radzen-blazor/Radzen.Blazor/RadzenContextMenu.razor.cs

using Microsoft.AspNetCore.Components;
using Microsoft.AspNetCore.Components.Web;
using Microsoft.JSInterop;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;

namespace Radzen.Blazor
{
    /// <summary>
    /// RadzenContextMenu component.
    /// </summary>
    /// <example>
    /// <code>
    /// @inject ContextMenuService ContextMenuService
    /// 
    /// &lt;RadzenButton Text="Show context menu" ContextMenu=@(args => ShowContextMenuWithItems(args)) /&gt;
    /// 
    /// @code {
    ///   void ShowContextMenuWithItems(MouseEventArgs args)
    ///   {
    ///     ContextMenuService.Open(args,
    ///         new List&lt;ContextMenuItem&gt; {
    ///             new ContextMenuItem() { Text = "Context menu item 1", Value = 1 },
    ///             new ContextMenuItem() { Text = "Context menu item 2", Value = 2 },
    ///             new ContextMenuItem() { Text = "Context menu item 3", Value = 3 },
    ///      }, OnMenuItemClick);
    ///   }
    ///   
    ///   void OnMenuItemClick(MenuItemEventArgs args)
    ///   {
    ///     Console.WriteLine($"Menu item with Value={args.Value} clicked");
    ///   }
    /// }
    /// </code>
    /// </example>
    public partial class RadzenContextMenu : IAsyncDisposable
    {
        /// <summary>
        /// Gets or sets the unique identifier.
        /// </summary>
        /// <value>The unique identifier.</value>
        public string? UniqueID { get; set; }

        /// <summary>
        /// Gets or sets the ContextMenuService.
        /// </summary>
        /// <value>The ContextMenuService.</value>
        [Inject] private ContextMenuService? Service { get; set; }

        List<ContextMenu> menus = new List<ContextMenu>();

        /// <summary>
        /// Opens the menu.
        /// </summary>
        /// <param name="args">The <see cref="MouseEventArgs"/> instance containing the event data.</param>
        /// <param name="options">The options.</param>
        public async Task Open(MouseEventArgs args, ContextMenuOptions options)
        {
            menus.Clear();
            menus.Add(new ContextMenu() { Options = options, MouseEventArgs = args });

            await InvokeAsync(() => { StateHasChanged(); });
        }

        private bool IsJSRuntimeAvailable { get; set; }

        /// <inheritdoc />
        protected override async Task OnAfterRenderAsync(bool firstRender)
        {
            IsJSRuntimeAvailable = true;

            var menu = menus.LastOrDefault();
            if (menu != null && menu.MouseEventArgs != null)
            {
                await JSRuntime.InvokeVoidAsync("Radzen.openContextMenu",
                    menu.MouseEventArgs.ClientX,
                    menu.MouseEventArgs.ClientY,
                    UniqueID,
                    Reference,
                    "RadzenContextMenu.CloseMenu");
            }
        }

        private DotNetObjectReference<RadzenContextMenu>? reference;

        /// <summary>
        /// Gets the reference for the current component.
        /// </summary>
        /// <value>The reference.</value>
        protected DotNetObjectReference<RadzenContextMenu> Reference
        {
            get
            {
                if (reference == null)
                {
                    reference = DotNetObjectReference.Create(this);
                }

                return reference;
            }
        }

        /// <summary>
        /// Closes this instance.
        /// </summary>
        public async Task Close()
        {
            var lastTooltip = menus.LastOrDefault();
            if (lastTooltip != null)
            {
                menus.Remove(lastTooltip);
                await JSRuntime.InvokeVoidAsync("Radzen.closePopup", UniqueID);
            }

            await InvokeAsync(() => { StateHasChanged(); });
        }

        /// <summary>
        /// Closes this instance.
        /// </summary>
        [JSInvokable("RadzenContextMenu.CloseMenu")]
        public void CloseMenu()
        {
            Service?.Close(); 
        }

        /// <inheritdoc />
        public async ValueTask DisposeAsync()
        {
            while (menus.Count != 0)
            {
                await Close();
            }

            reference?.Dispose();
            reference = null;

            if (IsJSRuntimeAvailable)
            {
                try 
                {
                    await JSRuntime.InvokeVoidAsync("Radzen.destroyPopup", UniqueID);
                }
                catch
                { }
            }

            if (Service != null)
            {
                Service.OnOpen -= OnOpen;
                Service.OnClose -= OnClose;
                Service.OnNavigate -= OnNavigate;
            }
        }

        /// <inheritdoc />
        protected override void OnInitialized()
        {
            UniqueID = Convert.ToBase64String(Guid.NewGuid().ToByteArray()).Replace("/", "-", StringComparison.Ordinal).Replace("+", "-", StringComparison.Ordinal).Substring(0, 10);

            if (Service != null)
            {
                Service.OnOpen += OnOpen;
                Service.OnClose += OnClose;
                Service.OnNavigate += OnNavigate;
            }
        }

        void OnOpen(MouseEventArgs args, ContextMenuOptions options)
        {
            Open(args, options).ConfigureAwait(false);
        }

        void OnClose()
        {
            Close().ConfigureAwait(false);
        }

        void OnNavigate()
        {
            if (UniqueID != null)
            {
                JSRuntime.InvokeVoid("Radzen.closePopup", UniqueID);
            }
        }
    }
}