.OpenComponent<ChartSharedTooltip>(0);
+                        builder.AddAttribute(1, nameof(ChartSharedTooltip.Class), TooltipClass(item));
+                        builder.AddAttribute(2, nameof(ChartSharedTooltip.Title), TooltipTitle(item));
+                        builder.AddAttribute(3, nameof(ChartSharedTooltip.ChildContent), RenderSharedTooltipItems(category));
+                        builder.CloseComponent();
+                    }
                 }
                 else
                 {
@@ -508,9 +536,11 @@ namespace Radzen.Blazor
 
         private RenderFragment RenderSharedTooltipItems(object category)
         {
+            var chart = RequireChart();
+
             return builder =>
             {
-                var visibleSeries = Chart.Series.Where(s => s.Visible).ToList();
+                var visibleSeries = chart.Series.Where(s => s.Visible).ToList();
 
                 foreach (var series in visibleSeries)
                 {
@@ -524,7 +554,7 @@ namespace Radzen.Blazor
         {
             return builder =>
             {
-                var item = Items.FirstOrDefault(i => object.Equals(PropertyAccess.GetValue(i, CategoryProperty), category));
+                var item = Items.FirstOrDefault(i => !string.IsNullOrEmpty(CategoryProperty) && object.Equals(PropertyAccess.GetValue(i, CategoryProperty), category));
 
                 if (item != null)
                 {
@@ -553,7 +583,7 @@ namespace Radzen.Blazor
         /// <param name="item">The item.</param>
         protected virtual string TooltipStyle(TItem item)
         {
-            return Chart.Tooltip.Style;
+            return Chart?.Tooltip?.Style ?? string.Empty;
         }
 
         /// <summary>
@@ -562,7 +592,13 @@ namespace Radzen.Blazor
         /// <param name="item">The item.</param>
         protected virtual string TooltipClass(TItem item)
         {
-            return $"rz-series-{Chart.Series.IndexOf(this)}-tooltip";
+            var chart = Chart;
+            if (chart == null)
+            {
+                return "rz-series-tooltip";
+            }
+
+            return $"rz-series-{chart.Series.IndexOf(this)}-tooltip";
         }
 
         /// <inheritdoc />
@@ -576,6 +612,8 @@ namespace Radzen.Blazor
         /// </summary>
         protected virtual RenderFragment RenderLegendItem(bool clickable)
         {
+            var chart = RequireChart();
+            var index = chart.Series.IndexOf(this);
             var style = new List<string>();
 
             if (IsVisible == false)
@@ -586,7 +624,7 @@ namespace Radzen.Blazor
             return builder =>
             {
                 builder.OpenComponent<LegendItem>(0);
-                builder.AddAttribute(1, nameof(LegendItem.Index), Chart.Series.IndexOf(this));
+                builder.AddAttribute(1, nameof(LegendItem.Index), index);
                 builder.AddAttribute(2, nameof(LegendItem.Color), Color);
                 builder.AddAttribute(3, nameof(LegendItem.MarkerType), MarkerType);
                 builder.AddAttribute(4, nameof(LegendItem.Style), string.Join(";", style));
@@ -617,19 +655,35 @@ namespace Radzen.Blazor
         /// <inheritdoc />
         public double GetMedian()
         {
-            return Data.Select(e => Value(e)).OrderBy(e => e).Skip(Data.Count() / 2).FirstOrDefault();
+            var values = Items.Select(Value).OrderBy(e => e).ToList();
+            if (values.Count == 0)
+            {
+                return 0;
+            }
+
+            return values[values.Count / 2];
         }
 
         /// <inheritdoc />
         public double GetMean()
         {
-            return Data.Select(e => Value(e)).DefaultIfEmpty(double.NaN).Average();
+            return Items.Any() ? Items.Select(Value).Average() : double.NaN;
         }
 
         /// <inheritdoc />
         public double GetMode()
         {
-            return Data.Any() ? Data.GroupBy(e => Value(e)).Select(g => new { Value = g.Key, Count = g.Count() }).OrderByDescending(e => e.Count).FirstOrDefault().Value : double.NaN;
+            if (!Items.Any())
+            {
+                return double.NaN;
+            }
+
+            return Items
+                .GroupBy(item => Value(item))
+                .Select(g => new { Value = g.Key, Count = g.Count() })
+                .OrderByDescending(e => e.Count)
+                .First()
+                .Value;
         }
 
         /// <summary>
@@ -639,33 +693,43 @@ namespace Radzen.Blazor
         {
             double a = double.NaN, b = double.NaN;
 
-            if (Data.Any())
+            var chart = Chart;
+            if (chart == null)
+            {
+                return (a, b);
+            }
+
+            if (Items.Any())
             {
                 Func<TItem, double> X;
                 Func<TItem, double> Y;
-                if (Chart.ShouldInvertAxes())
+                if (chart.ShouldInvertAxes())
                 {
-                    X = e => Chart.CategoryScale.Scale(Value(e));
-                    Y = e => Chart.ValueScale.Scale(Category(Chart.ValueScale)(e));
+                    var valueScale = chart.ValueScale;
+                    var categoryAccessor = Category(chart.ValueScale);
+                    X = e => chart.CategoryScale.Scale(Value(e));
+                    Y = e => valueScale.Scale(categoryAccessor(e));
                 }
                 else
                 {
-                    X = e => Chart.CategoryScale.Scale(Category(Chart.CategoryScale)(e));
-                    Y = e => Chart.ValueScale.Scale(Value(e));
+                    var categoryAccessor = Category(chart.CategoryScale);
+                    X = e => chart.CategoryScale.Scale(categoryAccessor(e));
+                    Y = e => chart.ValueScale.Scale(Value(e));
                 }
 
-                var avgX = Data.Select(e => X(e)).Average();
-                var avgY = Data.Select(e => Y(e)).Average();
-                var sumXY = Data.Sum(e => (X(e) - avgX) * (Y(e) - avgY));
-                if (Chart.ShouldInvertAxes())
+                var data = Items.ToList();
+                var avgX = data.Select(e => X(e)).Average();
+                var avgY = data.Select(e => Y(e)).Average();
+                var sumXY = data.Sum(e => (X(e) - avgX) * (Y(e) - avgY));
+                if (chart.ShouldInvertAxes())
                 {
-                    var sumYSq = Data.Sum(e => (Y(e) - avgY) * (Y(e) - avgY));
+                    var sumYSq = data.Sum(e => (Y(e) - avgY) * (Y(e) - avgY));
                     b = sumXY / sumYSq;
                     a = avgX - b * avgY;
                 }
                 else
                 {
-                    var sumXSq = Data.Sum(e => (X(e) - avgX) * (X(e) - avgX));
+                    var sumXSq = data.Sum(e => (X(e) - avgX) * (X(e) - avgX));
                     b = sumXY / sumXSq;
                     a = avgY - b * avgX;
                 }
@@ -678,7 +742,9 @@ namespace Radzen.Blazor
         {
             IsVisible = !IsVisible;
 
-            if (Chart.LegendClick.HasDelegate)
+            var chart = Chart;
+
+            if (chart?.LegendClick.HasDelegate == true)
             {
                 var args = new LegendClickEventArgs
                 {
@@ -687,18 +753,28 @@ namespace Radzen.Blazor
                     IsVisible = IsVisible,
                 };
 
-                await Chart.LegendClick.InvokeAsync(args);
+                await chart.LegendClick.InvokeAsync(args);
 
                 IsVisible = args.IsVisible;
             }
 
-            await Chart.Refresh();
+            if (chart != null)
+            {
+                await chart.Refresh();
+            }
         }
 
         /// <inheritdoc />
         public string GetTitle()
         {
-            return String.IsNullOrEmpty(Title) ? $"Series {Chart.Series.IndexOf(this) + 1}" : Title;
+            var chart = Chart;
+            if (string.IsNullOrEmpty(Title))
+            {
+                var index = chart?.Series.IndexOf(this) ?? 0;
+                return $"Series {index + 1}";
+            }
+
+            return Title;
         }
 
         /// <summary>
@@ -716,8 +792,9 @@ namespace Radzen.Blazor
         /// <param name="item">The item.</param>
         protected virtual string TooltipTitle(TItem item)
         {
-            var category = Category(Chart.CategoryScale);
-            return Chart.CategoryAxis.Format(Chart.CategoryScale, Chart.CategoryScale.Value(category(item)));
+            var chart = RequireChart();
+            var category = Category(chart.CategoryScale);
+            return chart.CategoryAxis.Format(chart.CategoryScale, chart.CategoryScale.Value(category(item)));
         }
 
         /// <summary>
@@ -727,7 +804,8 @@ namespace Radzen.Blazor
         /// <returns>System.String.</returns>
         protected virtual string TooltipValue(TItem item)
         {
-            return Chart.ValueAxis.Format(Chart.ValueScale, Chart.ValueScale.Value(Value(item)));
+            var chart = RequireChart();
+            return chart.ValueAxis.Format(chart.ValueScale, chart.ValueScale.Value(Value(item)));
         }
 
         /// <summary>
@@ -736,8 +814,9 @@ namespace Radzen.Blazor
         /// <param name="item">The item.</param>
         internal virtual double TooltipX(TItem item)
         {
-            var category = Category(Chart.CategoryScale);
-            return Chart.CategoryScale.Scale(category(item), true);
+            var chart = RequireChart();
+            var category = Category(chart.CategoryScale);
+            return chart.CategoryScale.Scale(category(item), true);
         }
 
         /// <summary>
@@ -746,7 +825,8 @@ namespace Radzen.Blazor
         /// <param name="item">The item.</param>
         internal virtual double TooltipY(TItem item)
         {
-            return Chart.ValueScale.Scale(Value(item), true);
+            var chart = RequireChart();
+            return chart.ValueScale.Scale(Value(item), true);
         }
 
         /// <inheritdoc />
@@ -760,25 +840,26 @@ namespace Radzen.Blazor
                     return new { Item = item, Distance = distance };
                 }).Aggregate((a, b) => a.Distance < b.Distance ? a : b).Item;
 
-                return (retObject,
+                return (retObject!,
                     new Point() { X = TooltipX(retObject), Y = TooltipY(retObject)});
             }
 
-            return (null, null);
+            return (default!, new Point());
         }
 
         /// <inheritdoc />
         public virtual IEnumerable<ChartDataLabel> GetDataLabels(double offsetX, double offsetY)
         {
+            var chart = RequireChart();
             var list = new List<ChartDataLabel>();
 
-            foreach (var d in Data)
+            foreach (var d in Items)
             {
                 list.Add(new ChartDataLabel
                 {
                     Position = new Point { X = TooltipX(d) + offsetX, Y = TooltipY(d) + offsetY },
                     TextAnchor = "middle",
-                    Text = Chart.ValueAxis.Format(Chart.ValueScale, Value(d))
+                    Text = chart.ValueAxis.Format(chart.ValueScale, Value(d))
                 });
             }
 
@@ -793,12 +874,12 @@ namespace Radzen.Blazor
         /// <param name="defaultValue">The default value.</param>
         /// <param name="colorRange">The color range value.</param>
         /// <param name="value">The value of the item.</param>
-        protected string PickColor(int index, IEnumerable<string> colors, string defaultValue = null, IList<SeriesColorRange> colorRange = null, double value = 0.0)
+        protected string? PickColor(int index, IEnumerable<string>? colors, string? defaultValue = null, IList<SeriesColorRange>? colorRange = null, double value = 0.0)
         {
             if (colorRange != null)
             {
                 var result = colorRange.Where(r => r.Min <= value && r.Max >= value).FirstOrDefault<SeriesColorRange>();
-                return result != null ? result.Color : defaultValue;
+                return result?.Color ?? defaultValue;
             }
             else
             {
@@ -819,18 +900,20 @@ namespace Radzen.Blazor
         /// <inheritdoc />
         public async Task InvokeClick(EventCallback<SeriesClickEventArgs> handler, object data)
         {
-            var category = Category(Chart.CategoryScale);
+            var chart = RequireChart();
+            var category = Category(chart.CategoryScale);
+            var dataItem = (TItem)data;
 
             await handler.InvokeAsync(new SeriesClickEventArgs
             {
                 Data = data,
                 Title = GetTitle(),
-                Category = PropertyAccess.GetValue(data, CategoryProperty),
-                Value = PropertyAccess.GetValue(data, ValueProperty),
+                Category = !string.IsNullOrEmpty(CategoryProperty) ? PropertyAccess.GetValue(data, CategoryProperty) : null,
+                Value = !string.IsNullOrEmpty(ValueProperty) ? PropertyAccess.GetValue(data, ValueProperty) : null,
                 Point = new SeriesPoint
                 {
-                    Category = category((TItem)data),
-                    Value = Value((TItem)data)
+                    Category = category(dataItem),
+                    Value = Value(dataItem)
                 }
             });
         }

Radzen.Blazor/ChatMessage.cs

@@ -39,5 +39,5 @@ public class ChatMessage
     /// <summary>
     /// Gets or sets the role associated with the message (e.g., "user", "assistant").
     /// </summary>
-    public string Role { get; set; }
+    public string? Role { get; set; }
 }

Radzen.Blazor/CompositeFilterDescriptor.cs

@@ -12,25 +12,25 @@ public class CompositeFilterDescriptor
     /// Gets or sets the name of the filtered property.
     /// </summary>
     /// <value>The property.</value>
-    public string Property { get; set; }
+    public string? Property { get; set; }
 
     /// <summary>
     /// Gets or sets the property type.
     /// </summary>
     /// <value>The property type.</value>
-    public Type Type { get; set; }
+    public Type? Type { get; set; }
 
     /// <summary>
     /// Gets or sets the name of the filtered property.
     /// </summary>
     /// <value>The property.</value>
-    public string FilterProperty { get; set; }
+    public string? FilterProperty { get; set; }
 
     /// <summary>
     /// Gets or sets the value to filter by.
     /// </summary>
     /// <value>The filter value.</value>
-    public object FilterValue { get; set; }
+    public object? FilterValue { get; set; }
 
     /// <summary>
     /// Gets or sets the operator which will compare the property value with <see cref="FilterValue" />.
@@ -48,6 +48,6 @@ public class CompositeFilterDescriptor
     /// Gets or sets the filters.
     /// </summary>
     /// <value>The filters.</value>
-    public IEnumerable<CompositeFilterDescriptor> Filters { get; set; }
+    public IEnumerable<CompositeFilterDescriptor>? Filters { get; set; }
 }
 

Radzen.Blazor/ContextMenuService.cs

@@ -1,225 +1,227 @@
-using Microsoft.AspNetCore.Components;
-using Microsoft.AspNetCore.Components.Web;
-using System;
-using System.Collections.Generic;
-using System.Linq;
-using System.Threading.Tasks;
-
-namespace Radzen
-{
-    /// <summary>
-    /// Class ContextMenuService. Contains various methods with options to open and close context menus. 
-    /// Should be added as scoped service in the application services and RadzenContextMenu should be added in application main layout.
-    /// Implements the <see cref="IDisposable" />
-    /// </summary>
-    /// <seealso cref="IDisposable" />
-    /// <example>
-    /// <code>
-    /// @inject ContextMenuService ContextMenuService
-    /// &lt;RadzenButton Text="Show context menu" ContextMenu=@(args => ShowContextMenuWithContent(args)) /&gt;
-    /// @code {
-    ///     void ShowContextMenuWithContent(MouseEventArgs args) =&gt; ContextMenuService.Open(args, ds =&gt;
-    ///       @&lt;RadzenMenu Click="OnMenuItemClick"&gt;
-    ///         &lt;RadzenMenuItem Text="Item1" Value="1"&gt;&lt;/RadzenMenuItem&gt;
-    ///         &lt;RadzenMenuItem Text="Item2" Value="2"&gt;&lt;/RadzenMenuItem&gt;
-    ///         &lt;RadzenMenuItem Text="More items" Value="3"&gt;
-    ///             &lt;RadzenMenuItem Text="More sub items" Value="4"&gt;
-    ///                 &lt;RadzenMenuItem Text="Item1" Value="5"&gt;&lt;/RadzenMenuItem&gt;
-    ///                 &lt;RadzenMenuItem Text="Item2" Value="6"&gt;&lt;/RadzenMenuItem&gt;
-    ///             &lt;/RadzenMenuItem&gt;
-    ///         &lt;/RadzenMenuItem&gt;
-    ///       &lt;/RadzenMenu&gt;);
-    /// 
-    ///     void OnMenuItemClick(MenuItemEventArgs args)
-    ///     {
-    ///       Console.WriteLine($"Menu item with Value={args.Value} clicked");
-    ///     }
-    /// }
-    /// </code>
-    /// </example>
-    public class ContextMenuService : IDisposable
-    {
-        /// <summary>
-        /// Gets or sets the navigation manager.
-        /// </summary>
-        /// <value>The navigation manager.</value>
-        NavigationManager navigationManager { get; set; }
-
-        /// <summary>
-        /// Initializes a new instance of the <see cref="ContextMenuService"/> class.
-        /// </summary>
-        /// <param name="uriHelper">The URI helper.</param>
-        public ContextMenuService(NavigationManager uriHelper)
-        {
-            navigationManager = uriHelper;
-
-            if (navigationManager != null)
-            {
-                navigationManager.LocationChanged += UriHelper_OnLocationChanged;
-            }
-        }
-
-        /// <summary>
-        /// Handles the OnLocationChanged event of the UriHelper control.
-        /// </summary>
-        /// <param name="sender">The source of the event.</param>
-        /// <param name="e">The <see cref="Microsoft.AspNetCore.Components.Routing.LocationChangedEventArgs"/> instance containing the event data.</param>
-        private void UriHelper_OnLocationChanged(object sender, Microsoft.AspNetCore.Components.Routing.LocationChangedEventArgs e)
+using Microsoft.AspNetCore.Components;
+using Microsoft.AspNetCore.Components.Web;
+using System;
+using System.Collections.Generic;
+
+namespace Radzen
+{
+    /// <summary>
+    /// Class ContextMenuService. Contains various methods with options to open and close context menus. 
+    /// Should be added as scoped service in the application services and RadzenContextMenu should be added in application main layout.
+    /// Implements the <see cref="IDisposable" />
+    /// </summary>
+    /// <seealso cref="IDisposable" />
+    /// <example>
+    /// <code>
+    /// @inject ContextMenuService ContextMenuService
+    /// &lt;RadzenButton Text="Show context menu" ContextMenu=@(args => ShowContextMenuWithContent(args)) /&gt;
+    /// @code {
+    ///     void ShowContextMenuWithContent(MouseEventArgs args) =&gt; ContextMenuService.Open(args, ds =&gt;
+    ///       @&lt;RadzenMenu Click="OnMenuItemClick"&gt;
+    ///         &lt;RadzenMenuItem Text="Item1" Value="1"&gt;&lt;/RadzenMenuItem&gt;
+    ///         &lt;RadzenMenuItem Text="Item2" Value="2"&gt;&lt;/RadzenMenuItem&gt;
+    ///         &lt;RadzenMenuItem Text="More items" Value="3"&gt;
+    ///             &lt;RadzenMenuItem Text="More sub items" Value="4"&gt;
+    ///                 &lt;RadzenMenuItem Text="Item1" Value="5"&gt;&lt;/RadzenMenuItem&gt;
+    ///                 &lt;RadzenMenuItem Text="Item2" Value="6"&gt;&lt;/RadzenMenuItem&gt;
+    ///             &lt;/RadzenMenuItem&gt;
+    ///         &lt;/RadzenMenuItem&gt;
+    ///       &lt;/RadzenMenu&gt;);
+    /// 
+    ///     void OnMenuItemClick(MenuItemEventArgs args)
+    ///     {
+    ///       Console.WriteLine($"Menu item with Value={args.Value} clicked");
+    ///     }
+    /// }
+    /// </code>
+    /// </example>
+    public class ContextMenuService : IDisposable
+    {
+        /// <summary>
+        /// Gets or sets the navigation manager.
+        /// </summary>
+        /// <value>The navigation manager.</value>
+        NavigationManager? navigationManager { get; set; }
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="ContextMenuService"/> class.
+        /// </summary>
+        /// <param name="uriHelper">The URI helper.</param>
+        public ContextMenuService(NavigationManager? uriHelper)
         {
-            this.OnNavigate?.Invoke();
-        }
-
-        /// <summary>
-        /// Occurs when [on navigate].
-        /// </summary>
-        public event Action OnNavigate;
-
-        /// <summary>
-        /// Raises the Close event.
-        /// </summary>
-        public event Action OnClose;
-
-        /// <summary>
-        /// Occurs when [on open].
-        /// </summary>
-        public event Action<MouseEventArgs, ContextMenuOptions> OnOpen;
-
-        /// <summary>
-        /// Opens the specified arguments.
-        /// </summary>
-        /// <param name="args">The <see cref="MouseEventArgs"/> instance containing the event data.</param>
-        /// <param name="items">The items.</param>
-        /// <param name="click">The click.</param>
-        public void Open(MouseEventArgs args, IEnumerable<ContextMenuItem> items, Action<MenuItemEventArgs> click = null)
-        {
-            var options = new ContextMenuOptions();
-
-            options.Items = items;
-            options.Click = click;
-
-            OpenTooltip(args, options);
-        }
-
-        /// <summary>
-        /// Opens the specified arguments.
-        /// </summary>
-        /// <param name="args">The <see cref="MouseEventArgs"/> instance containing the event data.</param>
-        /// <param name="childContent">Content of the child.</param>
-        public void Open(MouseEventArgs args, RenderFragment<ContextMenuService> childContent)
-        {
-            var options = new ContextMenuOptions();
-
-            options.ChildContent = childContent;
-
-            OpenTooltip(args, options);
-        }
-
-        /// <summary>
-        /// Opens the tooltip.
-        /// </summary>
-        /// <param name="args">The <see cref="MouseEventArgs"/> instance containing the event data.</param>
-        /// <param name="options">The options.</param>
-        private void OpenTooltip(MouseEventArgs args, ContextMenuOptions options)
-        {
-            OnOpen?.Invoke(args, options);
-        }
-
-        /// <summary>
-        /// Closes this instance.
-        /// </summary>
-        public void Close()
-        {
-            OnClose?.Invoke();
-        }
-
-        /// <summary>
-        /// Disposes this instance.
-        /// </summary>
-        public void Dispose()
-        {
-            navigationManager.LocationChanged -= UriHelper_OnLocationChanged;
-        }
-    }
-
-    /// <summary>
-    /// Class ContextMenuOptions.
-    /// </summary>
-    public class ContextMenuOptions
-    {
-        /// <summary>
-        /// Gets or sets the child content.
-        /// </summary>
-        /// <value>The child content.</value>
-        public RenderFragment<ContextMenuService> ChildContent { get; set; }
-        /// <summary>
-        /// Gets or sets the items.
-        /// </summary>
-        /// <value>The items.</value>
-        public IEnumerable<ContextMenuItem> Items { get; set; }
-
-        /// <summary>
-        /// Gets or sets the click.
-        /// </summary>
-        /// <value>The click.</value>
-        public Action<MenuItemEventArgs> Click { get; set; }
-    }
-
-    /// <summary>
-    /// Class ContextMenu.
-    /// </summary>
-    public class ContextMenu
-    {
-        /// <summary>
-        /// Gets or sets the options.
-        /// </summary>
-        /// <value>The options.</value>
-        public ContextMenuOptions Options { get; set; }
-        /// <summary>
-        /// Gets or sets the mouse event arguments.
-        /// </summary>
-        /// <value>The mouse event arguments.</value>
-        public MouseEventArgs MouseEventArgs { get; set; }
-    }
-
-    /// <summary>
-    /// Class ContextMenuItem.
-    /// </summary>
-    public class ContextMenuItem
-    {
-        /// <summary>
-        /// Gets or sets the text.
-        /// </summary>
-        /// <value>The text.</value>
-        public string Text { get; set; }
-        /// <summary>
-        /// Gets or sets the value.
-        /// </summary>
-        /// <value>The value.</value>
-        public object Value { get; set; }
-        /// <summary>
-        /// Gets or sets the icon.
-        /// </summary>
-        /// <value>The icon.</value>
-        public string Icon { get; set; }
-        /// <summary>
-        /// Gets or sets the icon color.
-        /// </summary>
-        /// <value>The icon color.</value>
-        public string IconColor { get; set; }
-        /// <summary>
-        /// Gets or sets the image.
-        /// </summary>
-        /// <value>The image.</value>
-        public string Image { get; set; }
-        /// <summary>
-        /// Gets or sets the image style.
-        /// </summary>
-        /// <value>The image style.</value>
-        public string ImageStyle { get; set; }
-        /// <summary>
-        /// Gets a value indicating whether this instance is disabled.
-        /// </summary>
-        /// <value><c>true</c> if this instance is disabled; otherwise, <c>false</c>.</value>
-        public bool Disabled { get; set; }
-    }
-}
+            navigationManager = uriHelper;
+
+            if (navigationManager != null)
+            {
+                navigationManager.LocationChanged += UriHelper_OnLocationChanged;
+            }
+        }
+
+        /// <summary>
+        /// Handles the OnLocationChanged event of the UriHelper control.
+        /// </summary>
+        /// <param name="sender">The source of the event.</param>
+        /// <param name="e">The <see cref="Microsoft.AspNetCore.Components.Routing.LocationChangedEventArgs"/> instance containing the event data.</param>
+        private void UriHelper_OnLocationChanged(object? sender, Microsoft.AspNetCore.Components.Routing.LocationChangedEventArgs e)
+        {
+            this.OnNavigate?.Invoke();
+        }
+
+        /// <summary>
+        /// Occurs when [on navigate].
+        /// </summary>
+        public event Action? OnNavigate;
+
+        /// <summary>
+        /// Raises the Close event.
+        /// </summary>
+        public event Action? OnClose;
+
+        /// <summary>
+        /// Occurs when [on open].
+        /// </summary>
+        public event Action<MouseEventArgs, ContextMenuOptions>? OnOpen;
+
+        /// <summary>
+        /// Opens the specified arguments.
+        /// </summary>
+        /// <param name="args">The <see cref="MouseEventArgs"/> instance containing the event data.</param>
+        /// <param name="items">The items.</param>
+        /// <param name="click">The click.</param>
+        public void Open(MouseEventArgs args, IEnumerable<ContextMenuItem> items, Action<MenuItemEventArgs>? click = null)
+        {
+            var options = new ContextMenuOptions();
+
+            options.Items = items;
+            options.Click = click;
+
+            OpenTooltip(args, options);
+        }
+
+        /// <summary>
+        /// Opens the specified arguments.
+        /// </summary>
+        /// <param name="args">The <see cref="MouseEventArgs"/> instance containing the event data.</param>
+        /// <param name="childContent">Content of the child.</param>
+        public void Open(MouseEventArgs args, RenderFragment<ContextMenuService> childContent)
+        {
+            var options = new ContextMenuOptions();
+
+            options.ChildContent = childContent;
+
+            OpenTooltip(args, options);
+        }
+
+        /// <summary>
+        /// Opens the tooltip.
+        /// </summary>
+        /// <param name="args">The <see cref="MouseEventArgs"/> instance containing the event data.</param>
+        /// <param name="options">The options.</param>
+        private void OpenTooltip(MouseEventArgs args, ContextMenuOptions options)
+        {
+            OnOpen?.Invoke(args, options);
+        }
+
+        /// <summary>
+        /// Closes this instance.
+        /// </summary>
+        public void Close()
+        {
+            OnClose?.Invoke();
+        }
+
+        /// <summary>
+        /// Disposes this instance.
+        /// </summary>
+        public void Dispose()
+        {
+            if (navigationManager != null)
+            {
+                navigationManager.LocationChanged -= UriHelper_OnLocationChanged;
+            }
+            GC.SuppressFinalize(this);
+        }
+    }
+
+    /// <summary>
+    /// Class ContextMenuOptions.
+    /// </summary>
+    public class ContextMenuOptions
+    {
+        /// <summary>
+        /// Gets or sets the child content.
+        /// </summary>
+        /// <value>The child content.</value>
+        public RenderFragment<ContextMenuService>? ChildContent { get; set; }
+        /// <summary>
+        /// Gets or sets the items.
+        /// </summary>
+        /// <value>The items.</value>
+        public IEnumerable<ContextMenuItem>? Items { get; set; }
+
+        /// <summary>
+        /// Gets or sets the click.
+        /// </summary>
+        /// <value>The click.</value>
+        public Action<MenuItemEventArgs>? Click { get; set; }
+    }
+
+    /// <summary>
+    /// Class ContextMenu.
+    /// </summary>
+    public class ContextMenu
+    {
+        /// <summary>
+        /// Gets or sets the options.
+        /// </summary>
+        /// <value>The options.</value>
+        public ContextMenuOptions? Options { get; set; }
+        /// <summary>
+        /// Gets or sets the mouse event arguments.
+        /// </summary>
+        /// <value>The mouse event arguments.</value>
+        public MouseEventArgs? MouseEventArgs { get; set; }
+    }
+
+    /// <summary>
+    /// Class ContextMenuItem.
+    /// </summary>
+    public class ContextMenuItem
+    {
+        /// <summary>
+        /// Gets or sets the text.
+        /// </summary>
+        /// <value>The text.</value>
+        public string? Text { get; set; }
+        /// <summary>
+        /// Gets or sets the value.
+        /// </summary>
+        /// <value>The value.</value>
+        public object? Value { get; set; }
+        /// <summary>
+        /// Gets or sets the icon.
+        /// </summary>
+        /// <value>The icon.</value>
+        public string? Icon { get; set; }
+        /// <summary>
+        /// Gets or sets the icon color.
+        /// </summary>
+        /// <value>The icon color.</value>
+        public string? IconColor { get; set; }
+        /// <summary>
+        /// Gets or sets the image.
+        /// </summary>
+        /// <value>The image.</value>
+        public string? Image { get; set; }
+        /// <summary>
+        /// Gets or sets the image style.
+        /// </summary>
+        /// <value>The image style.</value>
+        public string? ImageStyle { get; set; }
+        /// <summary>
+        /// Gets a value indicating whether this instance is disabled.
+        /// </summary>
+        /// <value><c>true</c> if this instance is disabled; otherwise, <c>false</c>.</value>
+        public bool Disabled { get; set; }
+    }
+}

