[2025/04/21] Candidate - In Flight Branch (#29037)

### Description of Change

## .NET MAUI Release Notes - Inflight/Candidate

## What's Changed

### MAUI Product Fixes
* Fix CarouselView layout SR6 regressions by @albyrock87 in
#29035
* Revert "[Android] picker - focus/unfocus events (#28122)" by @PureWeen
in https://github.com/dotnet/maui/pull/1fb5164929
* [Windows] Fixed the flyout content width not being set correctly after
updating to WinUI SDK 1.7 by @Tamilarasan-Paranthaman in
#28996
* [Android] picker - focus/unfocus events by @kubaflo in
#28122
* [XC] add IRootObjectProvider by @StephaneDelcroix in
#28310
* [iOS] Fix for the File.ContentType from MediaPicker not being in valid
MIME format by @SyedAbdulAzeemSF4852 in
#28842
* [Android] Fixed the Incorrect Text Color Applied to Selected Tab in
TabbedPage by @Ahamed-Ali in #28844
* [iOS] Fix FlyoutPage does not respond to changes in the
FlyoutLayoutBehavior property by @devanathan-vaithiyanathan in
#28884
* [Android] Fixed ScalingCanvas.SetBlur not working by
@NirmalKumarYuvaraj in #28911
* [iOS] - Resolved Proper Rendering of Dynamic Header/Footer Updates in
CV2 by @prakashKannanSf3972 in #28641
* [iOS] Fixed the TargetInvocationException Occurs When Selecting
Header/Footer After Changing ItemsLayout in CV2 by @Ahamed-Ali in
#28890
* [Windows] - Fix Visual State Issue with Picker TextColor After
Navigation by @prakashKannanSf3972 in
#28746

### Dependency Updates
* [Windows] Upgrade to Windows App SDK 1.7 by @MartyIX in
#28499

### Testing
* [Testing] Feature Matrix UITest Cases for CollectionView EmptyView
Feature by @NafeelaNazhir in #28679
* Fixed Test case failure in PR 29037 - [2025/04/21] Candidate by
@HarishKumarSF4517 in #29049

**Full Changelog**:
main...inflight/candidate


For more information about inflight process check
https://github.com/dotnet/maui/wiki/Inflight-Branch-Process

Author: PureWeen

eng/Versions.props

@@ -61,7 +61,7 @@
     <MicrosoftNETWorkloadEmscriptenCurrentManifest90100TransportVersion>9.0.0</MicrosoftNETWorkloadEmscriptenCurrentManifest90100TransportVersion>
     <MicrosoftNETWorkloadEmscriptenPackageVersion>$(MicrosoftNETWorkloadEmscriptenCurrentManifest90100TransportVersion)</MicrosoftNETWorkloadEmscriptenPackageVersion>
     <!-- wasdk -->
-    <MicrosoftWindowsAppSDKPackageVersion>1.6.250228001</MicrosoftWindowsAppSDKPackageVersion>
+    <MicrosoftWindowsAppSDKPackageVersion>1.7.250401001</MicrosoftWindowsAppSDKPackageVersion>
     <MicrosoftWindowsSDKBuildToolsPackageVersion>10.0.22621.756</MicrosoftWindowsSDKBuildToolsPackageVersion>
     <MicrosoftGraphicsWin2DPackageVersion>1.2.0</MicrosoftGraphicsWin2DPackageVersion>
     <MicrosoftWindowsWebView2PackageVersion>1.0.2903.40</MicrosoftWindowsWebView2PackageVersion>

