Refactor ItemsLayout handling: dynamic default + virtual view-managed subscriptions v2

src/Controls/src/Core/Handlers/Items/Android/IMauiRecyclerView.cs

@@ -1,4 +1,6 @@
 #nullable disable
+using System.ComponentModel;
+
 namespace Microsoft.Maui.Controls.Handlers.Items
 {
 	public interface IMauiRecyclerView<TItemsView> where TItemsView : ItemsView
@@ -31,4 +33,10 @@ public interface IMauiRecyclerView<TItemsView> where TItemsView : ItemsView
 
 		public void UpdateCanReorderItems();
 	}
+
+	internal interface IMauiRecyclerViewWithUpdates<TItemsView> : IMauiRecyclerView<TItemsView> where TItemsView : ItemsView
+	{
+		void UpdateItemsLayoutProperties(PropertyChangedEventArgs args);
+	}
+
 }

src/Controls/src/Core/Handlers/Items/Android/MauiRecyclerView.cs

@@ -15,7 +15,7 @@
 namespace Microsoft.Maui.Controls.Handlers.Items
 {
 
-	public class MauiRecyclerView<TItemsView, TAdapter, TItemsViewSource> : RecyclerView, IMauiRecyclerView<TItemsView>
+	public class MauiRecyclerView<TItemsView, TAdapter, TItemsViewSource> : RecyclerView, IMauiRecyclerViewWithUpdates<TItemsView>
 		where TItemsView : ItemsView
 		where TAdapter : ItemsViewAdapter<TItemsView, TItemsViewSource>
 		where TItemsViewSource : IItemsViewSource
@@ -43,10 +43,9 @@ public class MauiRecyclerView<TItemsView, TAdapter, TItemsViewSource> : Recycler
 
 		ItemTouchHelper _itemTouchHelper;
 		SimpleItemTouchHelperCallback _itemTouchHelperCallback;
-		WeakNotifyPropertyChangedProxy _layoutPropertyChangedProxy;
-		PropertyChangedEventHandler _layoutPropertyChanged;
 
-		~MauiRecyclerView() => _layoutPropertyChangedProxy?.Unsubscribe();
+		//TODO: Remove this in .NET 10
+		~MauiRecyclerView() { }
 
 		public MauiRecyclerView(Context context, Func<IItemsLayout> getItemsLayout, Func<TAdapter> getAdapter) : base(new ContextThemeWrapper(context, Resource.Style.collectionViewTheme))
 		{
@@ -59,13 +58,6 @@ public MauiRecyclerView(Context context, Func<IItemsLayout> getItemsLayout, Func
 
 		public virtual void TearDownOldElement(TItemsView oldElement)
 		{
-			// Stop listening for layout property changes
-			if (_layoutPropertyChangedProxy is not null)
-			{
-				_layoutPropertyChangedProxy.Unsubscribe();
-				_layoutPropertyChanged = null;
-			}
-
 			// Stop listening for ScrollTo requests
 			oldElement.ScrollToRequested -= ScrollToRequested;
 
@@ -292,17 +284,9 @@ public virtual void UpdateLayoutManager()
 			{
 				return;
 			}
-
-			_layoutPropertyChangedProxy?.Unsubscribe();
+
 			ItemsLayout = itemsLayout;
 
-			// Keep track of the ItemsLayout's property changes
-			if (ItemsLayout is not null)
-			{
-				_layoutPropertyChanged ??= LayoutPropertyChanged;
-				_layoutPropertyChangedProxy = new WeakNotifyPropertyChangedProxy(ItemsLayout, _layoutPropertyChanged);
-			}
-
 			SetLayoutManager(SelectLayoutManager(ItemsLayout));
 
 			UpdateFlowDirection();
@@ -512,20 +496,26 @@ protected virtual void ScrollToRequested(object sender, ScrollToRequestEventArgs
 			ScrollTo(args);
 		}
 
+		//TODO: Remove this in .NET 10
 		protected virtual void LayoutPropertyChanged(object sender, PropertyChangedEventArgs propertyChanged)
 		{
-			if (propertyChanged.Is(GridItemsLayout.SpanProperty))
+		}
+
+		void IMauiRecyclerViewWithUpdates<TItemsView>.UpdateItemsLayoutProperties(PropertyChangedEventArgs args)
+		{
+
+			if (args.Is(GridItemsLayout.SpanProperty))
 			{
 				if (GetLayoutManager() is GridLayoutManager gridLayoutManager)
 				{
 					gridLayoutManager.SpanCount = ((GridItemsLayout)ItemsLayout).Span;
 				}
 			}
-			else if (propertyChanged.IsOneOf(Microsoft.Maui.Controls.ItemsLayout.SnapPointsTypeProperty, Microsoft.Maui.Controls.ItemsLayout.SnapPointsAlignmentProperty))
+			else if (args.IsOneOf(Microsoft.Maui.Controls.ItemsLayout.SnapPointsTypeProperty, Microsoft.Maui.Controls.ItemsLayout.SnapPointsAlignmentProperty))
 			{
 				UpdateSnapBehavior();
 			}
-			else if (propertyChanged.IsOneOf(LinearItemsLayout.ItemSpacingProperty,
+			else if (args.IsOneOf(LinearItemsLayout.ItemSpacingProperty,
 				GridItemsLayout.HorizontalItemSpacingProperty, GridItemsLayout.VerticalItemSpacingProperty))
 			{
 				UpdateItemSpacing();