Radzen.Blazor/ConvertType.cs

@@ -18,25 +18,39 @@ public static class ConvertType
     /// <param name="type">The type.</param>
     /// <param name="culture">The culture.</param>
     /// <returns>System.Object</returns>
-    public static object ChangeType(object value, Type type, CultureInfo culture = null)
+    public static object? ChangeType(object value, Type type, CultureInfo? culture = null)
     {
+        ArgumentNullException.ThrowIfNull(type);
+
+        // CA1062: Validate 'value' is non-null before using it
+        if (value == null)
+        {
+            if (Nullable.GetUnderlyingType(type) != null)
+            {
+                return null;
+            }
+            throw new ArgumentNullException(nameof(value));
+        }
+
         if (culture == null)
         {
             culture = CultureInfo.CurrentCulture;
         }
-        if (value == null && Nullable.GetUnderlyingType(type) != null)
-        {
-            return value;
-        }
 
         if ((Nullable.GetUnderlyingType(type) ?? type) == typeof(Guid) && value is string)
         {
             return Guid.Parse((string)value);
         }
 
-        if (Nullable.GetUnderlyingType(type)?.IsEnum == true)
+        var underlyingEnumType = Nullable.GetUnderlyingType(type);
+        if (underlyingEnumType?.IsEnum == true)
         {
-            return Enum.Parse(Nullable.GetUnderlyingType(type), value.ToString());
+            var valueString = value.ToString();
+            if (valueString == null)
+            {
+                throw new ArgumentNullException(nameof(value), "Enum value cannot be null.");
+            }
+            return Enum.Parse(underlyingEnumType, valueString);
         }
 
         if (type.IsGenericType && type.GetGenericTypeDefinition() == typeof(IEnumerable<>))

Radzen.Blazor/CookieThemeService.cs

@@ -44,12 +44,12 @@ namespace Radzen
         /// <summary>
         /// Gets or sets a value indicating whether to use secure cookies.
         /// </summary>
-        public bool IsSecure { get; set; } = false;
+        public bool IsSecure { get; set; }
 
         /// <summary>
         /// Gets or sets the SameSite attribute for the cookie.
         /// </summary>
-        public CookieSameSiteMode? SameSite { get; set; } = null;
+        public CookieSameSiteMode? SameSite { get; set; }
     }
 
     /// <summary>
@@ -64,13 +64,16 @@ namespace Radzen
         /// <summary>
         /// Initializes a new instance of the <see cref="CookieThemeService" /> class.
         /// </summary>
-        public CookieThemeService(IJSRuntime jsRuntime, ThemeService themeService, IOptions<CookieThemeServiceOptions> options)
+        public CookieThemeService(IJSRuntime jsRuntime, ThemeService themeService, IOptions<CookieThemeServiceOptions>? options)
         {
             this.jsRuntime = jsRuntime;
             this.themeService = themeService;
-            this.options = options.Value;
+            this.options = options?.Value ?? new CookieThemeServiceOptions();
 
-            themeService.ThemeChanged += OnThemeChanged;
+            if (themeService != null)
+            {
+                themeService.ThemeChanged += OnThemeChanged;
+            }
 
             _ = InitializeAsync();
         }

Radzen.Blazor/DataBoundFormComponent.cs

@@ -47,14 +47,14 @@ namespace Radzen
         /// </summary>
         /// <value>The name.</value>
         [Parameter]
-        public string Name { get; set; }
+        public string? Name { get; set; }
 
         /// <summary>
         /// Gets or sets the placeholder.
         /// </summary>
         /// <value>The placeholder.</value>
         [Parameter]
-        public string Placeholder { get; set; }
+        public string? Placeholder { get; set; }
 
         /// <summary>
         /// Gets or sets a value indicating whether this <see cref="DataBoundFormComponent{T}"/> is disabled.
@@ -80,36 +80,36 @@ namespace Radzen
         /// <summary>
         /// The form
         /// </summary>
-        IRadzenForm _form;
+        IRadzenForm? form;
 
         /// <summary>
         /// Gets or sets the form.
         /// </summary>
         /// <value>The form.</value>
         [CascadingParameter]
-        public IRadzenForm Form
+        public IRadzenForm? Form
         {
             get
             {
-                return _form;
+                return form;
             }
             set
             {
-                _form = value;
-                _form?.AddComponent(this);
+                form = value;
+                form?.AddComponent(this);
             }
         }
 
         /// <summary>
         /// The value
         /// </summary>
-        private T _value = default;
+        private T? _value;
         /// <summary>
         /// Gets or sets the value.
         /// </summary>
         /// <value>The value.</value>
         [Parameter]
-        public T Value
+        public T? Value
         {
             get
             {
@@ -167,18 +167,18 @@ namespace Radzen
         /// </summary>
         /// <value>The text property.</value>
         [Parameter]
-        public string TextProperty { get; set; }
+        public string? TextProperty { get; set; }
 
         /// <summary>
         /// The data
         /// </summary>
-        IEnumerable _data = null;
+        IEnumerable? _data;
         /// <summary>
         /// Gets or sets the data.
         /// </summary>
         /// <value>The data.</value>
         [Parameter]
-        public virtual IEnumerable Data
+        public virtual IEnumerable? Data
         {
             get
             {
@@ -208,7 +208,7 @@ namespace Radzen
         /// Gets the query.
         /// </summary>
         /// <value>The query.</value>
-        protected virtual IQueryable Query
+        protected virtual IQueryable? Query
         {
             get
             {
@@ -220,7 +220,7 @@ namespace Radzen
         /// Gets or sets the search text
         /// </summary>
         [Parameter]
-        public string SearchText
+        public string? SearchText
         {
             get
             {
@@ -245,29 +245,30 @@ namespace Radzen
         /// <summary>
         /// The search text
         /// </summary>
-        internal string searchText;
+        internal string? searchText;
 
         /// <summary>
         /// The view
         /// </summary>
-        protected IQueryable _view = null;
+        protected IQueryable? _view;
         /// <summary>
         /// Gets the view.
         /// </summary>
         /// <value>The view.</value>
-        protected virtual IEnumerable View
+        protected virtual IEnumerable? View
         {
             get
             {
-                if (_view == null && Query != null)
+                var query = Query;
+                if (_view == null && query != null)
                 {
-                    if (!string.IsNullOrEmpty(searchText))
+                    if (!string.IsNullOrEmpty(searchText) && !string.IsNullOrEmpty(TextProperty))
                     {
-                        _view = Query.Where(TextProperty, searchText, FilterOperator, FilterCaseSensitivity);
+                        _view = query.Where(TextProperty, searchText, FilterOperator, FilterCaseSensitivity);
                     }
                     else
                     {
-                        _view = (typeof(IQueryable).IsAssignableFrom(Data.GetType())) ? Query.Cast<object>().ToList().AsQueryable() : Query;
+                        _view = Data is IQueryable ? query.Cast<object>().ToList().AsQueryable() : query;
                     }
                 }
 
@@ -275,14 +276,14 @@ namespace Radzen
             }
         }
 
-        internal IEnumerable GetView() => View;
+        internal IEnumerable? GetView() => View;
 
         /// <summary>
         /// Gets or sets the edit context.
         /// </summary>
         /// <value>The edit context.</value>
         [CascadingParameter]
-        public EditContext EditContext { get; set; }
+        public EditContext? EditContext { get; set; }
 
         /// <summary>
         /// Gets the field identifier.
@@ -296,7 +297,7 @@ namespace Radzen
         /// </summary>
         /// <value>The value expression.</value>
         [Parameter]
-        public Expression<Func<T>> ValueExpression { get; set; }
+        public Expression<Func<T>>? ValueExpression { get; set; }
         /// <summary>
         /// Set parameters as an asynchronous operation.
         /// </summary>
@@ -338,7 +339,7 @@ namespace Radzen
         /// </summary>
         /// <param name="sender">The sender.</param>
         /// <param name="e">The <see cref="ValidationStateChangedEventArgs"/> instance containing the event data.</param>
-        private void ValidationStateChanged(object sender, ValidationStateChangedEventArgs e)
+        private void ValidationStateChanged(object? sender, ValidationStateChangedEventArgs e)
         {
             StateHasChanged();
         }
@@ -356,13 +357,15 @@ namespace Radzen
             }
 
             Form?.RemoveComponent(this);
+
+            GC.SuppressFinalize(this);
         }
 
         /// <summary>
         /// Gets the value.
         /// </summary>
         /// <returns>System.Object.</returns>
-        public virtual object GetValue()
+        public virtual object? GetValue()
         {
             return Value;
         }
@@ -386,13 +389,13 @@ namespace Radzen
 
         /// <summary> Provides support for RadzenFormField integration. </summary>
         [CascadingParameter]
-        public IFormFieldContext FormFieldContext { get; set; }
+        public IFormFieldContext? FormFieldContext { get; set; }
 
         /// <summary> Gets the current placeholder. Returns empty string if this component is inside a RadzenFormField.</summary>
-        protected string CurrentPlaceholder => FormFieldContext?.AllowFloatingLabel == true ? " " : Placeholder;
+        protected string? CurrentPlaceholder => FormFieldContext?.AllowFloatingLabel == true ? " " : Placeholder;
 
         /// <summary>
-        /// Handles the <see cref="E:ContextMenu" /> event.
+        /// Handles the ContextMenu event.
         /// </summary>
         /// <param name="args">The <see cref="MouseEventArgs"/> instance containing the event data.</param>
         /// <returns>Task.</returns>

Radzen.Blazor/DataGridCellMouseEventArgs.cs

@@ -6,16 +6,16 @@ namespace Radzen;
 /// Supplies information about a <see cref="RadzenDataGrid{TItem}.CellContextMenu" /> event that is being raised.
 /// </summary>
 /// <typeparam name="T">The data item type.</typeparam>
-public class DataGridCellMouseEventArgs<T> : Microsoft.AspNetCore.Components.Web.MouseEventArgs
+public class DataGridCellMouseEventArgs<T> : Microsoft.AspNetCore.Components.Web.MouseEventArgs where T : notnull
 {
     /// <summary>
     /// Gets the data item which the clicked DataGrid row represents.
     /// </summary>
-    public T Data { get; internal set; }
+    public T? Data { get; internal set; }
 
     /// <summary>
     /// Gets the RadzenDataGridColumn which this cells represents.
     /// </summary>
-    public RadzenDataGridColumn<T> Column { get; internal set; }
+    public RadzenDataGridColumn<T>? Column { get; internal set; }
 }
 

Radzen.Blazor/DataGridCellRenderEventArgs.cs

@@ -6,11 +6,11 @@ namespace Radzen;
 /// Supplies information about a <see cref="RadzenDataGrid{TItem}.CellRender" /> event that is being raised.
 /// </summary>
 /// <typeparam name="T">The data item type.</typeparam>
-public class DataGridCellRenderEventArgs<T> : RowRenderEventArgs<T>
+public class DataGridCellRenderEventArgs<T> : RowRenderEventArgs<T> where T : notnull
 {
     /// <summary>
     /// Gets the RadzenDataGridColumn which this cells represents.
     /// </summary>
-    public RadzenDataGridColumn<T> Column { get; internal set; }
+    public RadzenDataGridColumn<T>? Column { get; internal set; }
 }
 

Radzen.Blazor/DataGridChildData.cs

@@ -11,7 +11,7 @@ internal class DataGridChildData<T>
     /// <summary>
     /// Gets or sets the parent child data.
     /// </summary>
-    internal DataGridChildData<T> ParentChildData { get; set; }
+    internal DataGridChildData<T>? ParentChildData { get; set; }
 
     /// <summary>
     /// Gets or sets the level.
@@ -21,6 +21,6 @@ internal class DataGridChildData<T>
     /// <summary>
     /// Gets or sets the data.
     /// </summary>
-    internal IEnumerable<T> Data { get; set; }
+    internal IEnumerable<T>? Data { get; set; }
 }
 

Radzen.Blazor/DataGridColumnFilterEventArgs.cs

@@ -6,22 +6,22 @@ namespace Radzen;
 /// Supplies information about a <see cref="RadzenDataGrid{TItem}.Filter" /> event that is being raised.
 /// </summary>
 /// <typeparam name="T">The data item type.</typeparam>
-public class DataGridColumnFilterEventArgs<T>
+public class DataGridColumnFilterEventArgs<T> where T : notnull
 {
     /// <summary>
     /// Gets the filtered RadzenDataGridColumn.
     /// </summary>
-    public RadzenDataGridColumn<T> Column { get; internal set; }
+    public RadzenDataGridColumn<T>? Column { get; internal set; }
 
     /// <summary>
     /// Gets the new filter value of the filtered column.
     /// </summary>
-    public object FilterValue { get; internal set; }
+    public object? FilterValue { get; internal set; }
 
     /// <summary>
     /// Gets the new second filter value of the filtered column.
     /// </summary>
-    public object SecondFilterValue { get; internal set; }
+    public object? SecondFilterValue { get; internal set; }
 
     /// <summary>
     /// Gets the new filter operator of the filtered column.

Radzen.Blazor/DataGridColumnGroupEventArgs.cs

@@ -6,16 +6,16 @@ namespace Radzen;
 /// Supplies information about a <see cref="RadzenDataGrid{TItem}.Group" /> event that is being raised.
 /// </summary>
 /// <typeparam name="T">The data item type.</typeparam>
-public class DataGridColumnGroupEventArgs<T>
+public class DataGridColumnGroupEventArgs<T> where T : notnull
 {
     /// <summary>
     /// Gets the grouped RadzenDataGridColumn.
     /// </summary>
-    public RadzenDataGridColumn<T> Column { get; internal set; }
+    public RadzenDataGridColumn<T>? Column { get; internal set; }
 
     /// <summary>
     /// Gets the group descriptor.
     /// </summary>
-    public GroupDescriptor GroupDescriptor { get; internal set; }
+    public GroupDescriptor? GroupDescriptor { get; internal set; }
 }
 

Radzen.Blazor/DataGridColumnReorderedEventArgs.cs

@@ -6,12 +6,12 @@ namespace Radzen;
 /// Supplies information about a <see cref="RadzenDataGrid{TItem}.ColumnReordered" /> event that is being raised.
 /// </summary>
 /// <typeparam name="T">The data item type.</typeparam>
-public class DataGridColumnReorderedEventArgs<T>
+public class DataGridColumnReorderedEventArgs<T> where T : notnull
 {
     /// <summary>
     /// Gets the reordered RadzenDataGridColumn.
     /// </summary>
-    public RadzenDataGridColumn<T> Column { get; internal set; }
+    public RadzenDataGridColumn<T>? Column { get; internal set; }
 
     /// <summary>
     /// Gets the old index of the column.

Radzen.Blazor/DataGridColumnReorderingEventArgs.cs

@@ -6,17 +6,17 @@ namespace Radzen;
 /// Supplies information about a <see cref="RadzenDataGrid{TItem}.ColumnReordering" /> event that is being raised.
 /// </summary>
 /// <typeparam name="T">The data item type.</typeparam>
-public class DataGridColumnReorderingEventArgs<T>
+public class DataGridColumnReorderingEventArgs<T> where T : notnull
 {
     /// <summary>
     /// Gets the reordered RadzenDataGridColumn.
     /// </summary>
-    public RadzenDataGridColumn<T> Column { get; internal set; }
+    public RadzenDataGridColumn<T>? Column { get; internal set; }
 
     /// <summary>
     /// Gets the reordered to RadzenDataGridColumn.
     /// </summary>
-    public RadzenDataGridColumn<T> ToColumn { get; internal set; }
+    public RadzenDataGridColumn<T>? ToColumn { get; internal set; }
 
     /// <summary>
     /// Gets or sets a value which will cancel the event.

Radzen.Blazor/DataGridColumnResizedEventArgs.cs

@@ -6,12 +6,12 @@ namespace Radzen;
 /// Supplies information about a <see cref="RadzenDataGrid{TItem}.ColumnResized" /> event that is being raised.
 /// </summary>
 /// <typeparam name="T">The data item type.</typeparam>
-public class DataGridColumnResizedEventArgs<T>
+public class DataGridColumnResizedEventArgs<T> where T : notnull
 {
     /// <summary>
     /// Gets the resized RadzenDataGridColumn.
     /// </summary>
-    public RadzenDataGridColumn<T> Column { get; internal set; }
+    public RadzenDataGridColumn<T>? Column { get; internal set; }
 
     /// <summary>
     /// Gets the new width of the resized column.

Radzen.Blazor/DataGridColumnSettings.cs

@@ -8,12 +8,12 @@ public class DataGridColumnSettings
     /// <summary>
     /// Property.
     /// </summary>
-    public string UniqueID { get; set; }
+    public string UniqueID { get; set; } = string.Empty;
 
     /// <summary>
     /// Property.
     /// </summary>
-    public string Property { get; set; }
+    public string Property { get; set; } = string.Empty;
 
     /// <summary>
     /// Visible.
@@ -23,7 +23,7 @@ public class DataGridColumnSettings
     /// <summary>
     /// Width.
     /// </summary>
-    public string Width { get; set; }
+    public string Width { get; set; } = string.Empty;
 
     /// <summary>
     /// OrderIndex.
@@ -43,7 +43,7 @@ public class DataGridColumnSettings
     /// <summary>
     /// FilterValue.
     /// </summary>
-    public object FilterValue { get; set; }
+    public object? FilterValue { get; set; }
 
     /// <summary>
     /// FilterOperator.
@@ -53,7 +53,7 @@ public class DataGridColumnSettings
     /// <summary>
     /// SecondFilterValue.
     /// </summary>
-    public object SecondFilterValue { get; set; }
+    public object? SecondFilterValue { get; set; }
 
     /// <summary>
     /// SecondFilterOperator.
@@ -68,7 +68,7 @@ public class DataGridColumnSettings
     /// <summary>
     /// CustomFilterExpression.
     /// </summary>
-    public string CustomFilterExpression { get; set; }
+    public string CustomFilterExpression { get; set; } = string.Empty;
 
     /// <summary>
     /// Gets or sets the mode that determines whether the filter applies to any or all items in a collection.