src/Controls/src/Build.Tasks/NodeILExtensions.cs

@@ -625,7 +625,8 @@ public static IEnumerable<Instruction> PushServiceProvider(this INode node, ILCo
 			//Add a SimpleValueTargetProvider and register it as IProvideValueTarget, IReferenceProvider and IProvideParentValues
 			if (createAllServices
 				|| requiredServices.Contains(module.ImportReference(context.Cache, ("Microsoft.Maui.Controls", "Microsoft.Maui.Controls.Xaml", "IProvideParentValues")), TypeRefComparer.Default)
-				|| requiredServices.Contains(module.ImportReference(context.Cache, ("Microsoft.Maui.Controls", "Microsoft.Maui.Controls.Xaml", "IReferenceProvider")), TypeRefComparer.Default))
+				|| requiredServices.Contains(module.ImportReference(context.Cache, ("Microsoft.Maui.Controls", "Microsoft.Maui.Controls.Xaml", "IReferenceProvider")), TypeRefComparer.Default)
+				|| requiredServices.Contains(module.ImportReference(context.Cache, ("Microsoft.Maui.Controls", "Microsoft.Maui.Controls.Xaml", "IRootObjectProvider")), TypeRefComparer.Default))
 			{
 				alreadyContainsProvideValueTarget = true;
 				var pushParentIl = node.PushParentObjectsArray(context).ToList();
@@ -644,9 +645,25 @@ public static IEnumerable<Instruction> PushServiceProvider(this INode node, ILCo
 					foreach (var instruction in PushNamescopes(node, context, module))
 						yield return instruction;
 
-					yield return Create(Ldc_I4_0); //don't ask
+					//rootObject
+					if (context.Root is VariableDefinition rootVariable)
+						yield return Create(Ldloc, rootVariable);
+					else if (context.Root is FieldReference rootField)
+					{
+						yield return Create(Ldarg_0);
+						yield return Create(Ldfld, rootField);
+					}
+					else
+						yield return Create(Ldnull);
+						
 					yield return Create(Newobj, module.ImportCtorReference(context.Cache,
-						("Microsoft.Maui.Controls.Xaml", "Microsoft.Maui.Controls.Xaml.Internals", "SimpleValueTargetProvider"), paramCount: 4));
+						type: ("Microsoft.Maui.Controls.Xaml", "Microsoft.Maui.Controls.Xaml.Internals", "SimpleValueTargetProvider"), 
+						parameterTypes: [
+							("mscorlib", "System", "Object[]"),
+							("mscorlib", "System", "Object"),
+							("Microsoft.Maui.Controls", "Microsoft.Maui.Controls.Internals", "INameScope[]"),
+							("mscorlib", "System", "Object"),
+						]));
 
 					//store the provider so we can register it again with a different key
 					yield return Create(Dup);
@@ -660,6 +677,12 @@ public static IEnumerable<Instruction> PushServiceProvider(this INode node, ILCo
 					yield return Create(Call, module.ImportMethodReference(context.Cache, ("mscorlib", "System", "Type"), methodName: "GetTypeFromHandle", parameterTypes: new[] { ("mscorlib", "System", "RuntimeTypeHandle") }, isStatic: true));
 					yield return Create(Ldloc, refProvider);
 					yield return Create(Callvirt, addService);
+					
+					yield return Create(Dup); //Keep the serviceProvider on the stack
+					yield return Create(Ldtoken, module.ImportReference(context.Cache, ("Microsoft.Maui.Controls", "Microsoft.Maui.Controls.Xaml", "IRootObjectProvider")));
+					yield return Create(Call, module.ImportMethodReference(context.Cache, ("mscorlib", "System", "Type"), methodName: "GetTypeFromHandle", parameterTypes: new[] { ("mscorlib", "System", "RuntimeTypeHandle") }, isStatic: true));
+					yield return Create(Ldloc, refProvider);
+					yield return Create(Callvirt, addService);
 				}
 			}
 

src/Controls/src/Build.Tasks/XamlCache.cs

@@ -3,6 +3,7 @@
 using Microsoft.Maui.Controls.XamlC;
 using Mono.Cecil;
 using Mono.Cecil.Cil;
+using Mono.Cecil.Rocks;
 
 namespace Microsoft.Maui.Controls.Build.Tasks;
 
@@ -38,8 +39,13 @@ public TypeDefinition Resolve(TypeReference typeReference) =>
 	public FieldReference GetOrAddFieldReference((ModuleDefinition module, string fieldRefKey) key, Func<(ModuleDefinition module, string fieldRefKey), FieldReference> valueFactory) =>
 		GetOrAdd(_fieldReferenceCache, key, valueFactory);
 
