[leak-fix] Fix ListView.RefreshCommand memory leak (Fixes #36344)

src/Controls/src/Core/ListView/ListView.cs

@@ -97,6 +97,8 @@ public class ListView : ItemsView<Cell>, IListViewController, IElementConfigurat
 		int _previousGroupSelected = -1;
 		int _previousRowSelected = -1;
 
+		WeakCommandSubscription _refreshCommandSubscription;
+
 		/// <summary>
 		///     Controls whether anything happens in BeginRefresh(), is set based on RefreshCommand.CanExecute
 		/// </summary>
@@ -763,12 +765,13 @@ void OnRefreshCommandChanged(ICommand oldCommand, ICommand newCommand)
 		{
 			if (oldCommand != null)
 			{
-				oldCommand.CanExecuteChanged -= OnCommandCanExecuteChanged;
+				_refreshCommandSubscription?.Dispose();
+				_refreshCommandSubscription = null;
 			}
 
 			if (newCommand != null)
 			{
-				newCommand.CanExecuteChanged += OnCommandCanExecuteChanged;
+				_refreshCommandSubscription = new WeakCommandSubscription(this, newCommand, OnCommandCanExecuteChanged);
 				RefreshAllowed = newCommand.CanExecute(null);
 			}
 			else

src/Controls/tests/Core.UnitTests/ListViewTests.cs

@@ -35,6 +35,43 @@ public void TestConstructor()
 			Assert.Equal(LayoutOptions.FillAndExpand, listView.VerticalOptions);
 		}
 
+		[Fact]
+		public async Task RefreshCommandDoesNotLeakListView()
+		{
+			// A long-lived command whose CanExecuteChanged is a *strong* .NET event, as with a
+			// custom ICommand or CommunityToolkit's RelayCommand. (Microsoft.Maui.Controls.Command
+			// routes CanExecuteChanged through a WeakEventManager and would not reproduce the leak.)
+			ICommand command = new StrongCanExecuteCommand();
+
+			// Create the ListView in a separate method so no local in this frame roots it.
+			WeakReference CreateReference()
+			{
+				var listView = new ListView { RefreshCommand = command };
+				return new WeakReference(listView);
+			}
+
+			WeakReference reference = CreateReference();
+
+			await TestHelpers.Collect();
+
+			// The command out-lives the ListView; subscribing to its CanExecuteChanged must not
+			// keep the ListView (and its cells, templates and binding context) alive.
+			Assert.False(await reference.WaitForCollect(), "ListView should not be alive!");
+
+			GC.KeepAlive(command);
+		}
+
+		sealed class StrongCanExecuteCommand : ICommand
+		{
+			public event EventHandler CanExecuteChanged;
+
+			public bool CanExecute(object parameter) => true;
+
+			public void Execute(object parameter) { }
+
+			public void ChangeCanExecute() => CanExecuteChanged?.Invoke(this, EventArgs.Empty);
+		}
+
 		internal class ListItem
 		{
 			public string Name { get; set; }