From 4d9a9c9ac2ecff8339578e9ce8bbeececdd2ec99 Mon Sep 17 00:00:00 2001
From: Petar Slavov <89679515+PetarSlavov@users.noreply.github.com>
Date: Fri, 15 Aug 2025 09:28:52 +0300
Subject: [PATCH] Add GetProperty that supports retrieval of interface
 properties.  (#2255)

* Introduces a new static method `GetProperty` in the `Radzen.PropertyAccess` class to retrieve properties by name, including support for interfaces. Updates `DropDownBase.cs` to utilize this new method, enabling property retrieval for collections of interfaces in multiselect DropDowns.

* Add unit tests for property resolution in interfaces

Implemented unit tests in `PropertyAccessTests.cs` to verify
the resolution of `Description`, `Name`, and `Id` properties
from the interfaces `ISimpleInterface`, `ISimpleNestedInterface`,
and `ISimpleBaseInterface`. Defined the interfaces to support
the tests for the `GetProperty` method functionality.
---
 Radzen.Blazor.Tests/PropertyAccessTests.cs | 38 ++++++++++++++++++++++
 Radzen.Blazor/Common.cs                    | 26 +++++++++++++++
 Radzen.Blazor/DropDownBase.cs              |  6 ++--
 3 files changed, 68 insertions(+), 2 deletions(-)

diff --git a/Radzen.Blazor.Tests/PropertyAccessTests.cs b/Radzen.Blazor.Tests/PropertyAccessTests.cs
index 727aa2b8..fc05575c 100644
--- a/Radzen.Blazor.Tests/PropertyAccessTests.cs
+++ b/Radzen.Blazor.Tests/PropertyAccessTests.cs
@@ -113,5 +113,43 @@ namespace Radzen.Blazor.Tests
         {
             public List<string> Values { get; set; }
         }
+
+        [Fact]
+        public void GetProperty_Should_Resolve_DescriptionProperty()
+        {
+            var descriptionProperty = PropertyAccess.GetProperty(typeof(ISimpleInterface), nameof(ISimpleInterface.Description));
+
+            Assert.NotNull(descriptionProperty);
+        }
+
+        [Fact]
+        public void GetProperty_Should_Resolve_NameProperty()
+        {
+            var nameProperty = PropertyAccess.GetProperty(typeof(ISimpleInterface), nameof(ISimpleInterface.Name));
+
+            Assert.NotNull(nameProperty);
+        }
+
+        [Fact]
+        public void GetProperty_Should_Resolve_IdProperty()
+        {
+            var idProperty = PropertyAccess.GetProperty(typeof(ISimpleInterface), nameof(ISimpleBaseInterface.Id));
+            Assert.NotNull(idProperty);
+        }
+
+        interface ISimpleInterface : ISimpleNestedInterface
+        {
+            string Description { get; set; }
+        }
+
+        interface ISimpleNestedInterface : ISimpleBaseInterface
+        {
+            string Name { get; set; }
+        }
+
+        interface ISimpleBaseInterface
+        {
+            int Id { get; set; }
+        }
     }
 }
diff --git a/Radzen.Blazor/Common.cs b/Radzen.Blazor/Common.cs
index c6cd80f9..94a752e4 100644
--- a/Radzen.Blazor/Common.cs
+++ b/Radzen.Blazor/Common.cs
@@ -3498,6 +3498,32 @@ namespace Radzen
             return null;
         }
 
+        /// <summary>
+        /// Gets the property by its name. If the type is an interface, it will search through all interfaces implemented by the type.
+        /// </summary>
+        /// <param name="type">The type.</param>
+        /// <param name="property">The property.</param>
+        /// <returns>PropertyInfo.</returns>
+        public static PropertyInfo GetProperty(Type type, string property)
+        {
+            if (type.IsInterface)
+            {
+                var interfaces = type.GetInterfaces();
+
+                foreach (var @interface in interfaces)
+                {
+                    var propertyInfo = @interface.GetProperty(property);
+
+                    if (propertyInfo != null)
+                    {
+                        return propertyInfo;
+                    }
+                }
+            }
+
+            return type.GetProperty(property);
+        }
+
         /// <summary>
         /// Gets the dynamic property expression when binding to IDictionary.
         /// </summary>
diff --git a/Radzen.Blazor/DropDownBase.cs b/Radzen.Blazor/DropDownBase.cs
index ec47a904..13532a0e 100644
--- a/Radzen.Blazor/DropDownBase.cs
+++ b/Radzen.Blazor/DropDownBase.cs
@@ -318,7 +318,8 @@ namespace Radzen
 
             if (!string.IsNullOrEmpty(ValueProperty))
             {
-                System.Reflection.PropertyInfo pi = PropertyAccess.GetElementType(Data.GetType()).GetProperty(ValueProperty);
+                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);
             }
             else
@@ -1167,7 +1168,8 @@ namespace Radzen
 
                 if (!string.IsNullOrEmpty(ValueProperty))
                 {
-                    System.Reflection.PropertyInfo pi = PropertyAccess.GetElementType(Data.GetType()).GetProperty(ValueProperty);
+                    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);
                 }
                 else