-	public TypeReference GetOrAddTypeReference(ModuleDefinition module, (string assemblyName, string clrNamespace, string typeName) type) =>
-		GetOrAdd(_typeReferenceCache, (module, type.ToString()), x => x.module.ImportReference(x.module.GetTypeDefinition(this, type)));
+	public TypeReference GetOrAddTypeReference(ModuleDefinition module, (string assemblyName, string clrNamespace, string typeName) type) => GetOrAdd(_typeReferenceCache, (module, type.ToString()), x =>
+	{
+		if (type.typeName.EndsWith("[]", StringComparison.InvariantCultureIgnoreCase))
+			return x.module.GetTypeDefinition(this, (type.assemblyName, type.clrNamespace, type.typeName.Substring(0, type.typeName.Length-2))).MakeArrayType();
+		else
+			return x.module.ImportReference(x.module.GetTypeDefinition(this, type));
+	});
 
 	public TypeReference GetOrAddTypeReference(ModuleDefinition module, string typeKey, Func<(ModuleDefinition module, string typeKey), TypeReference> valueFactory) =>
 		GetOrAdd(_typeReferenceCache, (module, typeKey), valueFactory);

src/Controls/src/Core/Compatibility/Handlers/FlyoutPage/iOS/PhoneFlyoutPageRenderer.cs

@@ -366,6 +366,8 @@ void HandlePropertyChanged(object sender, PropertyChangedEventArgs e)
 				UpdateBackground();
 			else if (e.PropertyName == PlatformConfiguration.iOSSpecific.FlyoutPage.ApplyShadowProperty.PropertyName)
 				UpdateApplyShadow(((FlyoutPage)Element).OnThisPlatform().GetApplyShadow());
+			else if (e.PropertyName == Microsoft.Maui.Controls.FlyoutPage.FlyoutLayoutBehaviorProperty.PropertyName) 
+				UpdateFlyoutLayoutBehaviorChanges();				
 			else if (e.PropertyName == PlatformConfiguration.iOSSpecific.Page.PrefersHomeIndicatorAutoHiddenProperty.PropertyName ||
 					 e.PropertyName == PlatformConfiguration.iOSSpecific.Page.PrefersStatusBarHiddenProperty.PropertyName)
 				UpdatePageSpecifics();
@@ -476,6 +478,25 @@ void LayoutChildren(bool animated)
 				UpdateClickOffViewFrame();
 		}
 
+		void UpdateFlyoutLayoutBehaviorChanges()
+		{
+			LayoutChildren(true);
+			if (FlyoutPage is null) 
+				return;
+            FlyoutLayoutBehavior flyoutBehavior = FlyoutPage.FlyoutLayoutBehavior;
+            bool shouldPresent = FlyoutPageController.ShouldShowSplitMode;
+            if (flyoutBehavior == FlyoutLayoutBehavior.Popover || flyoutBehavior == FlyoutLayoutBehavior.Default)
+            {
+                shouldPresent = false;
+            }
+ 
+            if (shouldPresent != FlyoutPage.IsPresented)
+            {
+                ((IElementController)Element).SetValueFromRenderer(FlyoutPage.IsPresentedProperty, shouldPresent);
+                UpdateLeftBarButton();
+            }
+		}
+
 		void PackContainers()
 		{
 			_detailController.View.BackgroundColor = new UIColor(1, 1, 1, 1);

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

@@ -32,7 +32,10 @@ public override void ConstrainTo(CGSize constraint)
 
 		public override CGSize Measure()
 		{
-			return new CGSize(_constraint.Width, _constraint.Height);
+			// Go through the measure pass even if the constraints are fixed
+			// to ensure arrange pass has the appropriate desired size in place.
+			PlatformHandler.VirtualView.Measure(_constraint.Width, _constraint.Height);
+			return _constraint;
 		}
 
 		protected override (bool, Size) NeedsContentSizeUpdate(Size currentSize)
@@ -42,7 +45,7 @@ protected override (bool, Size) NeedsContentSizeUpdate(Size currentSize)
 
 		protected override bool AttributesConsistentWithConstrainedDimension(UICollectionViewLayoutAttributes attributes)
 		{
-			return false;
+			return _constraint.IsCloseTo(attributes.Frame.Size);
 		}
 	}
 }