Radzen.Blazor/DataGridColumnSortEventArgs.cs

@@ -6,12 +6,12 @@ namespace Radzen;
 /// Supplies information about a <see cref="RadzenDataGrid{TItem}.Sort" /> event that is being raised.
 /// </summary>
 /// <typeparam name="T">The data item type.</typeparam>
-public class DataGridColumnSortEventArgs<T>
+public class DataGridColumnSortEventArgs<T> where T : notnull
 {
     /// <summary>
     /// Gets the sorted RadzenDataGridColumn.
     /// </summary>
-    public RadzenDataGridColumn<T> Column { get; internal set; }
+    public RadzenDataGridColumn<T>? Column { get; internal set; }
 
     /// <summary>
     /// Gets the new sort order of the sorted column.

Radzen.Blazor/DataGridLoadChildDataEventArgs.cs

@@ -12,12 +12,12 @@ public class DataGridLoadChildDataEventArgs<T>
     /// Gets or sets the data.
     /// </summary>
     /// <value>The data.</value>
-    public IEnumerable<T> Data { get; set; }
+    public IEnumerable<T>? Data { get; set; }
 
     /// <summary>
     /// Gets the item.
     /// </summary>
     /// <value>The item.</value>
-    public T Item { get; internal set; }
+    public T? Item { get; internal set; }
 }
 

Radzen.Blazor/DataGridLoadColumnFilterDataEventArgs.cs

@@ -8,13 +8,13 @@ namespace Radzen;
 /// Supplies information about a <see cref="Radzen.Blazor.RadzenDataGrid{TItem}.LoadColumnFilterData" /> event that is being raised.
 /// </summary>
 /// <typeparam name="T">The data item type.</typeparam>
-public class DataGridLoadColumnFilterDataEventArgs<T>
+public class DataGridLoadColumnFilterDataEventArgs<T> where T : notnull
 {
     /// <summary>
     /// Gets or sets the data.
     /// </summary>
     /// <value>The data.</value>
-    public IEnumerable Data { get; set; }
+    public IEnumerable? Data { get; set; }
 
     /// <summary>
     /// Gets or sets the total data count.
@@ -37,17 +37,17 @@ public class DataGridLoadColumnFilterDataEventArgs<T>
     /// Gets the filter expression as a string.
     /// </summary>
     /// <value>The filter.</value>
-    public string Filter { get; internal set; }
+    public string? Filter { get; internal set; }
 
     /// <summary>
     /// Gets or sets filter property used to limit and distinct values, if not set, args.Data are used as values.
     /// </summary>
     /// <value>The filter property.</value>
-    public string Property { get; set; }
+    public string? Property { get; set; }
 
     /// <summary>
     /// Gets the RadzenDataGridColumn.
     /// </summary>
-    public Radzen.Blazor.RadzenDataGridColumn<T> Column { get; internal set; }
+    public Radzen.Blazor.RadzenDataGridColumn<T>? Column { get; internal set; }
 }
 

Radzen.Blazor/DataGridLoadSettingsEventArgs.cs

@@ -8,6 +8,6 @@ public class DataGridLoadSettingsEventArgs
     /// <summary>
     /// Gets or sets the settings.
     /// </summary>
-    public DataGridSettings Settings { get; set; }
+    public DataGridSettings? Settings { get; set; }
 }
 

Radzen.Blazor/DataGridPickedColumnsChangedEventArgs.cs

@@ -7,11 +7,11 @@ namespace Radzen;
 /// Supplies information about a <see cref="RadzenDataGrid{TItem}.PickedColumnsChanged" /> event that is being raised.
 /// </summary>
 /// <typeparam name="T">The data item type.</typeparam>
-public class DataGridPickedColumnsChangedEventArgs<T>
+public class DataGridPickedColumnsChangedEventArgs<T> where T : notnull
 {
     /// <summary>
     /// Gets the picked columns.
     /// </summary>
-    public IEnumerable<RadzenDataGridColumn<T>> Columns { get; internal set; }
+    public IEnumerable<RadzenDataGridColumn<T>>? Columns { get; internal set; }
 }
 

Radzen.Blazor/DataGridRenderEventArgs.cs

@@ -6,12 +6,12 @@ namespace Radzen;
 /// Supplies information about a <see cref="RadzenDataGrid{TItem}.Render" /> event that is being raised.
 /// </summary>
 /// <typeparam name="T">The data item type.</typeparam>
-public class DataGridRenderEventArgs<T>
+public class DataGridRenderEventArgs<T> where T : notnull
 {
     /// <summary>
     /// Gets the instance of the RadzenDataGrid component which has rendered.
     /// </summary>
-    public RadzenDataGrid<T> Grid { get; internal set; }
+    public RadzenDataGrid<T>? Grid { get; internal set; }
 
     /// <summary>
     /// Gets a value indicating whether this is the first time the RadzenDataGrid has rendered.

Radzen.Blazor/DataGridRowMouseEventArgs.cs

@@ -9,6 +9,6 @@ public class DataGridRowMouseEventArgs<T> : Microsoft.AspNetCore.Components.Web.
     /// <summary>
     /// Gets the data item which the clicked DataGrid row represents.
     /// </summary>
-    public T Data { get; internal set; }
+    public T? Data { get; internal set; }
 }
 

Radzen.Blazor/DataGridSettings.cs

@@ -10,12 +10,12 @@ public class DataGridSettings
     /// <summary>
     /// Columns.
     /// </summary>
-    public IEnumerable<DataGridColumnSettings> Columns { get; set; }
+    public IEnumerable<DataGridColumnSettings> Columns { get; set; } = System.Array.Empty<DataGridColumnSettings>();
 
     /// <summary>
     /// Groups.
     /// </summary>
-    public IEnumerable<GroupDescriptor> Groups { get; set; }
+    public IEnumerable<GroupDescriptor> Groups { get; set; } = System.Array.Empty<GroupDescriptor>();
 
     /// <summary>
     /// CurrentPage.

Radzen.Blazor/DateScale.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Globalization;
 using System.Linq;
 using System.Collections.Generic;
 
@@ -50,14 +51,14 @@ namespace Radzen.Blazor
         {
             if (min != null)
             {
-                var minDate = Convert.ToDateTime(min);
+                var minDate = Convert.ToDateTime(min, CultureInfo.InvariantCulture);
                 Input.Start = minDate.Ticks;
                 Round = false;
             }
 
             if (max != null)
             {
-                var maxDate = Convert.ToDateTime(max);
+                var maxDate = Convert.ToDateTime(max, CultureInfo.InvariantCulture);
                 Input.End = maxDate.Ticks;
                 Round = false;
             }

Radzen.Blazor/Debouncer.cs

@@ -6,9 +6,9 @@ namespace Radzen;
 /// <summary>
 /// Utility class for debouncing and throttling function calls.
 /// </summary>
-internal class Debouncer
+internal class Debouncer : IDisposable
 {
-    private System.Timers.Timer timer;
+    private System.Timers.Timer? timer;
     private DateTime timerStarted { get; set; } = DateTime.UtcNow.AddYears(-1);
 
     /// <summary>
@@ -86,4 +86,15 @@ internal class Debouncer
         timer.Start();
         timerStarted = curTime;
     }
+
+    /// <inheritdoc />
+    public void Dispose()
+    {
+        if(timer != null)
+        {
+            timer.Stop();
+            timer.Dispose();
+            timer = null;
+        }
+    }
 }

Radzen.Blazor/DialogService.cs

@@ -41,8 +41,8 @@ namespace Radzen
     /// </example>
     public class DialogService : IDisposable
     {
-        private DotNetObjectReference<DialogService> reference;
-        internal DotNetObjectReference<DialogService> Reference
+        private DotNetObjectReference<DialogService>? reference;
+        internal DotNetObjectReference<DialogService>? Reference
         {
             get
             {
@@ -59,15 +59,15 @@ namespace Radzen
         /// Gets or sets the URI helper.
         /// </summary>
         /// <value>The URI helper.</value>
-        NavigationManager UriHelper { get; set; }
-        IJSRuntime JSRuntime { get; set; }
+        NavigationManager? UriHelper { get; set; }
+        IJSRuntime? JSRuntime { get; set; }
 
         /// <summary>
         /// Initializes a new instance of the <see cref="DialogService"/> class.
         /// </summary>
         /// <param name="uriHelper">The URI helper.</param>
         /// <param name="jsRuntime">IJSRuntime instance.</param>
-        public DialogService(NavigationManager uriHelper, IJSRuntime jsRuntime)
+        public DialogService(NavigationManager? uriHelper, IJSRuntime? jsRuntime)
         {
             UriHelper = uriHelper;
             JSRuntime = jsRuntime;
@@ -78,9 +78,9 @@ namespace Radzen
             }
         }
 
-        private void UriHelper_OnLocationChanged(object sender, Microsoft.AspNetCore.Components.Routing.LocationChangedEventArgs e)
+        private void UriHelper_OnLocationChanged(object? sender, Microsoft.AspNetCore.Components.Routing.LocationChangedEventArgs e)
         {
-            while (dialogs.Any())
+            while (dialogs.Count > 0)
             {
                 Close();
             }
@@ -94,27 +94,27 @@ namespace Radzen
         /// <summary>
         /// Raises the Close event.
         /// </summary>
-        public event Action<dynamic> OnClose;
+        public event Action<dynamic>? OnClose;
 
         /// <summary>
         /// Occurs when [on refresh].
         /// </summary>
-        public event Action OnRefresh;
+        public event Action? OnRefresh;
 
         /// <summary>
         /// Occurs when a new dialog is open.
         /// </summary>
-        public event Action<string, Type, Dictionary<string, object>, DialogOptions> OnOpen;
+        public event Action<string?, Type, Dictionary<string, object>, DialogOptions>? OnOpen;
 
         /// <summary>
         /// Raises the Close event for the side dialog
         /// </summary>
-        public event Action<dynamic> OnSideClose;
+        public event Action<dynamic>? OnSideClose;
 
         /// <summary>
         /// Raises the Open event for the side dialog
         /// </summary>
-        public event Action<Type, Dictionary<string, object>, SideDialogOptions> OnSideOpen;
+        public event Action<Type, Dictionary<string, object>, SideDialogOptions>? OnSideOpen;
 
         /// <summary>
         /// Opens a dialog with the specified arguments.
@@ -123,7 +123,7 @@ namespace Radzen
         /// <param name="title">The text displayed in the title bar of the dialog.</param>
         /// <param name="parameters">The dialog parameters.</param>
         /// <param name="options">The dialog options.</param>
-        public virtual void Open<T>(string title, Dictionary<string, object> parameters = null, DialogOptions options = null) where T : ComponentBase
+        public virtual void Open<T>(string title, Dictionary<string, object>? parameters = null, DialogOptions? options = null) where T : ComponentBase
         {
             OpenDialog<T>(title, parameters, options);
         }
@@ -135,7 +135,7 @@ namespace Radzen
         /// <param name="componentType">The type of the component to be displayed in the dialog. Must inherit from <see cref="ComponentBase"/>.</param>
         /// <param name="parameters">The dialog parameters.</param>
         /// <param name="options">The dialog options.</param>
-        public virtual void Open(string title, Type componentType, Dictionary<string, object> parameters = null, DialogOptions options = null)
+        public virtual void Open(string title, Type componentType, Dictionary<string, object>? parameters = null, DialogOptions? options = null)
         {
             if (!typeof(ComponentBase).IsAssignableFrom(componentType))
             {
@@ -143,8 +143,12 @@ namespace Radzen
             }
 
             var method = GetType().GetMethod(nameof(OpenDialog), BindingFlags.Instance | BindingFlags.NonPublic);
+            if (method == null)
+            {
+                throw new InvalidOperationException("OpenDialog method not found.");
+            }
 
-            method.MakeGenericMethod(componentType).Invoke(this, new object[] { title, parameters, options });
+            method.MakeGenericMethod(componentType).Invoke(this, new object[] { title, parameters!, options! });
         }
 
         /// <summary>
@@ -159,7 +163,7 @@ namespace Radzen
         /// The tasks
         /// </summary>
         protected List<TaskCompletionSource<dynamic>> tasks = new List<TaskCompletionSource<dynamic>>();
-        private TaskCompletionSource<dynamic> sideDialogResultTask;
+        private TaskCompletionSource<dynamic>? sideDialogResultTask;
 
         /// <summary>
         /// Opens a dialog with the specified arguments.
@@ -169,7 +173,7 @@ namespace Radzen
         /// <param name="parameters">The dialog parameters. Passed as property values of <typeparamref name="T" />.</param>
         /// <param name="options">The dialog options.</param>
         /// <returns>The value passed as argument to <see cref="Close" />.</returns>
-        public virtual Task<dynamic> OpenAsync<T>(string title, Dictionary<string, object> parameters = null, DialogOptions options = null) where T : ComponentBase
+        public virtual Task<dynamic> OpenAsync<T>(string title, Dictionary<string, object>? parameters = null, DialogOptions? options = null) where T : ComponentBase
         {
             var task = new TaskCompletionSource<dynamic>();
             tasks.Add(task);
@@ -188,7 +192,7 @@ namespace Radzen
         /// <param name="options">The dialog options.</param>
         /// <returns>A task that represents the result passed as an argument to <see cref="Close"/>.</returns>
         /// <exception cref="ArgumentException">Thrown if <paramref name="componentType"/> does not inherit from <see cref="ComponentBase"/>.</exception>
-        public virtual Task<dynamic> OpenAsync(string title, Type componentType, Dictionary<string, object> parameters = null, DialogOptions options = null)
+        public virtual Task<dynamic> OpenAsync(string title, Type componentType, Dictionary<string, object>? parameters = null, DialogOptions? options = null)
         {
             if (!typeof(ComponentBase).IsAssignableFrom(componentType))
             {
@@ -199,8 +203,12 @@ namespace Radzen
             tasks.Add(task);
 
             var method = GetType().GetMethod(nameof(OpenDialog), BindingFlags.Instance | BindingFlags.NonPublic);
+            if (method == null)
+            {
+                throw new InvalidOperationException("OpenDialog method not found.");
+            }
 
-            method.MakeGenericMethod(componentType).Invoke(this, new object[] { title, parameters, options });
+            method.MakeGenericMethod(componentType).Invoke(this, new object[] { title, parameters!, options! });
 
             return task.Task;
         }
@@ -214,7 +222,7 @@ namespace Radzen
         /// <param name="parameters">The dialog parameters. Passed as property values of <typeparamref name="T"/></param>
         /// <param name="options">The side dialog options.</param>
         /// <returns>A task that completes when the dialog is closed or a new one opened</returns>
-        public Task<dynamic> OpenSideAsync<T>(string title, Dictionary<string, object> parameters = null, SideDialogOptions options = null)
+        public Task<dynamic> OpenSideAsync<T>(string title, Dictionary<string, object>? parameters = null, SideDialogOptions? options = null)
             where T : ComponentBase
         {
             CloseSide();
@@ -238,7 +246,7 @@ namespace Radzen
         /// <param name="options">The side dialog options.</param>
         /// <returns>A task that represents the result passed as an argument to <see cref="CloseSide"/>.</returns>
         /// <exception cref="ArgumentException">Thrown if <paramref name="componentType"/> does not inherit from <see cref="ComponentBase"/>.</exception>
-        public Task<dynamic> OpenSideAsync(string title, Type componentType, Dictionary<string, object> parameters = null, SideDialogOptions options = null)
+        public Task<dynamic> OpenSideAsync(string title, Type componentType, Dictionary<string, object>? parameters = null, SideDialogOptions? options = null)
         {
             if (!typeof(ComponentBase).IsAssignableFrom(componentType))
             {
@@ -267,7 +275,7 @@ namespace Radzen
         /// <param name="title">The text displayed in the title bar of the side dialog.</param>
         /// <param name="parameters">The dialog parameters. Passed as property values of <typeparamref name="T"/></param>
         /// <param name="options">The side dialog options.</param>
-        public void OpenSide<T>(string title, Dictionary<string, object> parameters = null, SideDialogOptions options = null)
+        public void OpenSide<T>(string title, Dictionary<string, object>? parameters = null, SideDialogOptions? options = null)
             where T : ComponentBase
         {
             CloseSide();
@@ -289,7 +297,7 @@ namespace Radzen
         /// <param name="parameters">The dialog parameters, passed as property values of the specified component.</param>
         /// <param name="options">The side dialog options.</param>
         /// <exception cref="ArgumentException">Thrown if <paramref name="componentType"/> does not inherit from <see cref="ComponentBase"/>.</exception>
-        public void OpenSide(string title, Type componentType, Dictionary<string, object> parameters = null, SideDialogOptions options = null)
+        public void OpenSide(string title, Type componentType, Dictionary<string, object>? parameters = null, SideDialogOptions? options = null)
         {
             if (!typeof(ComponentBase).IsAssignableFrom(componentType))
             {
@@ -312,7 +320,7 @@ namespace Radzen
         /// Closes the side dialog
         /// </summary>
         /// <param name="result">The result of the Dialog</param>
-        public virtual void CloseSide(dynamic result = null)
+        public virtual void CloseSide(dynamic? result = null)
         {
             if (sideDialogResultTask?.Task.IsCompleted == false)
             {
@@ -322,7 +330,7 @@ namespace Radzen
             OnSideClose?.Invoke(result);
         }
 
-        private TaskCompletionSource sideDialogCloseTask;
+        private TaskCompletionSource? sideDialogCloseTask;
 
         internal void OnSideCloseComplete()
         {
@@ -334,7 +342,7 @@ namespace Radzen
         /// Closes the side dialog and waits for the closing animation to finish.
         /// </summary>
         /// <param name="result">The result of the Dialog</param>
-        public async Task CloseSideAsync(dynamic result = null)
+        public async Task CloseSideAsync(dynamic? result = null)
         {
             sideDialogCloseTask = new TaskCompletionSource();
 
@@ -351,7 +359,7 @@ namespace Radzen
         /// <param name="options">The dialog options.</param>
         /// <param name="cancellationToken">The cancellation token.</param>
         /// <returns>The value passed as argument to <see cref="Close" />.</returns>
-        public virtual Task<dynamic> OpenAsync(string title, RenderFragment<DialogService> childContent, DialogOptions options = null, CancellationToken? cancellationToken = null)
+        public virtual Task<dynamic> OpenAsync(string title, RenderFragment<DialogService> childContent, DialogOptions? options = null, CancellationToken? cancellationToken = null)
         {
             var task = new TaskCompletionSource<dynamic>();
 
@@ -377,7 +385,7 @@ namespace Radzen
         /// <param name="options">The dialog options.</param>
         /// <param name="cancellationToken">The cancellation token.</param>
         /// <returns>The value passed as argument to <see cref="Close" />.</returns>
-        public virtual Task<dynamic> OpenAsync(RenderFragment<DialogService> titleContent, RenderFragment<DialogService> childContent, DialogOptions options = null, CancellationToken? cancellationToken = null)
+        public virtual Task<dynamic> OpenAsync(RenderFragment<DialogService> titleContent, RenderFragment<DialogService> childContent, DialogOptions? options = null, CancellationToken? cancellationToken = null)
         {
             var task = new TaskCompletionSource<dynamic>();
 
@@ -402,7 +410,7 @@ namespace Radzen
         /// <param name="title">The text displayed in the title bar of the dialog.</param>
         /// <param name="childContent">The content displayed in the dialog.</param>
         /// <param name="options">The dialog options.</param>
-        public virtual void Open(string title, RenderFragment<DialogService> childContent, DialogOptions options = null)
+        public virtual void Open(string title, RenderFragment<DialogService> childContent, DialogOptions? options = null)
         {
             options = options ?? new DialogOptions();
 
@@ -416,12 +424,13 @@ namespace Radzen
         /// </summary>
         protected List<object> dialogs = new List<object>();
 
-        internal void OpenDialog<T>(string title, Dictionary<string, object> parameters, DialogOptions options)
+        internal void OpenDialog<T>(string? title, Dictionary<string, object>? parameters, DialogOptions? options)
         {
             dialogs.Add(new object());
 
             // Validate and set default values for the dialog options
             options ??= new();
+            parameters ??= new Dictionary<string, object>();
             options.Width = !String.IsNullOrEmpty(options.Width) ? options.Width : "600px";
             options.Left = !String.IsNullOrEmpty(options.Left) ? options.Left : "";
             options.Top = !String.IsNullOrEmpty(options.Top) ? options.Top : "";
@@ -440,7 +449,7 @@ namespace Radzen
         /// </summary>
         /// <param name="result">The result.</param>
         [JSInvokable("DialogService.Close")]
-        public virtual void Close(dynamic result = null)
+        public virtual void Close(dynamic? result = null)
         {
             var dialog = dialogs.LastOrDefault();
 
@@ -464,7 +473,7 @@ namespace Radzen
             reference?.Dispose();
             reference = null;
 
-            UriHelper.LocationChanged -= UriHelper_OnLocationChanged;
+            UriHelper?.LocationChanged -= UriHelper_OnLocationChanged;
         }
 
         /// <summary>
@@ -475,7 +484,7 @@ namespace Radzen
         /// <param name="options">The options.</param>
         /// <param name="cancellationToken">The cancellation token.</param>
         /// <returns><c>true</c> if the user clicked the OK button, <c>false</c> otherwise.</returns>
-        public virtual async Task<bool?> Confirm(string message = "Confirm?", string title = "Confirm", ConfirmOptions options = null, CancellationToken? cancellationToken = null)
+        public virtual async Task<bool?> Confirm(string message = "Confirm?", string title = "Confirm", ConfirmOptions? options = null, CancellationToken? cancellationToken = null)
         {
             // Validate and set default values for the dialog options
             options ??= new();
@@ -524,7 +533,7 @@ namespace Radzen
         /// <param name="options">The options.</param>
         /// <param name="cancellationToken">The cancellation token.</param>
         /// <returns><c>true</c> if the user clicked the OK button, <c>false</c> otherwise.</returns>
-        public virtual async Task<bool?> Confirm(RenderFragment message, string title = "Confirm", ConfirmOptions options = null, CancellationToken? cancellationToken = null)
+        public virtual async Task<bool?> Confirm(RenderFragment message, string title = "Confirm", ConfirmOptions? options = null, CancellationToken? cancellationToken = null)
         {
             // Validate and set default values for the dialog options
             options ??= new();
@@ -573,7 +582,7 @@ namespace Radzen
         /// <param name="options">The options.</param>
         /// <param name="cancellationToken">The cancellation token.</param>
         /// <returns><c>true</c> if the user clicked the OK button, <c>false</c> otherwise.</returns>
-        public virtual async Task<bool?> Alert(string message = "", string title = "Message", AlertOptions options = null, CancellationToken? cancellationToken = null)
+        public virtual async Task<bool?> Alert(string message = "", string title = "Message", AlertOptions? options = null, CancellationToken? cancellationToken = null)
         {
             // Validate and set default values for the dialog options
             options ??= new();
@@ -616,7 +625,7 @@ namespace Radzen
         /// <param name="options">The options.</param>
         /// <param name="cancellationToken">The cancellation token.</param>
         /// <returns><c>true</c> if the user clicked the OK button, <c>false</c> otherwise.</returns>
-        public virtual async Task<bool?> Alert(RenderFragment message, string title = "Message", AlertOptions options = null, CancellationToken? cancellationToken = null)
+        public virtual async Task<bool?> Alert(RenderFragment message, string title = "Message", AlertOptions? options = null, CancellationToken? cancellationToken = null)
         {
             // Validate and set default values for the dialog options
             options ??= new();
@@ -660,7 +669,7 @@ namespace Radzen
         /// <summary>
         /// Occurs when a property value changes.
         /// </summary>
-        public event PropertyChangedEventHandler PropertyChanged;
+        public event PropertyChangedEventHandler? PropertyChanged;
 