src/Controls/src/Core/Handlers/Items/CarouselViewHandler.Android.cs

@@ -1,4 +1,5 @@
 #nullable disable
+using System.ComponentModel;
 using Android.Views;
 using AndroidX.RecyclerView.Widget;
 using Microsoft.Maui.Graphics;
@@ -62,6 +63,15 @@ internal static void MapItemsLayout(CarouselViewHandler handler, CarouselView ca
 			}
 		}
 
+		static void MapItemsLayoutPropertyChanged(CarouselViewHandler handler, CarouselView view, object args)
+		{
+			if (handler.PlatformView is IMauiRecyclerViewWithUpdates<CarouselView> recyclerView &&
+			    args is PropertyChangedEventArgs propertyChanged)
+			{
+				recyclerView.UpdateItemsLayoutProperties(propertyChanged);
+			}
+		}
+
 		public override Size GetDesiredSize(double widthConstraint, double heightConstraint)
 		{
 			_widthConstraint = widthConstraint;

src/Controls/src/Core/Handlers/Items/CarouselViewHandler.Standard.cs

@@ -16,5 +16,6 @@ public static void MapIsBounceEnabled(CarouselViewHandler handler, CarouselView
 		public static void MapIsSwipeEnabled(CarouselViewHandler handler, CarouselView carouselView) { }
 		public static void MapPeekAreaInsets(CarouselViewHandler handler, CarouselView carouselView) { }
 		public static void MapLoop(CarouselViewHandler handler, CarouselView carouselView) { }
+		static void MapItemsLayoutPropertyChanged(CarouselViewHandler handler, CarouselView view, object args){ }
 	}
 }

src/Controls/src/Core/Handlers/Items/CarouselViewHandler.Tizen.cs

@@ -38,5 +38,10 @@ public static void MapItemsLayout(CarouselViewHandler handler, CarouselView item
 		{
 			(handler.PlatformView as MauiCarouselView)?.UpdateLayoutManager();
 		}
+
+		static void MapItemsLayoutPropertyChanged(CarouselViewHandler handler, CarouselView view, object args)
+		{
+			(handler.PlatformView as MauiCarouselView)?.UpdateLayoutManager();
+		}
 	}
 }

src/Controls/src/Core/Handlers/Items/CarouselViewHandler.Windows.cs

@@ -221,6 +221,11 @@ public static void MapLoop(CarouselViewHandler handler, CarouselView carouselVie
 			handler.UpdateLoop();
 		}
 
+		static void MapItemsLayoutPropertyChanged(CarouselViewHandler handler, CarouselView view, object args)
+		{
+
+		}
+
 		internal bool InitialPositionSet { get; private set; }
 
 

src/Controls/src/Core/Handlers/Items/CarouselViewHandler.cs

@@ -1,13 +1,15 @@
 #nullable disable
+using System;
+
 namespace Microsoft.Maui.Controls.Handlers.Items
 {
 	public partial class CarouselViewHandler
 	{
-		public CarouselViewHandler() : base(Mapper)
+		public CarouselViewHandler() : base(Mapper,CommandMapper)
 		{
 
 		}
-		public CarouselViewHandler(PropertyMapper mapper = null) : base(mapper ?? Mapper)
+		public CarouselViewHandler(PropertyMapper mapper = null) : base(mapper ?? Mapper, CommandMapper)
 		{
 
 		}
@@ -23,5 +25,11 @@ public CarouselViewHandler(PropertyMapper mapper = null) : base(mapper ?? Mapper
 			[Controls.CarouselView.PositionProperty.PropertyName] = MapPosition,
 			[Controls.CarouselView.CurrentItemProperty.PropertyName] = MapCurrentItem
 		};
+
+		//TODO Make this public in .NET10
+		internal static CommandMapper<CarouselView, CarouselViewHandler> CommandMapper = new(ViewCommandMapper)
+		{
+			["ItemsLayoutProperties"] = MapItemsLayoutPropertyChanged
+		};
 	}
 }

src/Controls/src/Core/Handlers/Items/CarouselViewHandler.iOS.cs

@@ -88,5 +88,10 @@ public override Size GetDesiredSize(double widthConstraint, double heightConstra
 
 			return size;
 		}
+
+		static void MapItemsLayoutPropertyChanged(CarouselViewHandler handler, CarouselView view, object args)
+		{
+
+		}
 	}
 }

src/Controls/src/Core/Handlers/Items/ItemsViewHandler.Windows.cs

@@ -350,7 +350,6 @@ protected virtual void UpdateItemsLayout()
 			_defaultVerticalScrollVisibility = null;
 