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

@@ -199,6 +199,9 @@ protected override string DetermineCellReuseId(NSIndexPath indexPath)
 			return base.DetermineCellReuseId(NSIndexPath.FromItemSection(itemIndex, 0));
 		}
 
+		private protected override (Type CellType, string CellTypeReuseId) DetermineTemplatedCellType()
+			=> (typeof(CarouselTemplatedCell), "maui_carousel");
+
 		protected override void RegisterViewTypes()
 		{
 			CollectionView.RegisterClassForCell(typeof(CarouselTemplatedCell), CarouselTemplatedCell.ReuseId);

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

@@ -503,9 +503,9 @@ protected virtual string DetermineCellReuseId(NSIndexPath indexPath)
 				var dataTemplate = ItemsView.ItemTemplate.SelectDataTemplate(item, ItemsView);
 
 				var cellOrientation = ItemsViewLayout.ScrollDirection == UICollectionViewScrollDirection.Vertical ? "v" : "h";
-				var cellType = ItemsViewLayout.ScrollDirection == UICollectionViewScrollDirection.Vertical ? typeof(VerticalCell) : typeof(HorizontalCell);
+				(Type cellType, var cellTypeReuseId) = DetermineTemplatedCellType();
 
-				var reuseId = $"_maui_{cellOrientation}_{dataTemplate.Id}";
+				var reuseId = $"_{cellTypeReuseId}_{cellOrientation}_{dataTemplate.Id}";
 
 				if (!_cellReuseIds.Contains(reuseId))
 				{
@@ -521,6 +521,11 @@ protected virtual string DetermineCellReuseId(NSIndexPath indexPath)
 				: VerticalDefaultCell.ReuseId;
 		}
 
+		private protected virtual (Type CellType, string CellTypeReuseId) DetermineTemplatedCellType()
+		{
+			return (ItemsViewLayout.ScrollDirection == UICollectionViewScrollDirection.Vertical ? typeof(VerticalCell) : typeof(HorizontalCell), "maui");
+		}
+
 		[Obsolete("Use DetermineCellReuseId(NSIndexPath indexPath) instead.")]
 		protected virtual string DetermineCellReuseId()
 		{

src/Controls/src/Core/Handlers/Items2/CarouselViewHandler2.iOS.cs

@@ -38,8 +38,7 @@ protected override CarouselViewController2 CreateController(CarouselView newElem
 
 		protected override UICollectionViewLayout SelectLayout()
 		{
-			bool IsHorizontal = VirtualView.ItemsLayout.Orientation == ItemsLayoutOrientation.Horizontal;
-			UICollectionViewScrollDirection scrollDirection = IsHorizontal ? UICollectionViewScrollDirection.Horizontal : UICollectionViewScrollDirection.Vertical;
+			bool isHorizontal = VirtualView.ItemsLayout.Orientation == ItemsLayoutOrientation.Horizontal;
 
 			NSCollectionLayoutDimension itemWidth = NSCollectionLayoutDimension.CreateFractionalWidth(1);
 			NSCollectionLayoutDimension itemHeight = NSCollectionLayoutDimension.CreateFractionalHeight(1);
@@ -55,7 +54,7 @@ protected override UICollectionViewLayout SelectLayout()
 					return null;
 				}
 				double sectionMargin = 0.0;
-				if (!IsHorizontal)
+				if (!isHorizontal)
 				{
 					sectionMargin = VirtualView.PeekAreaInsets.VerticalThickness / 2;
 					var newGroupHeight = environment.Container.ContentSize.Height - VirtualView.PeekAreaInsets.VerticalThickness;
@@ -81,19 +80,19 @@ protected override UICollectionViewLayout SelectLayout()
 
 				if (OperatingSystem.IsIOSVersionAtLeast(16))
 				{
-					group = IsHorizontal ? NSCollectionLayoutGroup.GetHorizontalGroup(groupSize, item, 1) :
+					group = isHorizontal ? NSCollectionLayoutGroup.GetHorizontalGroup(groupSize, item, 1) :
 										   NSCollectionLayoutGroup.GetVerticalGroup(groupSize, item, 1);
 				}
 				else
 				{
-					group = IsHorizontal ? NSCollectionLayoutGroup.CreateHorizontal(groupSize, item, 1) :
+					group = isHorizontal ? NSCollectionLayoutGroup.CreateHorizontal(groupSize, item, 1) :
 										   NSCollectionLayoutGroup.CreateVertical(groupSize, item, 1);
 				}
 