         /// <summary>
         /// Raises the <see cref="PropertyChanged" /> event.
@@ -707,12 +716,12 @@ namespace Radzen
             }
         }
 
-        private string width;
+        private string? width;
         /// <summary>
         /// Gets or sets the width of the dialog.
         /// </summary>
         /// <value>The width.</value>
-        public string Width
+        public string? Width
         {
             get => width;
             set
@@ -725,12 +734,12 @@ namespace Radzen
             }
         }
 
-        private string height;
+        private string? height;
         /// <summary>
         /// Gets or sets the height of the dialog.
         /// </summary>
         /// <value>The height.</value>
-        public string Height
+        public string? Height
         {
             get => height;
             set
@@ -743,12 +752,12 @@ namespace Radzen
             }
         }
 
-        private string style;
+        private string? style;
         /// <summary>
         /// Gets or sets the CSS style of the dialog
         /// </summary>
         /// <value>The style.</value>
-        public string Style
+        public string? Style
         {
             get => style;
             set
@@ -761,7 +770,7 @@ namespace Radzen
             }
         }
 
-        private bool closeDialogOnOverlayClick = false;
+        private bool closeDialogOnOverlayClick;
         /// <summary>
         /// Gets or sets a value indicating whether the dialog should be closed by clicking the overlay.
         /// </summary>
@@ -779,11 +788,11 @@ namespace Radzen
             }
         }
 
-        private string cssClass;
+        private string? cssClass;
         /// <summary>
         /// Gets or sets dialog box custom class
         /// </summary>
-        public string CssClass
+        public string? CssClass
         {
             get => cssClass;
             set
@@ -796,11 +805,11 @@ namespace Radzen
             }
         }
 
-        private string wrapperCssClass;
+        private string? wrapperCssClass;
         /// <summary>
         /// Gets or sets the CSS classes added to the dialog's wrapper element.
         /// </summary>
-        public string WrapperCssClass
+        public string? WrapperCssClass
         {
             get => wrapperCssClass;
             set
@@ -813,11 +822,11 @@ namespace Radzen
             }
         }
 
-        private string contentCssClass;
+        private string? contentCssClass;
         /// <summary>
         /// Gets or sets the CSS classes added to the dialog's content element.
         /// </summary>
-        public string ContentCssClass
+        public string? ContentCssClass
         {
             get => contentCssClass;
             set
@@ -830,7 +839,7 @@ namespace Radzen
             }
         }
 
-        private int closeTabIndex = 0;
+        private int closeTabIndex;
         /// <summary>
         /// Gets or sets a value the dialog escape tabindex. Set to <c>0</c> by default.
         /// </summary>
@@ -847,14 +856,14 @@ namespace Radzen
             }
         }
 
-        private RenderFragment<DialogService> titleContent;
+        private RenderFragment<DialogService>? titleContent;
         private bool resizable;
 
         /// <summary>
         /// Gets or sets the title content.
         /// </summary>
         /// <value>The title content.</value>
-        public RenderFragment<DialogService> TitleContent
+        public RenderFragment<DialogService>? TitleContent
         {
             get => titleContent;
             set
@@ -890,12 +899,12 @@ namespace Radzen
     /// </summary>
     public class SideDialogOptions : DialogOptionsBase
     {
-        private string title;
+        private string? title;
 
         /// <summary>
         /// The title displayed on the dialog.
         /// </summary>
-        public string Title
+        public string? Title
         {
             get => title;
             set
@@ -945,7 +954,7 @@ namespace Radzen
             }
         }
 
-        private bool autoFocusFirstElement = false;
+        private bool autoFocusFirstElement;
 
         /// <summary>
         /// Gets or sets a value indicating whether to focus the first focusable HTML element. Set to <c>true</c> by default.
@@ -1061,26 +1070,26 @@ namespace Radzen
         /// </summary>
         /// <value>The icon.</value>
 
-        public string Icon { get; set; }
+        public string? Icon { get; set; }
         /// <summary>
         /// Gets or sets the icon color in Title.
         /// </summary>
         /// <value>The icon color.</value>
 
-        public string IconColor { get; set; }
+        public string? IconColor { get; set; }
 
         /// <summary>
         /// Gets or sets the CSS style of the Icon in Title.
         /// </summary>
         public string IconStyle { get; set; } = "margin-right: 0.75rem";
 
-        private Action<Size> resize;
+        private Action<Size>? resize;
 
         /// <summary>
         /// Gets or sets the change.
         /// </summary>
         /// <value>The change.</value>
-        public Action<Size> Resize
+        public Action<Size>? Resize
         {
             get => resize;
             set
@@ -1112,13 +1121,13 @@ namespace Radzen
             }
         }
 
-        private Action<Point> drag;
+        private Action<Point>? drag;
 
         /// <summary>
         /// Gets or sets the change.
         /// </summary>
         /// <value>The change.</value>
-        public Action<Point> Drag
+        public Action<Point>? Drag
         {
             get => drag;
             set
@@ -1131,13 +1140,13 @@ namespace Radzen
             }
         }
 
-        private string left;
+        private string? left;
 
         /// <summary>
         /// Gets or sets the X coordinate of the dialog. Maps to the <c>left</c> CSS attribute.
         /// </summary>
         /// <value>The left.</value>
-        public string Left
+        public string? Left
         {
             get => left;
             set
@@ -1150,13 +1159,13 @@ namespace Radzen
             }
         }
 
-        private string top;
+        private string? top;
 
         /// <summary>
         /// Gets or sets the Y coordinate of the dialog. Maps to the <c>top</c> CSS attribute.
         /// </summary>
         /// <value>The top.</value>
-        public string Top
+        public string? Top
         {
             get => top;
             set
@@ -1169,13 +1178,13 @@ namespace Radzen
             }
         }
 
-        private string bottom;
+        private string? bottom;
 
         /// <summary>
         /// Specifies the <c>bottom</c> CSS attribute.
         /// </summary>
         /// <value>The bottom.</value>
-        public string Bottom
+        public string? Bottom
         {
             get => bottom;
             set
@@ -1188,13 +1197,13 @@ namespace Radzen
             }
         }
 
-        private RenderFragment<DialogService> childContent;
+        private RenderFragment<DialogService>? childContent;
 
         /// <summary>
         /// Gets or sets the child content.
         /// </summary>
         /// <value>The child content.</value>
-        public RenderFragment<DialogService> ChildContent
+        public RenderFragment<DialogService>? ChildContent
         {
             get => childContent;
             set
@@ -1251,12 +1260,12 @@ namespace Radzen
     /// </summary>
     public class AlertOptions : DialogOptions
     {
-        private string okButtonText;
+        private string? okButtonText;
 
         /// <summary>
         /// Gets or sets the text of the OK button.
         /// </summary>
-        public string OkButtonText
+        public string? OkButtonText
         {
             get => okButtonText;
             set
@@ -1275,12 +1284,12 @@ namespace Radzen
     /// </summary>
     public class ConfirmOptions : AlertOptions
     {
-        private string cancelButtonText;
+        private string? cancelButtonText;
 
         /// <summary>
         /// Gets or sets the text of the Cancel button.
         /// </summary>
-        public string CancelButtonText
+        public string? CancelButtonText
         {
             get => cancelButtonText;
             set
@@ -1299,13 +1308,13 @@ namespace Radzen
     /// </summary>
     public class Dialog : INotifyPropertyChanged
     {
-        private string title;
+        private string? title;
 
         /// <summary>
         /// Gets or sets the title.
         /// </summary>
         /// <value>The title.</value>
-        public string Title
+        public string? Title
         {
             get => title;
             set
@@ -1318,13 +1327,13 @@ namespace Radzen
             }
         }
 
-        private Type type;
+        private Type? type;
 
         /// <summary>
         /// Gets or sets the type.
         /// </summary>
         /// <value>The type.</value>
-        public Type Type
+        public Type? Type
         {
             get => type;
             set
@@ -1337,13 +1346,13 @@ namespace Radzen
             }
         }
 
-        private Dictionary<string, object> parameters;
+        private Dictionary<string, object>? parameters;
 
         /// <summary>
         /// Gets or sets the parameters.
         /// </summary>
         /// <value>The parameters.</value>
-        public Dictionary<string, object> Parameters
+        public Dictionary<string, object>? Parameters
         {
             get => parameters;
             set
@@ -1356,13 +1365,13 @@ namespace Radzen
             }
         }
 
-        private DialogOptions options;
+        private DialogOptions? options;
 
         /// <summary>
         /// Gets or sets the options.
         /// </summary>
         /// <value>The options.</value>
-        public DialogOptions Options
+        public DialogOptions? Options
         {
             get => options;
             set
@@ -1378,7 +1387,7 @@ namespace Radzen
         /// <summary>
         /// Occurs when a property value changes.
         /// </summary>
-        public event PropertyChangedEventHandler PropertyChanged;
+        public event PropertyChangedEventHandler? PropertyChanged;
 
         /// <summary>
         /// Raises the <see cref="PropertyChanged"/> event.

Radzen.Blazor/Directory.Build.props

@@ -0,0 +1,73 @@
+<Project>
+  <!-- 
+    Common build properties for all projects in the Radzen.Blazor solution.
+    
+    To use this file:
+    1. Rename to Directory.Build.props (remove .sample extension)
+    2. Adjust settings based on your needs
+    3. Review the analyzer settings in .editorconfig
+    
+    This file will be automatically imported by all projects in subdirectories.
+  -->
+
+  <PropertyGroup Label="Language Configuration">
+    <!-- Use latest C# language features -->
+    <LangVersion>latest</LangVersion>
+    
+    <!-- Do NOT enable implicit usings - explicit imports preferred for library code -->
+    <ImplicitUsings>disable</ImplicitUsings>
+    
+    <Nullable>enable</Nullable>
+    <NoWarn>CA2007</NoWarn>
+  </PropertyGroup>
+
+  <PropertyGroup Label="Code Analysis Configuration">
+    <!-- Enable .NET code analyzers -->
+    <AnalysisLevel>latest</AnalysisLevel>
+    <EnableNETAnalyzers>true</EnableNETAnalyzers>
+    
+    <!-- Run analyzers during build and in IDE -->
+    <RunAnalyzersDuringBuild>true</RunAnalyzersDuringBuild>
+    <RunAnalyzersDuringLiveAnalysis>true</RunAnalyzersDuringLiveAnalysis>
+    
+    <!-- Don't enforce code style in build (yet) - just show warnings -->
+    <EnforceCodeStyleInBuild>false</EnforceCodeStyleInBuild>
+    
+    <!-- Don't treat warnings as errors (yet) - too many to fix immediately -->
+    <TreatWarningsAsErrors>false</TreatWarningsAsErrors>
+    
+    <!-- Report all analyzer diagnostics -->
+    <AnalysisMode>All</AnalysisMode>
+  </PropertyGroup>
+
+  <PropertyGroup Label="Build Quality">
+    <!-- Enable deterministic builds for reproducibility -->
+    <Deterministic>true</Deterministic>
+    
+    <!-- Enable deterministic builds in CI/CD -->
+    <ContinuousIntegrationBuild Condition="'$(CI)' == 'true'">true</ContinuousIntegrationBuild>
+    
+    <!-- Embed source files for better debugging -->
+    <EmbedAllSources>true</EmbedAllSources>
+    <DebugType>embedded</DebugType>
+  </PropertyGroup>
+
+  <PropertyGroup Label="Demos and Tests Project Configuration" Condition="$(MSBuildProjectName.Contains('Demos')) OR $(MSBuildProjectName.Contains('Tests'))">
+    <!-- Demo projects and Tests should not be packable -->
+    <IsPackable>false</IsPackable>
+    
+    <!-- DISABLE ALL ANALYZERS FOR DEMO PROJECTS AND TESTS -->
+    <EnableNETAnalyzers>false</EnableNETAnalyzers>
+    <RunAnalyzersDuringBuild>false</RunAnalyzersDuringBuild>
+    <RunAnalyzersDuringLiveAnalysis>false</RunAnalyzersDuringLiveAnalysis>
+    <EnforceCodeStyleInBuild>false</EnforceCodeStyleInBuild>
+  </PropertyGroup>
+
+  <PropertyGroup Label="Performance">
+    <!-- Optimize startup time -->
+    <TieredCompilation>true</TieredCompilation>
+    <TieredCompilationQuickJit>true</TieredCompilationQuickJit>
+  </PropertyGroup>
+
+</Project>
+

Radzen.Blazor/DropDownBase.cs

@@ -1,7 +1,6 @@
 using Microsoft.AspNetCore.Components;
 using Microsoft.AspNetCore.Components.Rendering;
 using Microsoft.JSInterop;
-using Radzen.Blazor;
 using System;
 using System.Collections;
 using System.Collections.Generic;
@@ -22,12 +21,12 @@ namespace Radzen
         [Parameter]
         public int VirtualizationOverscanCount { get; set; }
 
-        internal Microsoft.AspNetCore.Components.Web.Virtualization.Virtualize<object> virtualize;
+        internal Microsoft.AspNetCore.Components.Web.Virtualization.Virtualize<object>? virtualize;
 
         /// <summary>
         /// The Virtualize instance.
         /// </summary>
-        public Microsoft.AspNetCore.Components.Web.Virtualization.Virtualize<object> Virtualize
+        public Microsoft.AspNetCore.Components.Web.Virtualization.Virtualize<object>? Virtualize
         {
             get
             {
@@ -35,12 +34,12 @@ namespace Radzen
             }
         }
 
-        List<object> virtualItems;
+        List<object>? virtualItems;
 
         private async ValueTask<Microsoft.AspNetCore.Components.Web.Virtualization.ItemsProviderResult<object>> LoadItems(Microsoft.AspNetCore.Components.Web.Virtualization.ItemsProviderRequest request)
         {
             var data = Data != null ? Data.Cast<object>() : Enumerable.Empty<object>();
-            var view = (LoadData.HasDelegate ? data : View).Cast<object>().AsQueryable();
+            var view = (LoadData.HasDelegate ? data : View)?.Cast<object>().AsQueryable() ?? Enumerable.Empty<object>().AsQueryable();
             var totalItemsCount = LoadData.HasDelegate ? Count : view.Count();
             var top = request.Count;
 
@@ -54,7 +53,7 @@ namespace Radzen
                 await LoadData.InvokeAsync(new Radzen.LoadDataArgs() { Skip = request.StartIndex, Top = top, Filter = searchText });
             }
 
-            virtualItems = (LoadData.HasDelegate ? Data : view.Skip(request.StartIndex).Take(top)).Cast<object>().ToList();
+            virtualItems = (LoadData.HasDelegate ? (Data ?? Enumerable.Empty<object>()) : view.Skip(request.StartIndex).Take(top)).Cast<object>().ToList();
 
             return new Microsoft.AspNetCore.Components.Web.Virtualization.ItemsProviderResult<object>(virtualItems, LoadData.HasDelegate ? Count : totalItemsCount);
         }
@@ -105,13 +104,13 @@ namespace Radzen
                     builder.AddAttribute(1, "ItemsProvider", new Microsoft.AspNetCore.Components.Web.Virtualization.ItemsProviderDelegate<object>(LoadItems));
                     builder.AddAttribute(2, "ChildContent", (RenderFragment<object>)((context) =>
                     {
-                        return (RenderFragment)((b) =>
+                        return b =>
                         {
                             RenderItem(b, context);
-                        });
+                        };
                     }));
 
-                    if (VirtualizationOverscanCount != default(int))
+                    if (VirtualizationOverscanCount != default)
                     {
                         builder.AddAttribute(3, "OverscanCount", VirtualizationOverscanCount);
                     }
@@ -122,9 +121,13 @@ namespace Radzen
                 }
                 else
                 {
-                    foreach (var item in LoadData.HasDelegate ? Data : View)
+                    var items = LoadData.HasDelegate ? Data : View;
+                    if (items != null)
                     {
-                        RenderItem(builder, item);
+                        foreach (var item in items)
+                        {
+                            RenderItem(builder, item);
+                        }
                     }
                 }
             });
@@ -160,21 +163,18 @@ namespace Radzen
             //
         }
 
-        System.Collections.Generic.HashSet<object> keys = new System.Collections.Generic.HashSet<object>();
+        HashSet<object> keys = new HashSet<object>();
 
-        internal object GetKey(object item)
+        internal object? GetKey(object item)
         {
-            var value = GetItemOrValueFromProperty(item, ValueProperty);
+            var value = GetItemOrValueFromProperty(item, ValueProperty ?? string.Empty);
 
-            if (!keys.Contains(value))
+            if (value != null)
             {
                 keys.Add(value);
-                return value;
-            }
-            else
-            {
-                return item;
             }
+
+            return value;
         }
 
         /// <summary>
@@ -182,7 +182,7 @@ namespace Radzen
         /// </summary>
         /// <value>The header template.</value>
         [Parameter]
-        public RenderFragment HeaderTemplate { get; set; }
+        public RenderFragment? HeaderTemplate { get; set; }
 
         /// <summary>
         /// Gets or sets a value indicating whether filtering is allowed. Set to <c>false</c> by default.
@@ -231,21 +231,21 @@ namespace Radzen
         /// </summary>
         /// <value>The template.</value>
         [Parameter]
-        public RenderFragment<dynamic> Template { get; set; }
+        public RenderFragment<dynamic>? Template { get; set; }
 
         /// <summary>
         /// Gets or sets the value property.
         /// </summary>
         /// <value>The value property.</value>
         [Parameter]
-        public string ValueProperty { get; set; }
+        public string? ValueProperty { get; set; }
 
         /// <summary>
         /// Gets or sets the disabled property.
         /// </summary>
         /// <value>The disabled property.</value>
         [Parameter]
-        public string DisabledProperty { get; set; }
+        public string? DisabledProperty { get; set; }
 
         /// <summary>
         /// Gets or sets the remove chip button title.
@@ -282,7 +282,7 @@ namespace Radzen
         /// <summary>
         /// The selected item
         /// </summary>
-        protected object selectedItem = null;
+        protected object? selectedItem;
         Type GetItemType(IEnumerable items)
         {
             var firstType = items.Cast<object>().FirstOrDefault()?.GetType() ?? typeof(object);
@@ -301,7 +301,7 @@ namespace Radzen
         /// </summary>
         protected virtual async System.Threading.Tasks.Task SelectAll()
         {
-            if (Disabled)
+            if (Disabled || View == null)
             {
                 return;
             }
@@ -316,11 +316,14 @@ namespace Radzen
                 selectedItems.Clear();
             }
 
-            if (!string.IsNullOrEmpty(ValueProperty))
+            if (!string.IsNullOrEmpty(ValueProperty) && Data != null)
             {
                 var elementType = PropertyAccess.GetElementType(Data.GetType());
-                System.Reflection.PropertyInfo pi = PropertyAccess.GetProperty(elementType, ValueProperty);
-                internalValue = selectedItems.Select(i => GetItemOrValueFromProperty(i, ValueProperty)).AsQueryable().Cast(pi.PropertyType);
+                System.Reflection.PropertyInfo? pi = PropertyAccess.GetProperty(elementType, ValueProperty);
+                if (pi != null)
+                {
+                    internalValue = selectedItems.Select(i => GetItemOrValueFromProperty(i, ValueProperty)).AsQueryable().Cast(pi.PropertyType);
+                }
             }
             else
             {
@@ -329,25 +332,34 @@ namespace Radzen
                 internalValue = selectedItems.AsQueryable().Cast(type);
             }
 
-            await collectionAssignment.MakeAssignment((IEnumerable)internalValue, ValueChanged);
+            if (internalValue != null)
+            {
+                await collectionAssignment.MakeAssignment((IEnumerable)internalValue, ValueChanged);
+            }
             if (FieldIdentifier.FieldName != null) { EditContext?.NotifyFieldChanged(FieldIdentifier); }
             await Change.InvokeAsync(internalValue);
 
             StateHasChanged();
 
-            await JSRuntime.InvokeVoidAsync("Radzen.focusElement", GetId());
+            if (JSRuntime != null)
+            {
+                await JSRuntime.InvokeVoidAsync("Radzen.focusElement", GetId());
+            }
         }
 
         internal bool IsAllSelected()
         {
-            List<object> notDisabledItemsInList = View.Cast<object>().ToList()
+            List<object> notDisabledItemsInList = View != null ? View.Cast<object>().ToList()
                 .Where(i => disabledPropertyGetter == null || disabledPropertyGetter(i) as bool? != true)
-                .ToList();
+                .ToList() : new List<object>();
 
             if (LoadData.HasDelegate && !string.IsNullOrEmpty(ValueProperty))
             {
                 return View != null && notDisabledItemsInList.Count > 0 && notDisabledItemsInList
-                    .All(i => IsItemSelectedByValue(GetItemOrValueFromProperty(i, ValueProperty)));
+                    .All(i => { 
+                        var value = GetItemOrValueFromProperty(i, ValueProperty);
+                        return value != null ? IsItemSelectedByValue(value) : false;
+                    });
             }
 
             return View != null && notDisabledItemsInList.Count > 0 && selectedItems.Count == notDisabledItemsInList.Count;
@@ -365,14 +377,17 @@ namespace Radzen
         /// <summary>
         /// Clears all.
         /// </summary>
-        protected async System.Threading.Tasks.Task ClearAll()
+        protected async Task ClearAll()
         {
             if (Disabled)
                 return;
 
             searchText = null;
             await SearchTextChanged.InvokeAsync(searchText);
-            await JSRuntime.InvokeAsync<string>("Radzen.setInputValue", search, "");
+            if (JSRuntime != null)
+            {
+                await JSRuntime.InvokeAsync<string>("Radzen.setInputValue", search, "");
+            }
 
             internalValue = collectionAssignment.GetCleared();
             selectedItem = null;
@@ -381,7 +396,7 @@ namespace Radzen
 
             selectedIndex = -1;
 
-            await ValueChanged.InvokeAsync((T)internalValue);
+            await ValueChanged.InvokeAsync(internalValue != null ? (T)internalValue : default(T)!);
             if (FieldIdentifier.FieldName != null) { EditContext?.NotifyFieldChanged(FieldIdentifier); }
             await Change.InvokeAsync(internalValue);
 
@@ -393,14 +408,14 @@ namespace Radzen
         /// <summary>
         /// The data
         /// </summary>
-        IEnumerable _data;
+        IEnumerable? _data;
 
         /// <summary>
         /// Gets or sets the data.
         /// </summary>
         /// <value>The data.</value>
         [Parameter]
-        public override IEnumerable Data
+        public override IEnumerable? Data
         {
             get
             {
@@ -466,22 +481,26 @@ namespace Radzen
             }
         }
 
-        Func<object, object> GetGetter(string propertyName, Type type)
+        Func<object, object?> GetGetter(string propertyName, Type type)
         {
-            if (propertyName?.Contains("[") == true)
+            if (propertyName?.Contains('[', StringComparison.Ordinal) == true)
             {
                 var getter = typeof(PropertyAccess).GetMethod("Getter", [typeof(string), typeof(Type)]);
+                if (getter == null)
+                {
+                    return PropertyAccess.Getter<object, object?>(propertyName, type);
+                }
                 var getterMethod = getter.MakeGenericMethod([type, typeof(object)]);
 
-                return (i) => getterMethod.Invoke(i, [propertyName, type]);
+                return (i) => getterMethod.Invoke(i, [propertyName, type])!;
             }
 
-            return PropertyAccess.Getter<object, object>(propertyName, type);
+            return PropertyAccess.Getter<object, object?>(propertyName ?? string.Empty, type);
         }
 
-        internal Func<object, object> valuePropertyGetter;
-        internal Func<object, object> textPropertyGetter;
-        internal Func<object, object> disabledPropertyGetter;
+        internal Func<object, object?>? valuePropertyGetter;
+        internal Func<object, object?>? textPropertyGetter;
+        internal Func<object, object?>? disabledPropertyGetter;
 