 			UpdateItemTemplate();
-			UpdateItemsSource();
 			UpdateScrollBarVisibility();
 			UpdateEmptyView();
 		}

src/Controls/src/Core/Handlers/Items/ItemsViewHandler.cs

@@ -18,6 +18,14 @@ public ItemsViewHandler(PropertyMapper mapper = null) : base(mapper ?? ItemsView
 
 		}
 
+#if !ANDROID
+		//TODO Make this public in .NET10
+		internal ItemsViewHandler(PropertyMapper mapper = null, CommandMapper commandMapper = null) : base(mapper ?? ItemsViewMapper,commandMapper)
+		{
+
+		}
+#endif
+
 		public static PropertyMapper<TItemsView, ItemsViewHandler<TItemsView>> ItemsViewMapper = new(ViewMapper)
 		{
 			[Controls.ItemsView.ItemsSourceProperty.PropertyName] = MapItemsSource,

src/Controls/src/Core/Handlers/Items/StructuredItemsViewHandler.Android.cs

@@ -1,6 +1,7 @@
 #nullable disable
 using System;
 using System.Collections.Generic;
+using System.ComponentModel;
 using System.Text;
 using AndroidX.RecyclerView.Widget;
 
@@ -25,5 +26,15 @@ public static void MapItemsLayout(StructuredItemsViewHandler<TItemsView> handler
 
 		public static void MapItemSizingStrategy(StructuredItemsViewHandler<TItemsView> handler, StructuredItemsView itemsView)
 			=> (handler.PlatformView as IMauiRecyclerView<TItemsView>)?.UpdateAdapter();
+
+		static void MapItemsLayoutPropertyChanged(StructuredItemsViewHandler<TItemsView> handler, TItemsView view, object args)
+		{
+			if(args is not PropertyChangedEventArgs propertyChanged)
+			{
+				return;
+			}
+
+			(handler.PlatformView as IMauiRecyclerViewWithUpdates<TItemsView>)?.UpdateItemsLayoutProperties(propertyChanged);
+		}
 	}
 }

src/Controls/src/Core/Handlers/Items/StructuredItemsViewHandler.Standard.cs

@@ -24,5 +24,10 @@ public static void MapItemsLayout(StructuredItemsViewHandler<TItemsView> handler
 		public static void MapItemSizingStrategy(StructuredItemsViewHandler<TItemsView> handler, StructuredItemsView itemsView)
 		{
 		}
+
+		static void MapItemsLayoutPropertyChanged(StructuredItemsViewHandler<TItemsView> handler, TItemsView view, object args)
+		{
+
+		}
 	}
 }

src/Controls/src/Core/Handlers/Items/StructuredItemsViewHandler.Tizen.cs

@@ -38,5 +38,10 @@ public static void MapHeader(StructuredItemsViewHandler<TItemsView> handler, Str
 		{
 			(handler.PlatformView as MauiCollectionView<TItemsView>)?.UpdateAdaptor();
 		}
+
+		static void MapItemsLayoutPropertyChanged(StructuredItemsViewHandler<TItemsView> handler, TItemsView view, object args)
+		{
+			(handler.PlatformView as MauiCollectionView<TItemsView>)?.UpdateLayoutManager();
+		}
 	}
 }

src/Controls/src/Core/Handlers/Items/StructuredItemsViewHandler.Windows.cs

@@ -16,52 +16,47 @@ public partial class StructuredItemsViewHandler<TItemsView> : ItemsViewHandler<T
 	{
 		View _currentHeader;
 		View _currentFooter;
-		WeakNotifyPropertyChangedProxy _layoutPropertyChangedProxy;
-		PropertyChangedEventHandler _layoutPropertyChanged;
 		const string ListViewItemStyleKey = "DefaultListViewItemStyle";
 		const string GridViewItemStyleKey = "DefaultGridViewItemStyle";
 		static WStyle _listViewItemStyle;
 		static WStyle _gridViewItemStyle;
 