 				// Create our section layout
 				var section = NSCollectionLayoutSection.Create(group: group);
 				section.InterGroupSpacing = itemSpacing;
-				section.OrthogonalScrollingBehavior = IsHorizontal ? UICollectionLayoutSectionOrthogonalScrollingBehavior.GroupPagingCentered : UICollectionLayoutSectionOrthogonalScrollingBehavior.None;
+				section.OrthogonalScrollingBehavior = isHorizontal ? UICollectionLayoutSectionOrthogonalScrollingBehavior.GroupPagingCentered : UICollectionLayoutSectionOrthogonalScrollingBehavior.None;
 				section.VisibleItemsInvalidationHandler = (items, offset, env) =>
 				{
 					//This will allow us to SetPosition when we are scrolling the items

src/Controls/src/Core/Handlers/Items2/CollectionViewHandler2.iOS.cs

@@ -56,6 +56,8 @@ public CollectionViewHandler2(PropertyMapper mapper = null) : base(mapper ?? Map
 			[StructuredItemsView.FooterTemplateProperty.PropertyName] = MapFooterTemplate,
 			[StructuredItemsView.HeaderProperty.PropertyName] = MapHeaderTemplate,
 			[StructuredItemsView.FooterProperty.PropertyName] = MapFooterTemplate,
+			[GroupableItemsView.GroupHeaderTemplateProperty.PropertyName] = MapHeaderTemplate,
+			[GroupableItemsView.GroupFooterTemplateProperty.PropertyName] = MapFooterTemplate,
 		};
 	}
 

src/Controls/src/Core/Handlers/Items2/iOS/CarouselTemplatedCell2.cs

@@ -0,0 +1,22 @@
+#nullable disable
+using CoreGraphics;
+using Foundation;
+using Microsoft.Maui.Graphics;
+using UIKit;
+
+namespace Microsoft.Maui.Controls.Handlers.Items2
+{
+	internal sealed class CarouselTemplatedCell2 : TemplatedCell2
+	{
+		internal new const string ReuseId = "Microsoft.Maui.Controls.CarouselTemplatedCell2";
+
+		[Export("initWithFrame:")]
+		[Microsoft.Maui.Controls.Internals.Preserve(Conditional = true)]
+		public CarouselTemplatedCell2(CGRect frame) : base(frame)
+		{
+		}
+
+		private protected override Size GetMeasureConstraints(UICollectionViewLayoutAttributes preferredAttributes)
+			=> preferredAttributes.Size.ToSize();
+	}
+}

src/Controls/src/Core/Handlers/Items2/iOS/CarouselViewController2.cs

@@ -117,6 +117,9 @@ protected override string DetermineCellReuseId(NSIndexPath indexPath)
 			return base.DetermineCellReuseId(itemIndex);
 		}
 
+		private protected override (Type CellType, string CellTypeReuseId) DetermineTemplatedCellType()
+			=> (typeof(CarouselTemplatedCell2), CarouselTemplatedCell2.ReuseId);
+
 		protected override Items.IItemsViewSource CreateItemsViewSource()
 		{
 			var itemsSource = ItemsSourceFactory2.CreateForCarouselView(ItemsView.ItemsSource, this, ItemsView.Loop);
@@ -506,54 +509,49 @@ async Task UpdateInitialPosition()
 				return;
 			}
 