         /// <summary>
         /// Gets the item or value from property.
@@ -489,7 +508,7 @@ namespace Radzen
         /// <param name="item">The item.</param>
         /// <param name="property">The property.</param>
         /// <returns>System.Object.</returns>
-        public object GetItemOrValueFromProperty(object item, string property)
+        public object? GetItemOrValueFromProperty(object? item, string property)
         {
             if (item != null)
             {
@@ -610,16 +629,19 @@ namespace Radzen
             if (Disabled)
                 return;
 
-            await JSRuntime.InvokeVoidAsync("Radzen.togglePopup", Element, PopupID, true);
-            await JSRuntime.InvokeVoidAsync("Radzen.focusElement", isFilter ? UniqueID : SearchID);
+            if (JSRuntime != null)
+            {
+                await JSRuntime.InvokeVoidAsync("Radzen.togglePopup", Element, PopupID, true);
+                await JSRuntime.InvokeVoidAsync("Radzen.focusElement", isFilter ? UniqueID : SearchID);
+            }
 
-            if (list != null)
+            if (list != null && JSRuntime != null)
             {
                 await JSRuntime.InvokeVoidAsync("Radzen.selectListItem", search, list, selectedIndex);
             }
         }
 
-        internal bool preventKeydown = false;
+        internal bool preventKeydown;
 
         /// <summary>
         /// Handles the key press.
@@ -627,9 +649,9 @@ namespace Radzen
         /// <param name="args">The <see cref="Microsoft.AspNetCore.Components.Web.KeyboardEventArgs"/> instance containing the event data.</param>
         /// <param name="isFilter">if set to <c>true</c> [is filter].</param>
         /// <param name="shouldSelectOnChange">Should select item on item change with keyboard.</param>
-        protected virtual async System.Threading.Tasks.Task HandleKeyPress(Microsoft.AspNetCore.Components.Web.KeyboardEventArgs args, bool isFilter = false, bool? shouldSelectOnChange = null)
+        protected virtual async Task HandleKeyPress(Microsoft.AspNetCore.Components.Web.KeyboardEventArgs args, bool isFilter = false, bool? shouldSelectOnChange = null)
         {
-            if (Disabled || Data == null)
+            if (Disabled || Data == null || args == null)
                 return;
 
             List<object> items = Enumerable.Empty<object>().ToList();
@@ -649,7 +671,7 @@ namespace Radzen
                 }
                 else
                 {
-                    items = View.Cast<object>().ToList();
+                    items = View != null ? View.Cast<object>().ToList() : Enumerable.Empty<object>().ToList();
                 }
             }
 
@@ -661,16 +683,19 @@ namespace Radzen
 
                 try
                 {
-                    selectedIndex = await JSRuntime.InvokeAsync<int>("Radzen.focusListItem", search, list, key == "ArrowDown" || key == "ArrowRight", selectedIndex);
-
-                    var popupOpened = await JSRuntime.InvokeAsync<bool>("Radzen.popupOpened", PopupID);
-
-                    if (!Multiple && !popupOpened && shouldSelectOnChange != false)
+                    if (JSRuntime != null)
                     {
-                        var itemToSelect = items.ElementAtOrDefault(selectedIndex);
-                        if (itemToSelect != null)
+                        selectedIndex = await JSRuntime.InvokeAsync<int>("Radzen.focusListItem", search, list, key == "ArrowDown" || key == "ArrowRight", selectedIndex);
+
+                        var popupOpened = await JSRuntime.InvokeAsync<bool>("Radzen.popupOpened", PopupID);
+
+                        if (!Multiple && !popupOpened && shouldSelectOnChange != false)
                         {
-                            await OnSelectItem(itemToSelect, true);
+                            var itemToSelect = items.ElementAtOrDefault(selectedIndex);
+                            if (itemToSelect != null)
+                            {
+                                await OnSelectItem(itemToSelect, true);
+                            }
                         }
                     }
                 }
@@ -683,37 +708,43 @@ namespace Radzen
             {
                 preventKeydown = true;
 
-                if (selectedIndex == -1 && items.Count() == 1)
+                if (selectedIndex == -1 && items.Count == 1)
                 {
                     selectedIndex = 0;
                 }
 
-                if (selectedIndex >= 0 && selectedIndex <= items.Count() - 1)
+                if (JSRuntime != null)
                 {
-                    var itemToSelect = items.ElementAtOrDefault(selectedIndex);
-
-                    await JSRuntime.InvokeAsync<string>("Radzen.setInputValue", search, $"{searchText}".Trim());
-
-                    if (itemToSelect != null)
+                    if (selectedIndex >= 0 && selectedIndex <= items.Count - 1)
                     {
-                        await OnSelectItem(itemToSelect, true);
+                        var itemToSelect = items.ElementAtOrDefault(selectedIndex);
+
+                        await JSRuntime.InvokeAsync<string>("Radzen.setInputValue", search, $"{searchText}".Trim());
+
+                        if (itemToSelect != null)
+                        {
+                            await OnSelectItem(itemToSelect, true);
+                        }
                     }
-                }
 
-                var popupOpened = await JSRuntime.InvokeAsync<bool>("Radzen.popupOpened", PopupID);
+                    var popupOpened = await JSRuntime.InvokeAsync<bool>("Radzen.popupOpened", PopupID);
 
-                if (!popupOpened)
-                {
-                    if(key != "Space")
+                    if (!popupOpened)
                     {
-                        await OpenPopup(key, isFilter);
+                        if (key != "Space")
+                        {
+                            await OpenPopup(key, isFilter);
+                        }
                     }
-                }
-                else
-                {
-                    if (!Multiple && (!isFilter || key != "Space"))
+                    else
                     {
-                        await ClosePopup(key);
+                        if (!Multiple && (!isFilter || key != "Space"))
+                        {
+                            if (!Multiple && !isFilter)
+                            {
+                                await ClosePopup(key);
+                            }
+                        }
                     }
                 }
             }
@@ -758,9 +789,20 @@ namespace Radzen
             else if (args.Key.Length == 1 && !args.CtrlKey && !args.AltKey && !args.ShiftKey)
             {
                 // searching for element
-                var filteredItems = Query.Where(TextProperty, args.Key, StringFilterOperator.StartsWith, FilterCaseSensitivity.CaseInsensitive)
-                    .Cast(Query.ElementType).Cast<dynamic>().ToList();
-
+                if (Query == null)
+                {
+                    return;
+                }
+                var query = Query;
+                var elementType = query.ElementType;
+                if (elementType == null)
+                {
+                    return;
+                }
+                var filteredItems = (!string.IsNullOrEmpty(TextProperty) ?
+                    query.Where(TextProperty, args.Key, StringFilterOperator.StartsWith, FilterCaseSensitivity.CaseInsensitive) :
+                    query)
+                    .Cast(elementType).Cast<dynamic>().ToList();
 
                 if (previousKey != args.Key)
                 {
@@ -768,7 +810,7 @@ namespace Radzen
                     itemIndex = -1;
                 }
 
-                itemIndex = itemIndex + 1 >= filteredItems.Count() ? 0 : itemIndex + 1;
+                itemIndex = itemIndex + 1 >= filteredItems.Count ? 0 : itemIndex + 1;
                 var itemToSelect = filteredItems.ElementAtOrDefault(itemIndex);
 
                 if (itemToSelect is not null)
@@ -785,7 +827,10 @@ namespace Radzen
                         {
                             selectedIndex = result.Index;
                         }
-                        await JSRuntime.InvokeVoidAsync("Radzen.selectListItem", list, list, result.Index);
+                        if (JSRuntime != null)
+                        {
+                            await JSRuntime.InvokeVoidAsync("Radzen.selectListItem", list, list, result.Index);
+                        }
                     }
                 }
 
@@ -795,14 +840,17 @@ namespace Radzen
 
         internal virtual async Task ClosePopup(string key)
         {
-            await JSRuntime.InvokeVoidAsync("Radzen.closePopup", PopupID);
+            if (JSRuntime != null)
+            {
+                await JSRuntime.InvokeVoidAsync("Radzen.closePopup", PopupID);
+            }
         }
 
         int itemIndex;
-        string previousKey;
+        string? previousKey;
 
         /// <summary>
-        /// Handles the <see cref="E:FilterKeyPress" /> event.
+        /// Handles the FilterKeyPress event.
         /// </summary>
         /// <param name="args">The <see cref="Microsoft.AspNetCore.Components.Web.KeyboardEventArgs"/> instance containing the event data.</param>
         protected virtual async System.Threading.Tasks.Task OnFilterKeyPress(Microsoft.AspNetCore.Components.Web.KeyboardEventArgs args)
@@ -852,13 +900,15 @@ namespace Radzen
 
             if (Multiple)
                 selectedIndex = -1;
-
-            await JSRuntime.InvokeAsync<string>("Radzen.repositionPopup", Element, PopupID);
+            if (JSRuntime != null)
+            {
+                await JSRuntime.InvokeAsync<string>("Radzen.repositionPopup", Element, PopupID);
+            }
             await InvokeAsync(() => SearchTextChanged.InvokeAsync(SearchText));
         }
 
         /// <summary>
-        /// Handles the <see cref="E:KeyPress" /> event.
+        /// Handles the KeyPress event.
         /// </summary>
         /// <param name="args">The <see cref="Microsoft.AspNetCore.Components.Web.KeyboardEventArgs"/> instance containing the event data.</param>
         /// <param name="shouldSelectOnChange">Should select item on item change with keyboard.</param>
@@ -872,13 +922,13 @@ namespace Radzen
         /// </summary>
         /// <param name="item">The item.</param>
         /// <param name="isFromKey">if set to <c>true</c> [is from key].</param>
-        protected virtual async System.Threading.Tasks.Task OnSelectItem(object item, bool isFromKey = false)
+        protected virtual async System.Threading.Tasks.Task OnSelectItem(object? item, bool isFromKey = false)
         {
             await SelectItem(item);
         }
 
         /// <summary>
-        /// Handles the <see cref="E:Filter" /> event.
+        /// Handles the Filter event.
         /// </summary>
         /// <param name="args">The <see cref="ChangeEventArgs"/> instance containing the event data.</param>
         protected virtual async System.Threading.Tasks.Task OnFilter(ChangeEventArgs args)
@@ -946,7 +996,7 @@ namespace Radzen
             if (valueChanged)
             {
                 internalValue = parameters.GetValueOrDefault<object>(nameof(Value));
-                if (PreserveCollectionOnSelection)
+                if (PreserveCollectionOnSelection && internalValue != null)
                 {
                     collectionAssignment = new ReferenceGenericCollectionAssignment((T)internalValue);
                 }
@@ -969,7 +1019,7 @@ namespace Radzen
             }
 
             var shouldClose = visibleChanged && !Visible;
-            if (shouldClose && !firstRender)
+            if (shouldClose && !firstRender && JSRuntime != null)
             {
                 await JSRuntime.InvokeVoidAsync("Radzen.destroyPopup", PopupID);
             }
@@ -991,18 +1041,24 @@ namespace Radzen
                 }
             }
 
-            SelectItemFromValue(internalValue);
+            if (internalValue != null)
+            {
+                SelectItemFromValue(internalValue);
+            }
 
             return base.OnParametersSetAsync();
         }
 
         /// <summary>
-        /// Handles the <see cref="E:Change" /> event.
+        /// Handles the Change event.
         /// </summary>
         /// <param name="args">The <see cref="ChangeEventArgs"/> instance containing the event data.</param>
         protected void OnChange(ChangeEventArgs args)
         {
-            internalValue = args.Value;
+            if (args != null)
+            {
+                internalValue = args.Value;
+            }
         }
 
         /// <summary>
@@ -1014,7 +1070,8 @@ namespace Radzen
         {
             if (!string.IsNullOrEmpty(ValueProperty))
             {
-                return IsItemSelectedByValue(GetItemOrValueFromProperty(item, ValueProperty));
+                var value = GetItemOrValueFromProperty(item, ValueProperty);
+                return value != null ? IsItemSelectedByValue(value) : false;
             }
             else
             {
@@ -1034,7 +1091,7 @@ namespace Radzen
         /// </summary>
         /// <value>The selected item.</value>
         [Parameter]
-        public object SelectedItem
+        public object? SelectedItem
         {
             get
             {
@@ -1072,13 +1129,13 @@ namespace Radzen
         /// Gets the view.
         /// </summary>
         /// <value>The view.</value>
-        protected override IEnumerable View
+        protected override IEnumerable? View
         {
             get
             {
                 if (_view == null && Query != null)
                 {
-                    _view = Query.Where(TextProperty, searchText, FilterOperator, FilterCaseSensitivity);
+                    _view = Query.Where(TextProperty ?? string.Empty, searchText, FilterOperator, FilterCaseSensitivity);
                 }
 
                 return _view;
@@ -1090,7 +1147,7 @@ namespace Radzen
         /// </summary>
         void SetSelectedIndexFromSelectedItem()
         {
-            if (selectedItem != null)
+            if (selectedItem != null && View != null)
             {
                 if (typeof(EnumerableQuery).IsAssignableFrom(View.GetType()))
                 {
@@ -1112,17 +1169,17 @@ namespace Radzen
         /// </summary>
         /// <param name="item">The item.</param>
         /// <param name="raiseChange">if set to <c>true</c> [raise change].</param>
-        internal async System.Threading.Tasks.Task SelectItemInternal(object item, bool raiseChange = true)
+        internal async Task SelectItemInternal(object item, bool raiseChange = true)
         {
             await SelectItem(item, raiseChange);
         }
 
-        internal object internalValue;
+        internal object? internalValue;
         
         /// <summary>
         /// Will add/remove selected items from a bound ICollection&lt;T&gt;, instead of replacing it.
         /// </summary>
-        protected bool PreserveCollectionOnSelection = false;
+        protected bool PreserveCollectionOnSelection;
         private DefaultCollectionAssignment collectionAssignment = new();
 
         /// <summary>
@@ -1130,7 +1187,7 @@ namespace Radzen
         /// </summary>
         /// <param name="item">The item.</param>
         /// <param name="raiseChange">if set to <c>true</c> [raise change].</param>
-        public async System.Threading.Tasks.Task SelectItem(object item, bool raiseChange = true)
+        public async Task SelectItem(object? item, bool raiseChange = true)
         {
             if (disabledPropertyGetter != null && item != null && disabledPropertyGetter(item) as bool? == true)
             {
@@ -1143,7 +1200,7 @@ namespace Radzen
                     return;
 
                 selectedItem = item;
-                if (!string.IsNullOrEmpty(ValueProperty))
+                if (!string.IsNullOrEmpty(ValueProperty) && item != null)
                 {
                     internalValue = PropertyAccess.GetItemOrValueFromProperty(item, ValueProperty);
                 }
@@ -1158,16 +1215,26 @@ namespace Radzen
             }
             else
             {
-                UpdateSelectedItems(item);
+                if (item != null)
+                {
+                    UpdateSelectedItems(item);
+                }
 
-                if (!string.IsNullOrEmpty(ValueProperty))
+                if (!string.IsNullOrEmpty(ValueProperty) && Data != null)
                 {
                     var elementType = PropertyAccess.GetElementType(Data.GetType());
-                    System.Reflection.PropertyInfo pi = PropertyAccess.GetProperty(elementType, ValueProperty);
-                    internalValue = selectedItems.Select(i => GetItemOrValueFromProperty(i, ValueProperty)).AsQueryable().Cast(pi.PropertyType);
+                    System.Reflection.PropertyInfo? pi = PropertyAccess.GetProperty(elementType, ValueProperty);
+                    if(pi != null)
+                    {
+                        internalValue = selectedItems.Select(i => GetItemOrValueFromProperty(i, ValueProperty)).AsQueryable().Cast(pi.PropertyType);
+                    }
                 }
                 else
                 {
+                    if (Data == null)
+                    {
+                        return;
+                    }
                     var query = Data.AsQueryable();
                     var elementType = query.ElementType;
 
@@ -1196,11 +1263,14 @@ namespace Radzen
                 {
                     if (Multiple)
                     {
-                        await collectionAssignment.MakeAssignment((IEnumerable)internalValue, ValueChanged);
+                        if (internalValue != null)
+                        {
+                            await collectionAssignment.MakeAssignment((IEnumerable)internalValue, ValueChanged);
+                        }
                     }
                     else
                     {
-                        await ValueChanged.InvokeAsync(internalValue != null ? (T)internalValue : default);
+                        await ValueChanged.InvokeAsync(internalValue != null ? (T)internalValue : default(T)!);
                     }
                 }
 
@@ -1212,7 +1282,7 @@ namespace Radzen
         }
 
         /// <inheritdoc />
-        public override object GetValue()
+        public override object? GetValue()
         {
             return internalValue;
         }
@@ -1223,7 +1293,7 @@ namespace Radzen
             {
                 var value = GetItemOrValueFromProperty(item, ValueProperty);
 
-                if (!IsItemSelectedByValue(value))
+                if (value != null && !IsItemSelectedByValue(value))
                 {
                     selectedItems.Add(item);
                 }
@@ -1292,7 +1362,7 @@ namespace Radzen
 
                                 if (typeof(EnumerableQuery).IsAssignableFrom(view.GetType()))
                                 {
-                                    item = view.OfType<object>().Where(i => object.Equals(GetItemOrValueFromProperty(i, ValueProperty), v)).FirstOrDefault();
+                                    item = view.OfType<object>().Where(i => object.Equals(GetItemOrValueFromProperty(i, ValueProperty), v)).FirstOrDefault()!;
                                 }
                                 else
                                 {
@@ -1305,7 +1375,7 @@ namespace Radzen
                                         }
                                     },
                                     LogicalFilterOperator.And,
-                                    FilterCaseSensitivity.Default).FirstOrDefault();
+                                    FilterCaseSensitivity.Default).FirstOrDefault()!;
                                 }
 
                                 if (!object.Equals(item, null) && !selectedItems.AsQueryable().Where(i => object.Equals(GetItemOrValueFromProperty(i, ValueProperty), v)).Any())
@@ -1330,7 +1400,7 @@ namespace Radzen
         /// <summary>
         /// For lists of objects, an IEqualityComparer to control how selected items are determined
         /// </summary>
-        [Parameter] public IEqualityComparer<object> ItemComparer { get; set; }
+        [Parameter] public IEqualityComparer<object>? ItemComparer { get; set; }
 
         internal bool IsItemSelectedByValue(object v)
         {
@@ -1353,6 +1423,8 @@ namespace Radzen
             base.Dispose();
 
             keys.Clear();
+
+            GC.SuppressFinalize(this);
         }
         
         private class DefaultCollectionAssignment
@@ -1363,42 +1435,55 @@ namespace Radzen
                 {
                     if (object.Equals(selectedItems, null))
                     {
-                        await valueChanged.InvokeAsync(default(T));
+                        await valueChanged.InvokeAsync(default(T)!);
                     }
                     else
                     {
-                        var list = (IList)Activator.CreateInstance(typeof(T));
-                        foreach (var i in (IEnumerable)selectedItems)
+                        var list = (IList?)Activator.CreateInstance<T>();
+                        if (list != null)
                         {
-                            list.Add(i);
+                            foreach (var i in (IEnumerable)selectedItems)
+                            {
+                                list.Add(i);
+                            }
+                            await valueChanged.InvokeAsync((T)(object)list);
+                        }
+                        else
+                        {
+                            await valueChanged.InvokeAsync(default(T)!);
                         }
-                        await valueChanged.InvokeAsync((T)(object)list);
                     }
                 }
                 else if (typeof(T).IsGenericType && typeof(ICollection<>).MakeGenericType(typeof(T).GetGenericArguments()[0]).IsAssignableFrom(typeof(T)))
                 {
                     if (object.Equals(selectedItems, null))
                     {
-                        await valueChanged.InvokeAsync(default(T));
+                        await valueChanged.InvokeAsync(default(T)!);
                     }
                     else
                     {
-
-                            var list = (IList)Activator.CreateInstance(typeof(List<>).MakeGenericType(typeof(T).GetGenericArguments()[0]));
+                        var list = (IList?)Activator.CreateInstance(typeof(List<>).MakeGenericType(typeof(T).GetGenericArguments()[0]));
+                        if (list != null)
+                        {
                             foreach (var i in (IEnumerable)selectedItems)
                             {
                                 list.Add(i);
                             }
                             await valueChanged.InvokeAsync((T)(object)list);
+                        }
+                        else
+                        {
+                            await valueChanged.InvokeAsync(default(T)!);
+                        }
                     }
                 }
                 else
                 {
-                    await valueChanged.InvokeAsync(object.Equals(selectedItems, null) ? default(T) : (T)selectedItems);
+                    await valueChanged.InvokeAsync(object.Equals(selectedItems, null) ? default(T)! : (T)selectedItems);
                 }
             }
 
-            public virtual T GetCleared()
+            public virtual T? GetCleared()
             {
                 return default(T);
             }
@@ -1408,9 +1493,9 @@ namespace Radzen
         {
             private readonly T originalCollection;
             private readonly bool canHandle;
-            private readonly System.Reflection.MethodInfo clearMethod;
-            private readonly System.Reflection.MethodInfo addMethod;
-            private readonly System.Reflection.MethodInfo removeMethod;
+            private readonly System.Reflection.MethodInfo? clearMethod;
+            private readonly System.Reflection.MethodInfo? addMethod;
+            private readonly System.Reflection.MethodInfo? removeMethod;
 
             public ReferenceGenericCollectionAssignment(T originalCollection)
             {
@@ -1437,34 +1522,34 @@ namespace Radzen
 
             public override async Task MakeAssignment(IEnumerable selectedItems, EventCallback<T> valueChanged)
             {
-                if (!canHandle)
+                if (!canHandle || originalCollection == null)
                 {
-                    // Fallback to default behavior when we can't handle the type
+                    // Fallback to default behavior when we can't handle the type or originalCollection is null
                     await base.MakeAssignment(selectedItems, valueChanged);
                     return;
                 }
 
                 var currentItems = selectedItems.Cast<object>().ToHashSet();
-                var existingItems = ((IEnumerable)originalCollection).Cast<object>().ToHashSet();
+                var existingItems = (originalCollection as IEnumerable)?.Cast<object>().ToHashSet() ?? new HashSet<object>();
                 foreach (var i in currentItems)
                 {
                     if (!existingItems.Contains(i))
-                        addMethod.Invoke(originalCollection, [i]);
+                        addMethod!.Invoke(originalCollection, [i]);
                 }
                 foreach (var i in existingItems)
                 {
                     if (!currentItems.Contains(i))
-                        removeMethod.Invoke(originalCollection, [i]);
+                        removeMethod!.Invoke(originalCollection, [i]);
                 }
 
                 await valueChanged.InvokeAsync(originalCollection);
             }
 
-            public override T GetCleared()
+            public override T? GetCleared()
             {
-                if (canHandle)
+                if (canHandle && originalCollection != null)
                 {
-                    clearMethod.Invoke(originalCollection, null);
+                    clearMethod!.Invoke(originalCollection, null);
                     return originalCollection;
                 }
                 return base.GetCleared();

Radzen.Blazor/DropDownBaseItemRenderEventArgs.cs

@@ -10,7 +10,7 @@ public class DropDownBaseItemRenderEventArgs<TValue>
     /// <summary>
     /// Gets the data item.
     /// </summary>
-    public object Item { get; internal set; }
+    public object? Item { get; internal set; }
 
     /// <summary>
     /// Gets or sets a value indicating whether this item is visible.

