[Blazor] Better implementation of EventCallback.Equals #53361 (#53395)

Author: JelleHissink

src/Components/Components/src/EventCallback.cs

@@ -80,5 +80,5 @@ public override int GetHashCode()
     public override bool Equals(object? obj)
         => obj is EventCallback other
         && ReferenceEquals(Receiver, other.Receiver)
-        && ReferenceEquals(Delegate, other.Delegate);
+        && (Delegate?.Equals(other.Delegate) ?? (other.Delegate == null));
 }

src/Components/Components/src/EventCallbackOfT.cs

@@ -80,5 +80,5 @@ public override int GetHashCode()
     public override bool Equals(object? obj)
         => obj is EventCallback<TValue> other
         && ReferenceEquals(Receiver, other.Receiver)
-        && ReferenceEquals(Delegate, other.Delegate);
+        && (Delegate?.Equals(other.Delegate) ?? (other.Delegate == null));
 }

src/Components/Components/test/EventCallbackTest.cs

@@ -271,6 +271,24 @@ await Assert.ThrowsAsync<ArgumentException>(() =>
         });
     }
 
+    [Fact]
+    public void EventCallbackOf_Equals_WhenANewDelegateIsCreated()
+    {
+        // Arrange
+        var component = new EventCountingComponent();
+
+        var delegate_1 = (EventArgs _) => { };
+        var delegate_2 = (MulticastDelegate)MulticastDelegate.CreateDelegate(typeof(Action<EventArgs>), delegate_1.Target, delegate_1.Method);
+        var eventcallback_1 = new EventCallback(component, delegate_1);
+        var eventcallback_2 = new EventCallback(component, delegate_2);
+
+        // Act
+        var result = eventcallback_1.Equals(eventcallback_2);
+
+        // Assert
+        Assert.True(result);
+    }
+
     [Fact]
     public async Task EventCallbackOfT_Action_Null()
     {
@@ -415,6 +433,24 @@ public async Task EventCallbackOfT_FuncTTask_Arg()
         Assert.Equal(1, component.Count);
     }
 
+    [Fact]
+    public void EventCallbackOfT_Equals_WhenANewDelegateIsCreated()
+    {
+        // Arrange
+        var component = new EventCountingComponent();
+
+        var delegate_1 = (EventArgs _) => { };
+        var delegate_2 = (MulticastDelegate)MulticastDelegate.CreateDelegate(typeof(Action<EventArgs>), delegate_1.Target, delegate_1.Method);
+        var eventcallback_1 = new EventCallback<EventArgs>(component, delegate_1);
+        var eventcallback_2 = new EventCallback<EventArgs>(component, delegate_2);
+
+        // Act
+        var result = eventcallback_1.Equals(eventcallback_2);
+
+        // Assert
+        Assert.True(result);
+    }
+
     private class EventCountingComponent : IComponent, IHandleEvent
     {
         public int Count;