-			int position = carousel.Position;
-			var currentItem = carousel.CurrentItem;
-
-			if (currentItem != null)
-			{
-				// Sometimes the item could be just being removed while we navigate back to the CarouselView
-				var positionCurrentItem = ItemsSource.GetIndexForItem(currentItem).Row;
-				if (positionCurrentItem != -1)
-				{
-					position = positionCurrentItem;
-				}
-			}
-
-			var projectedPosition = NSIndexPath.FromItemSection(position, _section);
-
-			if (LoopItemsSource.Loop)
-			{
-				//We need to set the position to the correct position since we added 1 item at the beginning
-				projectedPosition = GetScrollToIndexPath(position);
-			}
-
-			var uICollectionViewScrollPosition = IsHorizontal ? UICollectionViewScrollPosition.CenteredHorizontally : UICollectionViewScrollPosition.CenteredVertically;
-
-			await Task.Delay(100).ContinueWith((t) =>
+			await Task.Delay(100).ContinueWith(_ =>
 			{
 				MainThread.BeginInvokeOnMainThread(() =>
 				{
 					if (!IsViewLoaded)
 					{
 						return;
 					}
+
 					InitialPositionSet = true;
 
 					if (ItemsSource is null || ItemsSource.ItemCount == 0)
 					{
 						return;
 					}
 
+					int position = carousel.Position;
+					var currentItem = carousel.CurrentItem;
+
+					if (currentItem != null)
+					{
+						// Sometimes the item could be just being removed while we navigate back to the CarouselView
+						var positionCurrentItem = ItemsSource.GetIndexForItem(currentItem).Row;
+						if (positionCurrentItem != -1)
+						{
+							position = positionCurrentItem;
+						}
+					}
+
+					var projectedPosition = LoopItemsSource.Loop
+						? GetScrollToIndexPath(position) // We need to set the position to the correct position since we added 1 item at the beginning
+						: NSIndexPath.FromItemSection(position, _section);
+
+					var uICollectionViewScrollPosition = IsHorizontal ? UICollectionViewScrollPosition.CenteredHorizontally : UICollectionViewScrollPosition.CenteredVertically;
+
 					CollectionView.ScrollToItem(projectedPosition, uICollectionViewScrollPosition, false);
 
 					//Set the position on VirtualView to update the CurrentItem also
 					SetPosition(position);
 
 					UpdateVisualStates();
 				});
-
 			});
-
 		}
 
 		void UpdateVisualStates()

src/Controls/src/Core/Handlers/Items2/iOS/GroupableItemsViewController2.cs

@@ -61,20 +61,14 @@ protected override void RegisterViewTypes()
 		private protected override void RegisterSupplementaryViews(UICollectionElementKindSection kind)
 		{
 			base.RegisterSupplementaryViews(kind);
-			if (IsHorizontal)
-			{
-				CollectionView.RegisterClassForSupplementaryView(typeof(HorizontalSupplementaryView2),
-					kind, HorizontalSupplementalView2ReuseId);
-				CollectionView.RegisterClassForSupplementaryView(typeof(HorizontalDefaultSupplementalView2),
-					kind, HorizontalDefaultSupplementalView2ReuseId);
-			}
-			else
-			{
-				CollectionView.RegisterClassForSupplementaryView(typeof(VerticalSupplementaryView2),
-					kind, VerticalSupplementaryView2ReuseId);
-				CollectionView.RegisterClassForSupplementaryView(typeof(VerticalDefaultSupplementalView2),
-					kind, VerticalDefaultSupplementalView2ReuseId);
-			}
+			CollectionView.RegisterClassForSupplementaryView(typeof(HorizontalSupplementaryView2),
+				kind, HorizontalSupplementalView2ReuseId);
+			CollectionView.RegisterClassForSupplementaryView(typeof(HorizontalDefaultSupplementalView2),
+				kind, HorizontalDefaultSupplementalView2ReuseId);
+			CollectionView.RegisterClassForSupplementaryView(typeof(VerticalSupplementaryView2),
+				kind, VerticalSupplementaryView2ReuseId);
+			CollectionView.RegisterClassForSupplementaryView(typeof(VerticalDefaultSupplementalView2),
+				kind, VerticalDefaultSupplementalView2ReuseId);
 		}
 
 		string DetermineViewReuseId(NSString elementKind)
@@ -133,7 +127,9 @@ void UpdateTemplatedSupplementaryView(TemplatedCell2 cell, NSString elementKind,
 
 			var bindingContext = ItemsSource.Group(indexPath);
 
+			cell.isHeaderOrFooterChanged = true;
 			cell.Bind(template, bindingContext, ItemsView);
+			cell.isHeaderOrFooterChanged = false;
 
 			// if (cell is ItemsViewCell2)
 			// {