Radzen.Blazor/DropDownItemRenderEventArgs.cs

@@ -10,6 +10,6 @@ public class DropDownItemRenderEventArgs<TValue> : DropDownBaseItemRenderEventAr
     /// <summary>
     /// Gets the DropDown.
     /// </summary>
-    public RadzenDropDown<TValue> DropDown { get; internal set; }
+    public RadzenDropDown<TValue>? DropDown { get; internal set; }
 }
 

Radzen.Blazor/DynamicExtensions.cs

@@ -9,8 +9,13 @@ namespace System.Linq.Dynamic.Core
     /// </summary>
     public static class DynamicExtensions
     {
-        static readonly Func<string, Type> typeLocator = type => AppDomain.CurrentDomain.GetAssemblies()
-            .SelectMany(a => a.GetTypes()).FirstOrDefault(t => t.FullName.Replace("+", ".") == type);
+        static readonly Func<string, Type?> typeLocator = type => AppDomain.CurrentDomain.GetAssemblies()
+            .SelectMany(a => a.GetTypes())
+            .FirstOrDefault(t =>
+            {
+                var fullName = t.FullName;
+                return fullName != null && fullName.Replace("+", ".", StringComparison.Ordinal) == type;
+            });
 
         /// <summary>
         /// Filters using the specified filter descriptors.
@@ -18,28 +23,30 @@ namespace System.Linq.Dynamic.Core
         public static IQueryable<T> Where<T>(
             this IQueryable<T> source,
             string predicate,
-            object[] parameters = null, object[] otherParameters = null)
+            object[]? parameters = null, object[]? otherParameters = null)
         {
+            ArgumentNullException.ThrowIfNull(source);
+
             try
             {
                 if (parameters != null && !string.IsNullOrEmpty(predicate))
                 {
                     predicate = Regex.Replace(predicate, @"@(\d+)", match =>
                     {
-                        int index = int.Parse(match.Groups[1].Value);
+                        int index = int.Parse(match.Groups[1].Value, System.Globalization.CultureInfo.InvariantCulture);
                         if (index >= parameters.Length)
                             throw new InvalidOperationException($"No parameter provided for {match.Value}");
 
-                        return ExpressionSerializer.FormatValue(parameters[index]);
+                        return ExpressionSerializer.FormatValue(parameters[index]) ?? string.Empty;
                     });
                 }
 
-                predicate = (predicate == "true" ? "" : predicate)
-                    .Replace("DateTime(", "DateTime.Parse(")
-                    .Replace("DateTimeOffset(", "DateTimeOffset.Parse(")
-                    .Replace("DateOnly(", "DateOnly.Parse(")
-                    .Replace("Guid(", "Guid.Parse(")
-                    .Replace(" = ", " == ");
+                predicate = (predicate == "true" ? "" : predicate ?? string.Empty)
+                    .Replace("DateTime(", "DateTime.Parse(", StringComparison.Ordinal)
+                    .Replace("DateTimeOffset(", "DateTimeOffset.Parse(", StringComparison.Ordinal)
+                    .Replace("DateOnly(", "DateOnly.Parse(", StringComparison.Ordinal)
+                    .Replace("Guid(", "Guid.Parse(", StringComparison.Ordinal)
+                    .Replace(" = ", " == ", StringComparison.Ordinal);
 
                 return !string.IsNullOrEmpty(predicate) ?
                     source.Where(ExpressionParser.ParsePredicate<T>(predicate, typeLocator)) : source;
@@ -56,8 +63,10 @@ namespace System.Linq.Dynamic.Core
         public static IOrderedQueryable<T> OrderBy<T>(
             this IQueryable<T> source,
             string selector,
-            object[] parameters = null)
+            object[]? parameters = null)
         {
+            ArgumentNullException.ThrowIfNull(source);
+
             try
             {
                 return QueryableExtension.OrderBy(source, selector);
@@ -71,8 +80,10 @@ namespace System.Linq.Dynamic.Core
         /// <summary>
         /// Projects each element of a sequence into a collection of property values.
         /// </summary>
-        public static IQueryable Select<T>(this IQueryable<T> source, string selector, object[] parameters = null)
+        public static IQueryable Select<T>(this IQueryable<T> source, string selector, object[]? parameters = null)
         {
+            ArgumentNullException.ThrowIfNull(source);
+
             if (source.ElementType == typeof(object))
             {
                 var elementType = source.ElementType;
@@ -95,8 +106,10 @@ namespace System.Linq.Dynamic.Core
         /// <summary>
         /// Projects each element of a sequence into a collection of property values.
         /// </summary>
-        public static IQueryable Select(this IQueryable source, string selector, object[] parameters = null)
+        public static IQueryable Select(this IQueryable source, string selector, object[]? parameters = null)
         {
+            ArgumentNullException.ThrowIfNull(source);
+            ArgumentNullException.ThrowIfNull(selector);
             return source.Select(selector, expression => ExpressionParser.ParseLambda(expression, source.ElementType));
         }
 
@@ -109,18 +122,27 @@ namespace System.Linq.Dynamic.Core
                     return source;
                 }
 
-                if (!selector.Contains("=>"))
+                if (!selector.Contains("=>", StringComparison.Ordinal))
                 {
                     var properties = selector
-                        .Replace("new (", "").Replace(")", "").Replace("new {", "").Replace("}", "").Trim()
+                        .Replace("new (", "", StringComparison.Ordinal).Replace(")", "", StringComparison.Ordinal).Replace("new {", "", StringComparison.Ordinal).Replace("}", "", StringComparison.Ordinal).Trim()
                         .Split(",", StringSplitOptions.RemoveEmptyEntries);
 
                     selector = string.Join(", ", properties
-                        .Select(s => (s.Contains(" as ") ? s.Split(" as ").LastOrDefault().Trim().Replace(".", "_") : s.Trim().Replace(".", "_")) +
-                            " = " + $"it.{s.Split(" as ").FirstOrDefault().Replace(".", "?.").Trim()}"));
+                        .Select(s =>
+                        {
+                            var parts = s.Split(" as ", StringSplitOptions.RemoveEmptyEntries);
+                            var sourcePart = (parts.FirstOrDefault() ?? s).Trim();
+                            var targetPart = (parts.Length > 1 ? parts.Last() : sourcePart).Trim();
+
+                            var safeTarget = targetPart.Replace(".", "_", StringComparison.Ordinal);
+                            var safeSource = sourcePart.Replace(".", "?.", StringComparison.Ordinal);
+
+                            return $"{safeTarget} = it.{safeSource}";
+                        }));
                 }
 
-                var lambda = lambdaCreator(selector.Contains("=>") ? selector : $"it => new {{ {selector} }}");
+                var lambda = lambdaCreator(selector.Contains("=>", StringComparison.Ordinal) ? selector : $"it => new {{ {selector} }}");
 
                 return source.Provider.CreateQuery(Expression.Call(typeof(Queryable), nameof(Queryable.Select),
                           [source.ElementType, lambda.Body.Type], source.Expression, Expression.Quote(lambda)));

Radzen.Blazor/DynamicTypeFactory.cs

@@ -39,7 +39,7 @@ static class DynamicTypeFactory
                       "set_" + propertyNames[i],
                       MethodAttributes.Public | MethodAttributes.SpecialName | MethodAttributes.HideBySig,
                       null,
-                      [propertyTypes[i]]);
+                      new[] { propertyTypes[i] });
 
             var setterIl = setterMethod.GetILGenerator();
             setterIl.Emit(OpCodes.Ldarg_0);
@@ -51,6 +51,10 @@ static class DynamicTypeFactory
         }
 
         var dynamicType = typeBuilder.CreateType();
+        if (dynamicType == null)
+        {
+            throw new InvalidOperationException("Failed to create dynamic type.");
+        }
         return dynamicType;
     }
 }

Radzen.Blazor/ExpressionParser.cs

@@ -28,7 +28,7 @@ public class ExpressionParser
     /// </summary>
     public static Expression<Func<T, TResult>> ParseLambda<T, TResult>(string expression, Func<string, Type?>? typeResolver = null)
     {
-        var lambda = ParseLambda(expression, typeof(T), typeResolver);
+        var lambda = ParseLambda<T>(expression, typeResolver);
 
         return Expression.Lambda<Func<T, TResult>>(lambda.Body, lambda.Parameters[0]);
     }
@@ -52,7 +52,7 @@ public class ExpressionParser
     }
 
     private readonly List<Token> tokens;
-    private int position = 0;
+    private int position;
     private readonly Func<string, Type?>? typeResolver;
     private readonly Stack<ParameterExpression> parameterStack = new();
 

Radzen.Blazor/ExpressionSerializer.cs

@@ -30,6 +30,7 @@ public class ExpressionSerializer : ExpressionVisitor
     /// <inheritdoc/>
     protected override Expression VisitLambda<T>(Expression<T> node)
     {
+        ArgumentNullException.ThrowIfNull(node);
         if (node.Parameters.Count > 1)
         {
             _sb.Append("(");
@@ -52,6 +53,7 @@ public class ExpressionSerializer : ExpressionVisitor
     /// <inheritdoc/>
     protected override Expression VisitParameter(ParameterExpression node)
     {
+        ArgumentNullException.ThrowIfNull(node);
         _sb.Append(node.Name);
         return node;
     }
@@ -59,10 +61,11 @@ public class ExpressionSerializer : ExpressionVisitor
     /// <inheritdoc/>
     protected override Expression VisitMember(MemberExpression node)
     {
+        ArgumentNullException.ThrowIfNull(node);
         if (node.Expression != null)
         {
             Visit(node.Expression);
-            _sb.Append($".{node.Member.Name}");
+            _sb.Append(CultureInfo.InvariantCulture, $".{node.Member.Name}");
         }
         else
         {
@@ -74,14 +77,15 @@ public class ExpressionSerializer : ExpressionVisitor
     /// <inheritdoc/>
     protected override Expression VisitMethodCall(MethodCallExpression node)
     {
+        ArgumentNullException.ThrowIfNull(node);
         if (node.Method.IsStatic && node.Arguments.Count > 0 &&
-            (node.Method.DeclaringType == typeof(Enumerable) || 
+            (node.Method.DeclaringType == typeof(Enumerable) ||
                 node.Method.DeclaringType == typeof(Queryable)))
         {
             Visit(node.Arguments[0]);
-            _sb.Append($".{node.Method.Name}(");
+            _sb.Append(CultureInfo.InvariantCulture, $".{node.Method.Name}(");
 
-            for (int i = 1; i < node.Arguments.Count; i++) 
+            for (int i = 1; i < node.Arguments.Count; i++)
             {
                 if (i > 1) _sb.Append(", ");
 
@@ -99,7 +103,7 @@ public class ExpressionSerializer : ExpressionVisitor
         }
         else if (node.Method.IsStatic)
         {
-            _sb.Append($"{node.Method.DeclaringType.Name}.{node.Method.Name}(");
+            _sb.Append(CultureInfo.InvariantCulture, $"{node.Method.DeclaringType?.Name}.{node.Method.Name}(");
 
             for (int i = 0; i < node.Arguments.Count; i++)
             {
@@ -114,11 +118,11 @@ public class ExpressionSerializer : ExpressionVisitor
             if (node.Object != null)
             {
                 Visit(node.Object);
-                _sb.Append($".{node.Method.Name}(");
+                _sb.Append(CultureInfo.InvariantCulture, $".{node.Method.Name}(");
             }
             else
             {
-                _sb.Append($"{node.Method.Name}(");
+                _sb.Append(CultureInfo.InvariantCulture, $"{node.Method.Name}(");
             }
 
             for (int i = 0; i < node.Arguments.Count; i++)
@@ -136,17 +140,18 @@ public class ExpressionSerializer : ExpressionVisitor
     /// <inheritdoc/>
     protected override Expression VisitUnary(UnaryExpression node)
     {
+        ArgumentNullException.ThrowIfNull(node);
         if (node.NodeType == ExpressionType.Not)
         {
             _sb.Append("(!(");
             Visit(node.Operand);
             _sb.Append("))");
         }
-        else if (node.NodeType == ExpressionType.Convert) 
+        else if (node.NodeType == ExpressionType.Convert)
         {
             if (node.Operand is IndexExpression indexExpr)
             {
-                _sb.Append($"({node.Type.DisplayName(true).Replace("+",".")})");
+                _sb.Append(CultureInfo.InvariantCulture, $"({node.Type.DisplayName(true).Replace("+", ".", StringComparison.Ordinal)})");
 
                 Visit(indexExpr.Object);
 
@@ -175,20 +180,18 @@ public class ExpressionSerializer : ExpressionVisitor
     /// <inheritdoc/>
     protected override Expression VisitConstant(ConstantExpression node)
     {
+        ArgumentNullException.ThrowIfNull(node);
         _sb.Append(FormatValue(node.Value));
         return node;
     }
 
-    internal static string FormatValue(object value)
+    internal static string? FormatValue(object? value)
     {
-        if (value == null)
-            return "null";
-
         return value switch
         {
-            string s when s == string.Empty => @"""""",
+            string s when s.Length == 0 => @"""""",
             null => "null",
-            string s => @$"""{s.Replace("\"", "\\\"")}""",
+            string s => @$"""{s.Replace("\"", "\\\"", StringComparison.Ordinal)}""",
             char c => $"'{c}'",
             bool b => b.ToString().ToLowerInvariant(),
             DateTime dt => FormatDateTime(dt),
@@ -198,7 +201,7 @@ public class ExpressionSerializer : ExpressionVisitor
             Guid guid => $"Guid.Parse(\"{guid.ToString("D", CultureInfo.InvariantCulture)}\")",
             IEnumerable enumerable when value is not string => FormatEnumerable(enumerable),
             _ => value.GetType().IsEnum
-                ? $"({value.GetType().FullName.Replace("+", ".")})" + Convert.ChangeType(value, Enum.GetUnderlyingType(value.GetType()), CultureInfo.InvariantCulture).ToString()
+                ? $"({value.GetType()?.FullName?.Replace("+", ".", StringComparison.Ordinal)})" + Convert.ChangeType(value, Enum.GetUnderlyingType(value.GetType()), CultureInfo.InvariantCulture).ToString()
                 : Convert.ToString(value, CultureInfo.InvariantCulture)
         };
     }
@@ -214,14 +217,15 @@ public class ExpressionSerializer : ExpressionVisitor
     private static string FormatEnumerable(IEnumerable enumerable)
     {
         var arrayType = enumerable.AsQueryable().ElementType;
-        
+
         var items = enumerable.Cast<object>().Select(FormatValue);
-        return $"new {(Nullable.GetUnderlyingType(arrayType) != null ? arrayType.DisplayName(true).Replace("+", ".") : "")}[] {{ {string.Join(", ", items)} }}";
+        return $"new {(Nullable.GetUnderlyingType(arrayType) != null ? arrayType.DisplayName(true).Replace("+", ".", StringComparison.Ordinal) : "")}[] {{ {string.Join(", ", items)} }}";
     }
 
     /// <inheritdoc/>
     protected override Expression VisitNewArray(NewArrayExpression node)
     {
+        ArgumentNullException.ThrowIfNull(node);
         bool needsParentheses = node.NodeType == ExpressionType.NewArrayInit &&
                                 (node.Expressions.Count > 1 || node.Expressions[0].NodeType != ExpressionType.Constant);
 
@@ -245,9 +249,10 @@ public class ExpressionSerializer : ExpressionVisitor
     /// <inheritdoc/>
     protected override Expression VisitBinary(BinaryExpression node)
     {
+        ArgumentNullException.ThrowIfNull(node);
         _sb.Append("(");
         Visit(node.Left);
-        _sb.Append($" {GetOperator(node.NodeType)} ");
+        _sb.Append(CultureInfo.InvariantCulture, $" {GetOperator(node.NodeType)} ");
         Visit(node.Right);
         _sb.Append(")");
         return node;
@@ -256,6 +261,7 @@ public class ExpressionSerializer : ExpressionVisitor
     /// <inheritdoc/>
     protected override Expression VisitConditional(ConditionalExpression node)
     {
+        ArgumentNullException.ThrowIfNull(node);
         _sb.Append("(");
         Visit(node.Test);
         _sb.Append(" ? ");
@@ -290,7 +296,7 @@ public class ExpressionSerializer : ExpressionVisitor
             ExpressionType.Coalesce => "??",
             _ => throw new NotSupportedException($"Unsupported operator: {type}")
         };
-    }  
+    }
 }
 
 /// <summary>
@@ -333,6 +339,7 @@ public static class SharedTypeExtensions
     /// <returns>A string representing the type name.</returns>
     public static string DisplayName(this Type type, bool fullName = true, bool compilable = false)
     {
+        ArgumentNullException.ThrowIfNull(type);
         var stringBuilder = new StringBuilder();
         ProcessType(stringBuilder, type, fullName, compilable);
         return stringBuilder.ToString();
@@ -443,7 +450,7 @@ public static class SharedTypeExtensions
             }
         }
 
-        var genericPartIndex = type.Name.IndexOf('`');
+        var genericPartIndex = type.Name.IndexOf('`', StringComparison.Ordinal);
         if (genericPartIndex <= 0)
         {
             builder.Append(type.Name);

Radzen.Blazor/Extensions.cs

@@ -2,6 +2,7 @@
 using System.Collections;
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
+using System.Globalization;
 using System.Linq;
 using System.Reflection;
 using System.Reflection.Emit;
@@ -18,8 +19,9 @@ namespace Radzen.Blazor
         /// <summary>
         /// Gets enum description.
         /// </summary>
-        public static string GetDisplayDescription(this Enum enumValue, Func<string, string> translationFunction = null)
+        public static string GetDisplayDescription(this Enum enumValue, Func<string, string>? translationFunction = null)
         {
+            ArgumentNullException.ThrowIfNull(enumValue);
             var enumValueAsString = enumValue.ToString();
             var val = enumValue.GetType().GetMember(enumValueAsString).FirstOrDefault();
             var enumVal = val?.GetCustomAttribute<DisplayAttribute>()?.GetDescription() ?? enumValueAsString;
@@ -33,10 +35,12 @@ namespace Radzen.Blazor
         /// <summary>
         /// Converts Enum to IEnumerable of Value/Text.
         /// </summary>
-        public static IEnumerable<object> EnumAsKeyValuePair(Type enumType, Func<string, string> translationFunction = null)
+        public static IEnumerable<object> EnumAsKeyValuePair(Type enumType, Func<string, string>? translationFunction = null)
         {
+            ArgumentNullException.ThrowIfNull(enumType);
+
             Type underlyingType = Enum.GetUnderlyingType(enumType);
-            return Enum.GetValues(enumType).Cast<Enum>().Distinct().Select(val => new { Value = Convert.ChangeType(val, underlyingType), Text = val.GetDisplayDescription(translationFunction) });
+            return Enum.GetValues(enumType).Cast<Enum>().Distinct().Select(val => new { Value = Convert.ChangeType(val, underlyingType, CultureInfo.InvariantCulture), Text = val.GetDisplayDescription(translationFunction) });
         }
 
         /// <summary>
@@ -67,7 +71,7 @@ namespace Radzen.Blazor
             var value = typeValue.ToString();
             value = Regex.Replace(value, "([^A-Z])([A-Z])", "$1-$2");
             return Regex.Replace(value, "([A-Z]+)([A-Z][^A-Z$])", "$1-$2")
-                .Trim().ToLower();
+                .Trim().ToLowerInvariant();
         }
     }
 }

Radzen.Blazor/FileInfo.cs

@@ -17,7 +17,7 @@ public class FileInfo : IBrowserFile
         //
     }
 
-    private IBrowserFile source;
+    private IBrowserFile? source;
 
     /// <summary>
     /// Creates FileInfo with IBrowserFile as source.
@@ -28,7 +28,9 @@ public class FileInfo : IBrowserFile
         this.source = source;
     }
 
-    private string name;
+    private string? name;
+    private DateTimeOffset? lastModified;
+    private string? contentType;
 
     /// <summary>
     /// Gets the name of the selected file.
@@ -37,7 +39,7 @@ public class FileInfo : IBrowserFile
     {
         get
         {
-            return name ?? source.Name;
+                return name ?? source?.Name ?? string.Empty;
         }
         set
         {
@@ -65,17 +67,25 @@ public class FileInfo : IBrowserFile
     /// <summary>
     /// Gets the IBrowserFile source.
     /// </summary>
-    public IBrowserFile Source => source;
+    public IBrowserFile? Source => source;
 
     /// <summary>
     /// Gets the LastModified.
     /// </summary>
-    public DateTimeOffset LastModified => source.LastModified;
+    public DateTimeOffset LastModified
+    {
+        get => lastModified ?? source?.LastModified ?? default;
+        set => lastModified = value;
+    }
 
     /// <summary>
     /// Gets the ContentType.
     /// </summary>
-    public string ContentType => source.ContentType;
+    public string ContentType
+    {
+        get => contentType ?? source?.ContentType ?? string.Empty;
+        set => contentType = value;
+    }
 
     /// <summary>
     /// Open read stream.
@@ -85,6 +95,11 @@ public class FileInfo : IBrowserFile
     /// <returns>The stream.</returns>
     public System.IO.Stream OpenReadStream(long maxAllowedSize = 512000, CancellationToken cancellationToken = default)
     {
+        if (source == null)
+        {
+            throw new InvalidOperationException("No underlying browser file is associated with this FileInfo instance.");
+        }
+
         return source.OpenReadStream(maxAllowedSize, cancellationToken);
     }
 }

Radzen.Blazor/FilterDescriptor.cs

@@ -12,26 +12,26 @@ public class FilterDescriptor
     /// Gets or sets the name of the filtered property.
     /// </summary>
     /// <value>The property.</value>
-    public string Property { get; set; }
+    public string? Property { get; set; }
 
     /// <summary>
     /// Gets or sets the property type.
     /// </summary>
     /// <value>The property type.</value>
     [JsonIgnore]
-    public Type Type { get; set; }
+    public Type? Type { get; set; }
 
     /// <summary>
     /// Gets or sets the name of the filtered property.
     /// </summary>
     /// <value>The property.</value>
-    public string FilterProperty { get; set; }
+    public string? FilterProperty { get; set; }
 
     /// <summary>
     /// Gets or sets the value to filter by.
     /// </summary>
     /// <value>The filter value.</value>
-    public object FilterValue { get; set; }
+    public object? FilterValue { get; set; }
 
     /// <summary>
     /// Gets or sets the operator which will compare the property value with <see cref="FilterValue" />.
@@ -43,7 +43,7 @@ public class FilterDescriptor
     /// Gets or sets a second value to filter by.
     /// </summary>
     /// <value>The second filter value.</value>
-    public object SecondFilterValue { get; set; }
+    public object? SecondFilterValue { get; set; }
 
     /// <summary>
     /// Gets or sets the operator which will compare the property value with <see cref="SecondFilterValue" />.