-		~StructuredItemsViewHandler() => _layoutPropertyChangedProxy?.Unsubscribe();
+		//TODO: Remove this in .NET 10
+		~StructuredItemsViewHandler() { }
 
 		protected override IItemsLayout Layout { get => ItemsView?.ItemsLayout; }
 
+		//TODO: Remove this in .NET 10
 		protected override void ConnectHandler(ListViewBase platformView)
 		{
 			base.ConnectHandler(platformView);
-
-			if (Layout is not null)
-			{
-				_layoutPropertyChanged ??= LayoutPropertyChanged;
-				_layoutPropertyChangedProxy = new WeakNotifyPropertyChangedProxy(Layout, _layoutPropertyChanged);
-			}
-			else if (_layoutPropertyChangedProxy is not null)
-			{
-				_layoutPropertyChangedProxy.Unsubscribe();
-				_layoutPropertyChangedProxy = null;
-			}
 		}
 
+		//TODO: Remove this in .NET 10
 		protected override void DisconnectHandler(ListViewBase platformView)
 		{
 			base.DisconnectHandler(platformView);
+		}
 
-			if (_layoutPropertyChangedProxy is not null)
+		void UpdateItemsLayoutProperties(object args)
+		{
+			if (args is not PropertyChangedEventArgs e)
 			{
-				_layoutPropertyChangedProxy.Unsubscribe();
-				_layoutPropertyChangedProxy = null;
+				return;
 			}
-		}
 
-		void LayoutPropertyChanged(object sender, PropertyChangedEventArgs e)
-		{
 			if (e.PropertyName == GridItemsLayout.SpanProperty.PropertyName)
+			{
 				UpdateItemsLayoutSpan();
+			}
 			else if (e.PropertyName == GridItemsLayout.HorizontalItemSpacingProperty.PropertyName || e.PropertyName == GridItemsLayout.VerticalItemSpacingProperty.PropertyName)
+			{
 				UpdateItemsLayoutItemSpacing();
+			}
 			else if (e.PropertyName == LinearItemsLayout.ItemSpacingProperty.PropertyName)
+			{
 				UpdateItemsLayoutItemSpacing();
+			}
 		}
 
 		public static void MapHeaderTemplate(StructuredItemsViewHandler<TItemsView> handler, StructuredItemsView itemsView)
@@ -79,6 +74,11 @@ public static void MapItemsLayout(StructuredItemsViewHandler<TItemsView> handler
 			handler.UpdateItemsLayout();
 		}
 
+		static void MapItemsLayoutPropertyChanged(StructuredItemsViewHandler<TItemsView> handler, TItemsView view, object args)
+		{
+			handler.UpdateItemsLayoutProperties(args);
+		}
+
 		public static void MapItemSizingStrategy(StructuredItemsViewHandler<TItemsView> handler, StructuredItemsView itemsView)
 		{
 
@@ -325,13 +325,13 @@ void UpdateItemsLayoutItemSpacing()
 
 			if (Layout is LinearItemsLayout linearItemsLayout)
 			{
-				switch (ListViewBase)
+				switch (linearItemsLayout.Orientation)
 				{
-					case FormsListView formsListView:
-						formsListView.ItemContainerStyle = GetVerticalItemContainerStyle(linearItemsLayout);
+					case ItemsLayoutOrientation.Vertical:
+						ListViewBase.ItemContainerStyle = GetVerticalItemContainerStyle(linearItemsLayout);
 						break;
-					case WListView listView:
-						listView.ItemContainerStyle = GetHorizontalItemContainerStyle(linearItemsLayout);
+					case ItemsLayoutOrientation.Horizontal:
+						ListViewBase.ItemContainerStyle = GetHorizontalItemContainerStyle(linearItemsLayout);
 						break;
 				}
 			}

src/Controls/src/Core/Handlers/Items/StructuredItemsViewHandler.cs

@@ -8,11 +8,11 @@ namespace Microsoft.Maui.Controls.Handlers.Items
 {
 	public partial class StructuredItemsViewHandler<TItemsView> where TItemsView : StructuredItemsView
 	{
-		public StructuredItemsViewHandler() : base(StructuredItemsViewMapper)
+		public StructuredItemsViewHandler() : base(StructuredItemsViewMapper, StructuredItemsViewCommandMapper)
 		{
 
 		}
-		public StructuredItemsViewHandler(PropertyMapper mapper = null) : base(mapper ?? StructuredItemsViewMapper)
+		public StructuredItemsViewHandler(PropertyMapper mapper = null) : base(mapper ?? StructuredItemsViewMapper,StructuredItemsViewCommandMapper)
 		{
 
 		}
@@ -33,5 +33,11 @@ public StructuredItemsViewHandler(PropertyMapper mapper = null) : base(mapper ??
 			[StructuredItemsView.ItemSizingStrategyProperty.PropertyName] = MapItemSizingStrategy
 		};
 
+		//TODO Make this public in .NET10
+		internal static CommandMapper<TItemsView, StructuredItemsViewHandler<TItemsView>> StructuredItemsViewCommandMapper = new(ViewCommandMapper)
+		{
+			["ItemsLayoutProperties"] = MapItemsLayoutPropertyChanged
+		};
+
 	}
 }