Radzen.Blazor/FormComponent.cs

@@ -39,8 +39,30 @@ namespace Radzen
         /// AutoCompleteType.</value>
         public virtual string AutoCompleteAttribute
         {
-            get => Attributes != null && Attributes.ContainsKey("AutoComplete") && $"{Attributes["AutoComplete"]}".ToLower() == "false" ? DefaultAutoCompleteAttribute :
-                Attributes != null && Attributes.ContainsKey("AutoComplete") ? Attributes["AutoComplete"] as string ?? AutoCompleteType.GetAutoCompleteValue() : AutoCompleteType.GetAutoCompleteValue();
+            get
+            {
+                if (Attributes != null && Attributes.TryGetValue("AutoComplete", out var value))
+                {
+                    var v = (object?)value;
+                    var autoCompleteValue = v switch
+                    {
+                        bool boolValue => boolValue
+                            ? AutoCompleteType.GetAutoCompleteValue()
+                            : DefaultAutoCompleteAttribute,
+                        string stringValue when bool.TryParse(stringValue, out var boolValue) => boolValue
+                            ? AutoCompleteType.GetAutoCompleteValue()
+                            : DefaultAutoCompleteAttribute,
+                        AutoCompleteType typeValue => typeValue.GetAutoCompleteValue(),
+                        _ => value != null ? value.ToString() ?? AutoCompleteType.GetAutoCompleteValue() : AutoCompleteType.GetAutoCompleteValue()
+                    };
+
+                    return string.Equals(autoCompleteValue, "false", StringComparison.OrdinalIgnoreCase)
+                        ? DefaultAutoCompleteAttribute
+                        : autoCompleteValue;
+                }
+
+                return AutoCompleteType.GetAutoCompleteValue();
+            }
         }
 
         /// <summary>
@@ -48,7 +70,7 @@ namespace Radzen
         /// </summary>
         public virtual string DefaultAutoCompleteAttribute { get; set; } = "off";
 
-        object ariaAutoComplete;
+        object? ariaAutoComplete;
 
         /// <inheritdoc />
         public override async Task SetParametersAsync(ParameterView parameters)
@@ -56,10 +78,10 @@ namespace Radzen
             parameters = parameters.TryGetValue("aria-autocomplete", out ariaAutoComplete) ?
                 ParameterView.FromDictionary(parameters
                     .ToDictionary().Where(i => i.Key != "aria-autocomplete").ToDictionary(i => i.Key, i => i.Value)
-                    .ToDictionary(i => i.Key, i => i.Value))
+                    .ToDictionary(i => i.Key, i => (object?)i.Value))
                 : parameters;
 
-            await base.SetParametersAsync(parameters);
+            await base.SetParametersAsync(parameters).ConfigureAwait(false);
         }
 
         /// <summary>
@@ -70,9 +92,11 @@ namespace Radzen
         /// <summary>
         /// Gets the aria-autocomplete attribute's string value.
         /// </summary>
-        public virtual string AriaAutoCompleteAttribute
+        public virtual string? AriaAutoCompleteAttribute
         {
-            get => AutoCompleteAttribute == DefaultAutoCompleteAttribute ? DefaultAriaAutoCompleteAttribute : ariaAutoComplete as string;
+            get => string.Equals(AutoCompleteAttribute, DefaultAutoCompleteAttribute, StringComparison.Ordinal)
+                ? DefaultAriaAutoCompleteAttribute
+                : ariaAutoComplete as string;
         }
 
     }
@@ -96,7 +120,7 @@ namespace Radzen
         /// </summary>
         /// <value>The component name.</value>
         [Parameter]
-        public string Name { get; set; }
+        public string? Name { get; set; }
 
         /// <summary>
         /// Gets or sets the tab order index for keyboard navigation.
@@ -112,7 +136,7 @@ namespace Radzen
         /// </summary>
         /// <value>The placeholder.</value>
         [Parameter]
-        public string Placeholder { get; set; }
+        public string? Placeholder { get; set; }
 
         /// <summary>
         /// Gets or sets a value indicating whether this <see cref="FormComponent{T}"/> is disabled.
@@ -124,21 +148,21 @@ namespace Radzen
         /// <summary>
         /// The form
         /// </summary>
-        IRadzenForm _form;
+        IRadzenForm? _form;
 
         /// <summary>
         /// Gets or sets the edit context.
         /// </summary>
         /// <value>The edit context.</value>
         [CascadingParameter]
-        public EditContext EditContext { get; set; }
+        public EditContext? EditContext { get; set; }
 
         /// <summary>
         /// Gets or sets the form.
         /// </summary>
         /// <value>The form.</value>
         [CascadingParameter]
-        public IRadzenForm Form
+        public IRadzenForm? Form
         {
             get
             {
@@ -189,14 +213,14 @@ namespace Radzen
         /// <summary>
         /// The value
         /// </summary>
-        protected T _value;
+        protected T? _value;
 
         /// <summary>
         /// Gets or sets the value.
         /// </summary>
         /// <value>The value.</value>
         [Parameter]
-        public virtual T Value
+        public virtual T? Value
         {
             get
             {
@@ -230,7 +254,7 @@ namespace Radzen
         /// </summary>
         /// <value>The value expression.</value>
         [Parameter]
-        public Expression<Func<T>> ValueExpression { get; set; }
+        public Expression<Func<T>>? ValueExpression { get; set; }
         /// <summary>
         /// Sets the parameters asynchronous.
         /// </summary>
@@ -262,7 +286,7 @@ namespace Radzen
         /// </summary>
         /// <param name="sender">The sender.</param>
         /// <param name="e">The <see cref="ValidationStateChangedEventArgs"/> instance containing the event data.</param>
-        private void ValidationStateChanged(object sender, ValidationStateChangedEventArgs e)
+        private void ValidationStateChanged(object? sender, ValidationStateChangedEventArgs e)
         {
             StateHasChanged();
         }
@@ -280,19 +304,21 @@ namespace Radzen
             }
 
             Form?.RemoveComponent(this);
+
+            GC.SuppressFinalize(this);
         }
 
         /// <summary>
         /// Gets the value.
         /// </summary>
         /// <returns>System.Object.</returns>
-        public object GetValue()
+        public object? GetValue()
         {
             return Value;
         }
 
         /// <summary>
-        /// Handles the <see cref="E:ContextMenu" /> event.
+        /// Handles the ContextMenu event.
         /// </summary>
         /// <param name="args">The <see cref="MouseEventArgs"/> instance containing the event data.</param>
         /// <returns>Task.</returns>
@@ -318,10 +344,10 @@ namespace Radzen
 
         /// <summary> Provides support for RadzenFormField integration. </summary>
         [CascadingParameter]
-        public IFormFieldContext FormFieldContext { get; set; }
+        public IFormFieldContext? FormFieldContext { get; set; }
 
         /// <summary> Gets the current placeholder. Returns empty string if this component is inside a RadzenFormField.</summary>
-        protected string CurrentPlaceholder => FormFieldContext?.AllowFloatingLabel == true ? " " : Placeholder;
+        protected string? CurrentPlaceholder => FormFieldContext?.AllowFloatingLabel == true ? " " : Placeholder;
 
         /// <inheritdoc/>
         public virtual async ValueTask FocusAsync()

Radzen.Blazor/FormInvalidSubmitEventArgs.cs

@@ -10,6 +10,6 @@ public class FormInvalidSubmitEventArgs
     /// <summary>
     /// Gets the validation errors.
     /// </summary>
-    public IEnumerable<string> Errors { get; set; }
+    public IEnumerable<string>? Errors { get; set; }
 }
 

Radzen.Blazor/GaugeBase.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Globalization;
 using System.Threading.Tasks;
 using Microsoft.AspNetCore.Components;
 using Microsoft.JSInterop;
@@ -18,7 +19,7 @@ namespace Radzen.Blazor
         /// </summary>
         /// <value>The child content.</value>
         [Parameter]
-        public RenderFragment ChildContent
+        public RenderFragment? ChildContent
         {
             get; set;
         }
@@ -38,7 +39,7 @@ namespace Radzen.Blazor
         /// <summary>
         /// The width and height are set
         /// </summary>
-        bool widthAndHeightAreSet = false;
+        bool widthAndHeightAreSet;
         /// <summary>
         /// The first render
         /// </summary>
@@ -57,7 +58,7 @@ namespace Radzen.Blazor
             {
                 visibleChanged = false;
 
-                if (Visible)
+                if (Visible && JSRuntime != null)
                 {
                     var rect = await JSRuntime.InvokeAsync<Rect>("Radzen.createGauge", Element, Reference);
 
@@ -117,23 +118,20 @@ namespace Radzen.Blazor
             double width = 0;
             double height = 0;
 
-            if (CurrentStyle.ContainsKey("height"))
+            if (CurrentStyle.TryGetValue("height", out var pixelHeight))
             {
-                var pixelHeight = CurrentStyle["height"];
-
-                if (pixelHeight.EndsWith("px"))
+                if (pixelHeight.EndsWith("px", StringComparison.Ordinal))
                 {
-                    height = Convert.ToDouble(pixelHeight.TrimEnd("px".ToCharArray()));
+                    height = Convert.ToDouble(pixelHeight.TrimEnd("px".ToCharArray()), CultureInfo.InvariantCulture);
                 }
             }
 
-            if (CurrentStyle.ContainsKey("width"))
+            if (CurrentStyle.TryGetValue("width", out var pixelWidth))
             {
-                var pixelWidth = CurrentStyle["width"];
 
-                if (pixelWidth.EndsWith("px"))
+                if (pixelWidth.EndsWith("px", StringComparison.Ordinal))
                 {
-                    width = Convert.ToDouble(pixelWidth.TrimEnd("px".ToCharArray()));
+                    width = Convert.ToDouble(pixelWidth.TrimEnd("px".ToCharArray()), CultureInfo.InvariantCulture);
                 }
             }
 
@@ -149,7 +147,7 @@ namespace Radzen.Blazor
         /// <summary>
         /// The visible changed
         /// </summary>
-        private bool visibleChanged = false;
+        private bool visibleChanged;
 
         /// <summary>
         /// Set parameters as an asynchronous operation.
@@ -166,7 +164,7 @@ namespace Radzen.Blazor
 
             if (visibleChanged && !firstRender)
             {
-                if (Visible == false)
+                if (Visible == false && JSRuntime != null)
                 {
                     await JSRuntime.InvokeVoidAsync("Radzen.destroyGauge", Element);
                 }
@@ -185,10 +183,12 @@ namespace Radzen.Blazor
         {
             base.Dispose();
 
-            if (Visible)
+            if (Visible && JSRuntime != null)
             {
                 JSRuntime.InvokeVoid("Radzen.destroyGauge", Element);
             }
+
+            GC.SuppressFinalize(this);
         }
 
         /// <summary>

Radzen.Blazor/GoogleMapClickEventArgs.cs

@@ -8,6 +8,6 @@ public class GoogleMapClickEventArgs
     /// <summary>
     /// The position which represents the clicked map location.
     /// </summary>
-    public GoogleMapPosition Position { get; set; }
+    public GoogleMapPosition? Position { get; set; }
 }
 

Radzen.Blazor/GoogleMapPosition.cs

@@ -20,7 +20,7 @@ public class GoogleMapPosition : IEquatable<GoogleMapPosition>
     public double Lng { get; set; }
 
     /// <inheritdoc />
-    public bool Equals(GoogleMapPosition other)
+    public bool Equals(GoogleMapPosition? other)
     {
         if (other != null)
         {
@@ -31,7 +31,7 @@ public class GoogleMapPosition : IEquatable<GoogleMapPosition>
     }
 
     /// <inheritdoc />
-    public override bool Equals(object obj)
+    public override bool Equals(object? obj)
     {
         return this.Equals(obj as GoogleMapPosition);
     }

Radzen.Blazor/Group.cs

@@ -9,13 +9,13 @@ public class Group
     /// Gets or sets the data.
     /// </summary>
     /// <value>The data.</value>
-    public GroupResult Data { get; set; }
+    public GroupResult Data { get; set; } = new GroupResult();
 
     /// <summary>
     /// Gets or sets the group descriptor.
     /// </summary>
     /// <value>The group descriptor.</value>
-    public GroupDescriptor GroupDescriptor { get; set; }
+    public GroupDescriptor? GroupDescriptor { get; set; }
 
     /// <summary>
     /// Gets or sets the level.

Radzen.Blazor/GroupDescriptor.cs

@@ -9,7 +9,7 @@ public class GroupDescriptor
     /// Gets or sets the property to group by.
     /// </summary>
     /// <value>The property.</value>
-    public string Property { get; set; }
+    public string Property { get; set; } = string.Empty;
 
     /// <summary>
     /// Gets or sets the sort order.
@@ -21,13 +21,13 @@ public class GroupDescriptor
     /// Gets or sets the title displayed in the group.
     /// </summary>
     /// <value>The title.</value>
-    public string Title { get; set; }
+    public string Title { get; set; } = string.Empty;
 
     /// <summary>
     /// Gets or sets the format string used to display the key in the group.
     /// </summary>
     /// <value>The format string.</value>
-    public string FormatString { get; set; }
+    public string FormatString { get; set; } = string.Empty;
 
     /// <summary>
     /// Gets or sets a value indicating whether to show the footer for the group.

Radzen.Blazor/GroupResult.cs

@@ -22,12 +22,12 @@ public class GroupResult
     /// <summary>
     /// The resulting elements in the group.
     /// </summary>
-    public IEnumerable Items { get; internal set; }
+    public IEnumerable? Items { get; internal set; }
 
     /// <summary>
     /// The resulting subgroups in the group.
     /// </summary>
-    public IEnumerable<GroupResult> Subgroups { get; internal set; }
+    public IEnumerable<GroupResult>? Subgroups { get; internal set; }
 
     /// <summary>
     /// Returns a <see cref="System.String" /> showing the key of the group and the number of items in the group.

Radzen.Blazor/GroupRowRenderEventArgs.cs

@@ -15,7 +15,7 @@ public class GroupRowRenderEventArgs
     /// <summary>
     /// Gets the data item which the current row represents.
     /// </summary>
-    public Group Group { get; internal set; }
+    public Group? Group { get; internal set; }
 
     /// <summary>
     /// Gets or sets a value indicating whether this group row is expanded.

Radzen.Blazor/HtmlEditorExecuteEventArgs.cs

@@ -24,6 +24,6 @@ public class HtmlEditorExecuteEventArgs
     /// <summary>
     /// Gets the name of the command which RadzenHtmlEditor is executing.
     /// </summary>
-    public string CommandName { get; set; }
+    public string? CommandName { get; set; }
 }
 

Radzen.Blazor/HtmlEditorPasteEventArgs.cs

@@ -9,6 +9,6 @@ public class HtmlEditorPasteEventArgs
     /// Gets or sets the HTML content that is pasted in RadzenHtmlEditor. Use the setter to filter unwanted markup from the pasted value.
     /// </summary>
     /// <value>The HTML.</value>
-    public string Html { get; set; }
+    public string? Html { get; set; }
 }
 

Radzen.Blazor/HttpResponseMessageExtensions.cs

@@ -22,8 +22,9 @@ namespace Radzen
         /// <exception cref="Exception"></exception>
         /// <exception cref="Exception">Unable to parse the response.</exception>
         /// <exception cref="Exception"></exception>
-        public static async Task<T> ReadAsync<T>(this HttpResponseMessage response)
+        public static async Task<T?> ReadAsync<T>(this HttpResponseMessage response)
         {
+            ArgumentNullException.ThrowIfNull(response);
             try
             {
                 response.EnsureSuccessStatusCode();
@@ -42,7 +43,8 @@ namespace Radzen
                 var responseAsString = await response.Content.ReadAsStringAsync();
                 if (!string.IsNullOrEmpty(responseAsString))
                 {
-                    if (response.Content.Headers.ContentType.MediaType == "application/json")
+                    var mediaType = response.Content.Headers.ContentType?.MediaType;
+                    if (string.Equals(mediaType, "application/json", StringComparison.OrdinalIgnoreCase))
                     {
                         JsonDocument json;
                         try
@@ -51,7 +53,7 @@ namespace Radzen
                         }
                         catch
                         {
-                            throw new Exception("Unable to parse the response.");
+                            throw new InvalidOperationException("Unable to parse the response.");
                         }
 
                         JsonElement error;
@@ -60,13 +62,14 @@ namespace Radzen
                             JsonElement message;
                             if (error.TryGetProperty("message", out message))
                             {
-                                throw new Exception(message.GetString());
+                                var messageText = message.GetString();
+                                throw new InvalidOperationException(messageText ?? "An error occurred.");
                             }
                         }
                     }
                     else
                     {
-                        XElement error = null;
+                        XElement? error = null;
                         try
                         {
                             var xml = XDocument.Parse(responseAsString);
@@ -82,12 +85,12 @@ namespace Radzen
                         }
                         catch
                         {
-                            throw new Exception("Unable to parse the response.");
+                            throw new InvalidOperationException("Unable to parse the response.");
                         }
 
                         if (error != null)
                         {
-                            throw new Exception(error.Value);
+                            throw new InvalidOperationException(error.Value);
                         }
                     }
                 }

Radzen.Blazor/IAIChatService.cs

@@ -23,14 +23,14 @@ public interface IAIChatService
     /// <param name="apiKey">Optional API key to override the configured API key.</param>
     /// <param name="apiKeyHeader">Optional API key header name to override the configured header.</param>
     /// <returns>An async enumerable that yields streaming response chunks from the AI model.</returns>
-    IAsyncEnumerable<string> GetCompletionsAsync(string userInput, string sessionId = null, CancellationToken cancellationToken = default, string model = null, string systemPrompt = null, double? temperature = null, int? maxTokens = null, string endpoint = null, string proxy = null, string apiKey = null, string apiKeyHeader = null);
+    IAsyncEnumerable<string> GetCompletionsAsync(string userInput, string? sessionId = null, CancellationToken cancellationToken = default, string? model = null, string? systemPrompt = null, double? temperature = null, int? maxTokens = null, string? endpoint = null, string? proxy = null, string? apiKey = null, string? apiKeyHeader = null);
 
     /// <summary>
     /// Gets or creates a conversation session.
     /// </summary>
     /// <param name="sessionId">The session ID. If null, a new session will be created.</param>
     /// <returns>The conversation session.</returns>
-    ConversationSession GetOrCreateSession(string sessionId = null);
+    ConversationSession GetOrCreateSession(string? sessionId = null);
 
     /// <summary>
     /// Clears the conversation history for a specific session.

Radzen.Blazor/IRadzenFormComponent.cs

@@ -25,13 +25,13 @@ public interface IRadzenFormComponent
     /// Gets the value of the component.
     /// </summary>
     /// <returns>the value of the component - for example the text of RadzenTextBox.</returns>
-    object GetValue();
+    object? GetValue();
 
     /// <summary>
     /// Gets or sets the name of the component.
     /// </summary>
     /// <value>The name.</value>
-    string Name { get; set; }
+    string? Name { get; set; }
 
     /// <summary>
     /// Gets the field identifier.
@@ -58,6 +58,6 @@ public interface IRadzenFormComponent
     /// <summary>
     /// Sets the FormFieldContext of the component
     /// </summary>
-    IFormFieldContext FormFieldContext { get; }
+    IFormFieldContext? FormFieldContext { get; }
 }
 

Radzen.Blazor/LegendClickEventArgs.cs

@@ -10,13 +10,13 @@ public class LegendClickEventArgs
     /// <summary>
     /// Gets the data at the clicked location.
     /// </summary>
-    public object Data { get; set; }
+    public object? Data { get; set; }
 
     /// <summary>
     /// Gets the title of the clicked series. Determined by <see cref="CartesianSeries{TItem}.Title" />.
     /// </summary>
     /// <value>The title.</value>
-    public string Title { get; set; }
+    public string? Title { get; set; }
 
     /// <summary>
     /// Gets the visibility of the clicked legend. Determined by <see cref="CartesianSeries{TItem}.IsVisible" />. Always visible for Pie Charts.

Radzen.Blazor/LinearScale.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Globalization;
 using System.Linq;
 using System.Collections.Generic;
 
@@ -20,10 +21,10 @@ namespace Radzen.Blazor
 
             if (String.IsNullOrEmpty(format))
             {
-                return value.ToString();
+                return value.ToString() ?? String.Empty;
             }
 
-            return string.Format(format, value);
+            return string.Format(CultureInfo.InvariantCulture, format, value);
         }
 
         public override double Scale(double value, bool padding)
@@ -96,7 +97,7 @@ namespace Radzen.Blazor
             {
                 if (Step is IConvertible)
                 {
-                    step = Convert.ToDouble(Step);
+                    step = Convert.ToDouble(Step, CultureInfo.InvariantCulture);
                 }
             }
 
@@ -124,7 +125,7 @@ namespace Radzen.Blazor
 
             if (step == 0)
             {
-                throw new ArgumentOutOfRangeException("Step must be non-zero");
+                throw new ArgumentOutOfRangeException(nameof(distance), "Step must be non-zero");
             }
 
             return (start, end, Math.Abs(step));

Radzen.Blazor/ListBoxItemRenderEventArgs.cs

@@ -10,6 +10,6 @@ public class ListBoxItemRenderEventArgs<TValue> : DropDownBaseItemRenderEventArg
     /// <summary>
     /// Gets the ListBox.
     /// </summary>
-    public RadzenListBox<TValue> ListBox { get; internal set; }
+    public RadzenListBox<TValue>? ListBox { get; internal set; }
 }
 

Radzen.Blazor/LoadDataArgs.cs

@@ -23,11 +23,11 @@ public class LoadDataArgs
     /// <summary>
     /// Gets the sort expression as a string.
     /// </summary>
-    public string OrderBy { get; set; }
+    public string? OrderBy { get; set; }
 
-    private Func<string> getFilter;
+    private Func<string>? getFilter;
 
-    internal Func<string> GetFilter
+    internal Func<string>? GetFilter
     {
         get
         {
@@ -40,19 +40,19 @@ public class LoadDataArgs
         }
     }
 
-    private string filter;
+    private string? filter;
 
     /// <summary>
     /// Gets the filter expression as a string.
     /// </summary>
     /// <value>The filter.</value>
-    public string Filter
+    public string? Filter
     {
         get
         {
             if (filter == null && GetFilter != null)
             {
-                filter = GetFilter();
+                filter = GetFilter?.Invoke();
             }
             return filter;
         }
@@ -65,12 +65,12 @@ public class LoadDataArgs
     /// <summary>
     /// Gets the filter expression as a collection of filter descriptors.
     /// </summary>
-    public IEnumerable<FilterDescriptor> Filters { get; set; }
+    public IEnumerable<FilterDescriptor>? Filters { get; set; }
 
     /// <summary>
     /// Gets the sort expression as a collection of sort descriptors.
     /// </summary>
     /// <value>The sorts.</value>
-    public IEnumerable<SortDescriptor> Sorts { get; set; }
+    public IEnumerable<SortDescriptor>? Sorts { get; set; }
 }
 

Radzen.Blazor/LoginArgs.cs

@@ -8,12 +8,12 @@ public class LoginArgs
     /// <summary>
     /// Gets or sets the username.
     /// </summary>
-    public string Username { get; set; }
+    public string? Username { get; set; }
 
     /// <summary>
     /// Gets or sets the password.
     /// </summary>
-    public string Password { get; set; }
+    public string? Password { get; set; }
 
     /// <summary> 
     /// Gets or sets a value indicating whether the user wants to remember their credentials. 

Radzen.Blazor/MD5.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Globalization;
 using System.Linq;
 
 namespace Radzen;
@@ -59,6 +60,8 @@ public class MD5
     /// <returns>The MD5 hash as a string.</returns>
     public static string Calculate(byte[] input)
     {
+        ArgumentNullException.ThrowIfNull(input);
+
         uint a0 = 0x67452301;   // A
         uint b0 = 0xefcdab89;   // B
         uint c0 = 0x98badcfe;   // C
@@ -124,7 +127,7 @@ public class MD5
 
     private static string GetByteString(uint x)
     {
-        return String.Join("", BitConverter.GetBytes(x).Select(y => y.ToString("x2")));
+        return String.Join("", BitConverter.GetBytes(x).Select(y => y.ToString("x2", CultureInfo.InvariantCulture)));
     }
 }
 

Radzen.Blazor/Markdown/BlazorMarkdownRenderer.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Globalization;
 using System.Text.RegularExpressions;
 using Microsoft.AspNetCore.Components;
 using Microsoft.AspNetCore.Components.Rendering;
@@ -194,7 +195,7 @@ internal class BlazorMarkdownRenderer(BlazorMarkdownRendererOptions options, Ren
     /// <inheritdoc />
     public override void VisitLink(Link link)
     {
-        if (link.Destination.StartsWith("#"))
+        if (link.Destination?.StartsWith('#') == true)
         {
             builder.OpenComponent<RadzenAnchor>(0);
             builder.AddAttribute(0, "href", link.Destination);
@@ -210,7 +211,7 @@ internal class BlazorMarkdownRenderer(BlazorMarkdownRendererOptions options, Ren
         {
             builder.OpenComponent<RadzenLink>(0);
 
-            if (!HtmlSanitizer.IsDangerousUrl(link.Destination))
+            if (!string.IsNullOrEmpty(link.Destination) && !HtmlSanitizer.IsDangerousUrl(link.Destination))
             {
                 builder.AddAttribute(1, nameof(RadzenLink.Path), link.Destination);
             }
@@ -230,7 +231,7 @@ internal class BlazorMarkdownRenderer(BlazorMarkdownRendererOptions options, Ren
     {
         builder.OpenComponent<RadzenImage>(0);
 
-        if (!HtmlSanitizer.IsDangerousUrl(image.Destination))
+        if (!string.IsNullOrEmpty(image.Destination) && !HtmlSanitizer.IsDangerousUrl(image.Destination))
         {
             builder.AddAttribute(1, nameof(RadzenImage.Path), image.Destination);
         }
@@ -291,7 +292,7 @@ internal class BlazorMarkdownRenderer(BlazorMarkdownRendererOptions options, Ren
 
         if (match.Success)
         {
-            var markerId = Convert.ToInt32(match.Groups[1].Value);
+            var markerId = int.Parse(match.Groups[1].Value, CultureInfo.InvariantCulture);
             outlet(builder, markerId);
         }
         else if (options.AllowHtml)
@@ -349,11 +350,12 @@ internal class BlazorMarkdownRenderer(BlazorMarkdownRendererOptions options, Ren
     /// <inheritdoc />
     public override void VisitHtmlInline(HtmlInline htmlInline)
     {
+        if (htmlInline.Value == null) return;
         var match = OutletRegex.Match(htmlInline.Value);
 
         if (match.Success)
         {
-            var markerId = Convert.ToInt32(match.Groups[1].Value);
+            var markerId = Convert.ToInt32(match.Groups[1].Value, CultureInfo.InvariantCulture);
             outlet(builder, markerId);
             return;
         }
@@ -406,7 +408,7 @@ internal class BlazorMarkdownRenderer(BlazorMarkdownRendererOptions options, Ren
                 }
             }
 
-            if (html.EndsWith("/>") || IsVoidElement(tagName))
+            if (html.EndsWith("/>", StringComparison.Ordinal) || IsVoidElement(tagName))
             {
                 builder.CloseElement();
             }

Radzen.Blazor/Markdown/BlockContainer.cs

@@ -1,4 +1,5 @@
 
+using System;
 using System.Collections.Generic;
 
 namespace Radzen.Blazor.Markdown;
@@ -29,6 +30,7 @@ public abstract class BlockContainer : Block
     /// <returns>The added block.</returns>
     public virtual T Add<T>(T block) where T : Block
     {
+        ArgumentNullException.ThrowIfNull(block);
         children.Add(block);
 
         block.Parent = this;
@@ -43,6 +45,8 @@ public abstract class BlockContainer : Block
     /// <param name="target">The block to replace with.</param>
     public void Replace(Block source, Block target)
     {
+        ArgumentNullException.ThrowIfNull(source);
+        ArgumentNullException.ThrowIfNull(target);
         var index = children.IndexOf(source);
 
         if (index >= 0)

Radzen.Blazor/Markdown/BlockQuote.cs

@@ -1,3 +1,5 @@
+using System;
+
 namespace Radzen.Blazor.Markdown;
 
 
@@ -9,6 +11,7 @@ public class BlockQuote : BlockContainer
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitBlockQuote(this);
     }
 

Radzen.Blazor/Markdown/Code.cs

@@ -1,3 +1,5 @@
+using System;
+
 namespace Radzen.Blazor.Markdown;
 
 /// <summary>
@@ -14,6 +16,7 @@ public class Code(string value) : Inline
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitCode(this);
     }
 }

Radzen.Blazor/Markdown/Document.cs

@@ -1,3 +1,5 @@
+using System;
+
 namespace Radzen.Blazor.Markdown;
 
 /// <summary>
@@ -17,6 +19,7 @@ public class Document : BlockContainer
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitDocument(this);
     }
 

Radzen.Blazor/Markdown/Emphasis.cs

@@ -1,3 +1,5 @@
+using System;
+
 namespace Radzen.Blazor.Markdown;
 
 /// <summary>
@@ -8,6 +10,7 @@ public class Emphasis : InlineContainer
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitEmphasis(this);
     }
 }

Radzen.Blazor/Markdown/FencedCodeBlock.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Text.RegularExpressions;
 
 namespace Radzen.Blazor.Markdown;
@@ -10,17 +11,18 @@ public class FencedCodeBlock : Leaf
     /// <summary>
     /// The delimiter used to start and end the code block.
     /// </summary>
-    public string Delimiter { get; private set; }
+    public string? Delimiter { get; private set; }
     internal int Indent { get; private set; }
 
     /// <summary>
     /// The info string of the code block. This is the first line of the code block and is used to specify the language of the code block.
     /// </summary>
-    public string Info { get; private set; }
+    public string? Info { get; private set; }
 
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitFencedCodeBlock(this);
     }
 
@@ -29,7 +31,7 @@ public class FencedCodeBlock : Leaf
         base.Close(parser);
 
         // first line becomes info string
-        var newlinePos = Value.IndexOf('\n');
+        var newlinePos = Value.IndexOf('\n', StringComparison.Ordinal);
         var firstLine = Value[..newlinePos];
         Info = firstLine.Trim();
         Value = Value[(newlinePos + 1)..];
@@ -43,7 +45,7 @@ public class FencedCodeBlock : Leaf
 
         var match = ClosingFenceRegex.Match(line);
 
-        if (indent <= 3 && parser.PeekNonSpace() == Delimiter[0] && match.Success && match.Length >= Delimiter.Length)
+        if (indent <= 3 && Delimiter != null && parser.PeekNonSpace() == Delimiter[0] && match.Success && match.Length >= Delimiter.Length)
         {
             // closing fence - we're at end of line, so we can return
             parser.LastLineLength = parser.Offset + indent + match.Length;

Radzen.Blazor/Markdown/Heading.cs

@@ -1,4 +1,6 @@
 
+using System;
+
 namespace Radzen.Blazor.Markdown;
 
 /// <summary>
@@ -14,6 +16,7 @@ public abstract class Heading : Leaf
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitHeading(this);
     }
 

Radzen.Blazor/Markdown/HtmlBlock.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Text.RegularExpressions;
 
 namespace Radzen.Blazor.Markdown;
@@ -12,6 +13,7 @@ public class HtmlBlock : Leaf
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitHtmlBlock(this);
     }
 

Radzen.Blazor/Markdown/HtmlInline.cs

@@ -1,3 +1,5 @@
+using System;
+
 namespace Radzen.Blazor.Markdown;
 
 /// <summary>
@@ -8,12 +10,13 @@ public class HtmlInline : Inline
     /// <summary>
     /// Gets or sets the HTML element value.
     /// </summary>
-    public string Value { get; set; }
+    public string? Value { get; set; }
 
 
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitHtmlInline(this);
     }
 }

Radzen.Blazor/Markdown/HtmlSanitizer.cs

@@ -1,4 +1,5 @@
 
+using System;
 using System.Collections.Generic;
 using System.Text.RegularExpressions;
 
@@ -78,7 +79,7 @@ class HtmlSanitizer
 
         var safeAttributes = Regex.Replace(attributes, @"(\w+)\s*=\s*(""[^""]*""|'[^']*'|[^\s>]+)", SanitizeAttribute);
 
-        return $"<{(match.Value.StartsWith("</") ? "/" : "")}{tag}{safeAttributes}>";
+        return $"<{(match.Value.StartsWith("</", StringComparison.Ordinal) ? "/" : "")}{tag}{safeAttributes}>";
     }
 
     private string SanitizeAttribute(Match match)
@@ -128,9 +129,9 @@ class HtmlSanitizer
 
         var decoded = HtmlDecode(value).Trim().ToLowerInvariant();
 
-        return decoded.StartsWith("javascript:") ||
-               decoded.StartsWith("vbscript:") ||
-               decoded.StartsWith("data:text/html") ||
-               decoded.Contains("expression(");
+        return decoded.StartsWith("javascript:", StringComparison.Ordinal) ||
+               decoded.StartsWith("vbscript:", StringComparison.Ordinal) ||
+               decoded.StartsWith("data:text/html", StringComparison.Ordinal) ||
+               decoded.Contains("expression(", StringComparison.Ordinal);
     }
 }

Radzen.Blazor/Markdown/Image.cs

@@ -1,3 +1,5 @@
+using System;
+
 namespace Radzen.Blazor.Markdown;
 
 /// <summary>
@@ -8,16 +10,17 @@ public class Image : InlineContainer
     /// <summary>
     /// Gets or sets the destination (URL) of the image.
     /// </summary>
-    public string Destination { get; set; }
+    public string? Destination { get; set; }
 
     /// <summary>
     /// Gets or sets the alternative text of the image.
     /// </summary>
-    public string Title { get; set; }
+    public string? Title { get; set; }
 
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitImage(this);
     }
 }

Radzen.Blazor/Markdown/IndentedCodeBlock.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Linq;
 using System.Text.RegularExpressions;
 
@@ -11,6 +12,7 @@ public class IndentedCodeBlock : Leaf
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitIndentedCodeBlock(this);
     }
 

Radzen.Blazor/Markdown/InlineParser.cs

@@ -12,7 +12,7 @@ class InlineParser
         public char Char { get; set; }
         public int Length { get; set; }
         public int Position { get; set; }
-        public Text Node { get; set; }
+        public Text? Node { get; set; }
         public bool CanOpen { get; set; }
         public bool CanClose { get; set; }
         public bool Active { get; set; } = true;
@@ -296,7 +296,7 @@ class InlineParser
 
         var url = destination.ToString();
 
-        if (url.Contains(Space))
+        if (url.Contains(Space, StringComparison.Ordinal))
         {
             return false;
         }
@@ -778,7 +778,7 @@ class InlineParser
 
     private void ReplaceOpener(int openerIndex, InlineContainer parent)
     {
-        var startIndex = inlines.FindIndex(delimiters[openerIndex].Node.Equals);
+        var startIndex = delimiters[openerIndex].Node != null ? inlines.FindIndex(node => node.Equals(delimiters[openerIndex].Node)) : -1;
 
         ParseEmphasisAndStrong(openerIndex);
 
@@ -815,7 +815,7 @@ class InlineParser
 
         AddTextNode();
 
-        var startIndex = inlines.FindIndex(delimiters[openerIndex].Node.Equals);
+        var startIndex = delimiters[openerIndex].Node != null ? inlines.FindIndex(node => node.Equals(delimiters[openerIndex].Node)) : -1;
 
         var endIndex = inlines.Count - startIndex;
 
@@ -878,8 +878,8 @@ class InlineParser
             {
                 var closer = delimiters[closerIndex];
                 var opener = delimiters[openerIndex];
-                var startIndex = inlines.FindIndex(opener.Node.Equals);
-                var endIndex = inlines.FindIndex(closer.Node.Equals);
+                var startIndex = opener.Node != null ? inlines.FindIndex(opener.Node.Equals) : -1;
+                var endIndex = closer.Node != null ? inlines.FindIndex(closer.Node.Equals) : -1;
 
                 if (startIndex >= 0 && endIndex >= 0)
                 {
@@ -896,7 +896,7 @@ class InlineParser
 
                     opener.Length -= charsToConsume;
 
-                    if (opener.Length > 0)
+                    if (opener.Length > 0 && opener.Node != null)
                     {
                         opener.Node.Value = opener.Node.Value[..^charsToConsume];
                         startIndex += 1;
@@ -904,7 +904,7 @@ class InlineParser
 
                     closer.Length -= charsToConsume;
 
-                    if (closer.Length > 0)
+                    if (closer.Length > 0 && closer.Node != null)
                     {
                         closer.Node.Value = closer.Node.Value[..^charsToConsume];
                         endIndex -= 1;

Radzen.Blazor/Markdown/LineBreak.cs

@@ -1,3 +1,5 @@
+using System;
+
 namespace Radzen.Blazor.Markdown;
 
 /// <summary>
@@ -8,6 +10,7 @@ public class LineBreak : Inline
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitLineBreak(this);
     }
 }

Radzen.Blazor/Markdown/Link.cs

@@ -1,3 +1,5 @@
+using System;
+
 namespace Radzen.Blazor.Markdown;
 
 /// <summary>
@@ -8,16 +10,17 @@ public class Link : InlineContainer
     /// <summary>
     /// Gets or sets the destination (URL) of the link.
     /// </summary>
-    public string Destination { get; set; }
+    public string? Destination { get; set; }
 
     /// <summary>
     /// Gets or sets the link title.
     /// </summary>
-    public string Title { get; set; }
+    public string? Title { get; set; }
 
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitLink(this);
     }
 }

Radzen.Blazor/Markdown/LinkReference.cs

@@ -2,6 +2,6 @@ namespace Radzen.Blazor.Markdown;
 
 class LinkReference
 {
-    public string Destination { get; set; }
-    public string Title { get; set; }
+    public string? Destination { get; set; }
+    public string? Title { get; set; }
 }

Radzen.Blazor/Markdown/ListBase.cs

@@ -17,7 +17,7 @@ public abstract class List : BlockContainer
     /// </summary>
     public bool Tight { get; set; } = true;
     internal int Padding { get; set; }
-    internal string Delimiter { get; set; }
+    internal string? Delimiter { get; set; }
 
     internal override BlockMatch Matches(BlockParser parser)
     {

Radzen.Blazor/Markdown/ListItem.cs

@@ -1,3 +1,5 @@
+using System;
+using System.Globalization;
 using System.Text.RegularExpressions;
 
 namespace Radzen.Blazor.Markdown;
@@ -12,6 +14,7 @@ public class ListItem : BlockContainer
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitListItem(this);
     }
 
@@ -126,7 +129,7 @@ public class ListItem : BlockContainer
                 var list = new OrderedList
                 {
                     MarkerOffset = parser.Indent,
-                    Start = int.Parse(match.Groups[1].Value),
+                    Start = int.Parse(match.Groups[1].Value, CultureInfo.InvariantCulture),
                     Delimiter = match.Groups[2].Value
                 };
                 data = list;

Radzen.Blazor/Markdown/NodeVisitorBase.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 
 namespace Radzen.Blazor.Markdown;
@@ -11,32 +12,56 @@ public abstract class NodeVisitorBase : INodeVisitor
     /// <summary>
     /// Visits a block quote by visiting its children.
     /// </summary>
-    public virtual void VisitBlockQuote(BlockQuote blockQuote) => VisitChildren(blockQuote.Children);
+    public virtual void VisitBlockQuote(BlockQuote blockQuote)
+    {
+        ArgumentNullException.ThrowIfNull(blockQuote);
+        VisitChildren(blockQuote.Children);
+    }
 
     /// <summary>
     /// Visits a document by visiting its children.
     /// </summary>
-    public virtual void VisitDocument(Document document) => VisitChildren(document.Children);
+    public virtual void VisitDocument(Document document)
+    {
+        ArgumentNullException.ThrowIfNull(document);
+        VisitChildren(document.Children);
+    }
 
     /// <summary>
     /// Visits a heading by visiting its children.
     /// </summary>
-    public virtual void VisitHeading(Heading heading) => VisitChildren(heading.Children);
+    public virtual void VisitHeading(Heading heading)
+    {
+        ArgumentNullException.ThrowIfNull(heading);
+        VisitChildren(heading.Children);
+    }
 
     /// <summary>
     /// Visits a list item by visiting its children.
     /// </summary>
-    public virtual void VisitListItem(ListItem listItem) => VisitChildren(listItem.Children);
+    public virtual void VisitListItem(ListItem listItem)
+    {
+        ArgumentNullException.ThrowIfNull(listItem);
+        VisitChildren(listItem.Children);
+    }
 
     /// <summary>
     /// Visits an ordered list by visiting its children.
     /// </summary>
-    public virtual void VisitOrderedList(OrderedList orderedList) => VisitChildren(orderedList.Children);
+    public virtual void VisitOrderedList(OrderedList orderedList)
+    {
+        ArgumentNullException.ThrowIfNull(orderedList);
+        VisitChildren(orderedList.Children);
+    }
 
     /// <summary>
     /// Visits a paragraph by visiting its children.
     /// </summary>
-    public virtual void VisitParagraph(Paragraph paragraph) => VisitChildren(paragraph.Children);
+    public virtual void VisitParagraph(Paragraph paragraph)
+    {
+        ArgumentNullException.ThrowIfNull(paragraph);
+        VisitChildren(paragraph.Children);
+    }
 
     /// <summary>
     /// Visits a thematic break.
@@ -83,27 +108,47 @@ public abstract class NodeVisitorBase : INodeVisitor
     /// <summary>
     /// Visits an ordered list by visiting its children.
     /// </summary>
-    public virtual void VisitUnorderedList(UnorderedList unorderedList) => VisitChildren(unorderedList.Children);
+    public virtual void VisitUnorderedList(UnorderedList unorderedList)
+    {
+        ArgumentNullException.ThrowIfNull(unorderedList);
+        VisitChildren(unorderedList.Children);
+    }
 
     /// <summary>
     /// Visits an emphasis by visiting its children.
     /// </summary>
-    public virtual void VisitEmphasis(Emphasis emphasis) => VisitChildren(emphasis.Children);
+    public virtual void VisitEmphasis(Emphasis emphasis)
+    {
+        ArgumentNullException.ThrowIfNull(emphasis);
+        VisitChildren(emphasis.Children);
+    }
 
     /// <summary>
     /// Visits a strong by visiting its children.
     /// </summary>
-    public virtual void VisitStrong(Strong strong) => VisitChildren(strong.Children);
+    public virtual void VisitStrong(Strong strong)
+    {
+        ArgumentNullException.ThrowIfNull(strong);
+        VisitChildren(strong.Children);
+    }
 
     /// <summary>
     /// Visits a link by visiting its children.
     /// </summary>
-    public virtual void VisitLink(Link link) => VisitChildren(link.Children);
+    public virtual void VisitLink(Link link)
+    {
+        ArgumentNullException.ThrowIfNull(link);
+        VisitChildren(link.Children);
+    }
 
     /// <summary>
     /// Visits an image by visiting its children.
     /// </summary>
-    public virtual void VisitImage(Image image) => VisitChildren(image.Children);
+    public virtual void VisitImage(Image image)
+    {
+        ArgumentNullException.ThrowIfNull(image);
+        VisitChildren(image.Children);
+    }
 
     /// <summary>
     /// Visits a code block.
@@ -129,28 +174,45 @@ public abstract class NodeVisitorBase : INodeVisitor
     /// <summary>
     /// Visits a table.
     /// </summary>
-    public virtual void VisitTable(Table table) => VisitChildren(table.Rows);
+    public virtual void VisitTable(Table table)
+    {
+        ArgumentNullException.ThrowIfNull(table);
+        VisitChildren(table.Rows);
+    }
 
     /// <summary>
     /// Visits a table header row by visiting its children.
     /// </summary>
-    public virtual void VisitTableHeaderRow(TableHeaderRow header) => VisitChildren(header.Cells);
+    public virtual void VisitTableHeaderRow(TableHeaderRow header)
+    {
+        ArgumentNullException.ThrowIfNull(header);
+        VisitChildren(header.Cells);
+    }
 
     /// <summary>
     /// Visits a table row by visiting its children.
     /// </summary>
-    public virtual void VisitTableRow(TableRow row) => VisitChildren(row.Cells);
+    public virtual void VisitTableRow(TableRow row)
+    {
+        ArgumentNullException.ThrowIfNull(row);
+        VisitChildren(row.Cells);
+    }
 
     /// <summary>
     /// Visits a table cell by visiting its children.
     /// </summary>
-    public virtual void VisitTableCell(TableCell cell) => VisitChildren(cell.Children);
+    public virtual void VisitTableCell(TableCell cell)
+    {
+        ArgumentNullException.ThrowIfNull(cell);
+        VisitChildren(cell.Children);
+    }
 
     /// <summary>
     /// Visits a collection of nodes.
     /// </summary>
     protected void VisitChildren(IEnumerable<INode> children)
     {
+        ArgumentNullException.ThrowIfNull(children);
         foreach (var node in children)
         {
             node.Accept(this);

Radzen.Blazor/Markdown/OrderedList.cs

@@ -1,3 +1,5 @@
+using System;
+
 namespace Radzen.Blazor.Markdown;
 
 /// <summary>
@@ -8,6 +10,7 @@ public class OrderedList : List
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitOrderedList(this);
     }
 

Radzen.Blazor/Markdown/Paragraph.cs

@@ -1,4 +1,6 @@
 
+using System;
+
 namespace Radzen.Blazor.Markdown;
 
 /// <summary>
@@ -9,6 +11,7 @@ public class Paragraph : Leaf
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitParagraph(this);
     }
 

Radzen.Blazor/Markdown/SoftLineBreak.cs

@@ -1,3 +1,5 @@
+using System;
+
 namespace Radzen.Blazor.Markdown;
 
 /// <summary>
@@ -8,6 +10,7 @@ public class SoftLineBreak : Inline
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitSoftLineBreak(this);
     }
 }

Radzen.Blazor/Markdown/Strong.cs

@@ -1,3 +1,5 @@
+using System;
+
 namespace Radzen.Blazor.Markdown;
 
 /// <summary>
@@ -8,6 +10,7 @@ public class Strong : InlineContainer
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitStrong(this);
     }
 }

Radzen.Blazor/Markdown/Table.cs

@@ -19,6 +19,7 @@ public class Table : Leaf
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitTable(this);
     }
 
@@ -137,7 +138,7 @@ public class Table : Leaf
 
         // Check if the line contains a pipe character to be more specific about table delimiters
         // This helps avoid misinterpreting heading delimiters as table delimiters
-        if (!line.Contains('|') && !line.Contains(':'))
+        if (!line.Contains('|', StringComparison.Ordinal) && !line.Contains(':', StringComparison.Ordinal))
         {
             return BlockStart.Skip;
         }

Radzen.Blazor/Markdown/TableCell.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 
 namespace Radzen.Blazor.Markdown;
@@ -47,6 +48,7 @@ public class TableCell : INode, IBlockInlineContainer
     /// <inheritdoc />
     public void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitTableCell(this);
     }
 }

Radzen.Blazor/Markdown/TableHeaderRow.cs

@@ -1,3 +1,5 @@
+using System;
+
 namespace Radzen.Blazor.Markdown;
 
 /// <summary>
@@ -8,6 +10,7 @@ public class TableHeaderRow : TableRow
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitTableHeaderRow(this);
     }
 }

Radzen.Blazor/Markdown/TableRow.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Collections.Generic;
 
 namespace Radzen.Blazor.Markdown;
@@ -28,6 +29,7 @@ public class TableRow : INode
     /// <inheritdoc />
     public virtual void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitTableRow(this);
     }
 }

Radzen.Blazor/Markdown/Text.cs

@@ -1,3 +1,5 @@
+using System;
+
 namespace Radzen.Blazor.Markdown;
 
 /// <summary>
@@ -13,6 +15,7 @@ public class Text(string value) : Inline
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitText(this);
     }
 }

Radzen.Blazor/Markdown/ThematicBreak.cs

@@ -1,3 +1,4 @@
+using System;
 using System.Text.RegularExpressions;
 
 namespace Radzen.Blazor.Markdown;
@@ -12,6 +13,7 @@ public class ThematicBreak : Block
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitThematicBreak(this);
     }
 

Radzen.Blazor/Markdown/UnorderedList.cs

@@ -1,3 +1,5 @@
+using System;
+
 namespace Radzen.Blazor.Markdown;
 
 /// <summary>
@@ -8,6 +10,7 @@ public class UnorderedList : List
     /// <inheritdoc />
     public override void Accept(INodeVisitor visitor)
     {
+        ArgumentNullException.ThrowIfNull(visitor);
         visitor.VisitUnorderedList(this);
     }
 }

Radzen.Blazor/MenuItemEventArgs.cs

@@ -10,16 +10,16 @@ public class MenuItemEventArgs : MouseEventArgs
     /// <summary>
     /// Gets text of the clicked item.
     /// </summary>
-    public string Text { get; internal set; }
+    public string? Text { get; internal set; }
 
     /// <summary>
     /// Gets the value of the clicked item.
     /// </summary>
-    public object Value { get; internal set; }
+    public object? Value { get; internal set; }
 
     /// <summary>
     /// Gets the path path of the clicked item.
     /// </summary>
-    public string Path { get; internal set; }
+    public string? Path { get; internal set; }
 }