[Windows] Fix Indicator View Causing Looping Issue with CarouselView

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

@@ -27,6 +27,7 @@ public partial class CarouselViewHandler : ItemsViewHandler<CarouselView>
 		bool _isCarouselViewReady;
 		NotifyCollectionChangedEventHandler _collectionChanged;
 		readonly WeakNotifyCollectionChangedProxy _proxy = new();
+		int _lastScrolledToPosition = -1; // tracks last position we issued ScrollTo for, to avoid re-entry
 
 		~CarouselViewHandler() => _proxy.Unsubscribe();
 
@@ -360,14 +361,9 @@ void UpdateInitialPosition()
 
 			if (ListViewBase.Items.Count > 0)
 			{
-				if (Element.Loop)
-				{
-					var item = ItemsView.CurrentItem ?? ListViewBase.Items.FirstOrDefault();
-					_loopableCollectionView.CenterMode = true;
-					ListViewBase.ScrollIntoView(item);
-					_loopableCollectionView.CenterMode = false;
-				}
-
+				// Loop centering is no longer needed here: UpdateCurrentItem and UpdatePosition
+				// now use _lastScrolledToPosition to guard against re-entry and scroll to the
+				// correct centered position programmatically, making the explicit CenterMode block redundant.
 				if (ItemsView.CurrentItem != null)
 					UpdateCurrentItem();
 				else
@@ -387,7 +383,11 @@ void UpdateCurrentItem()
 			if (currentItemPosition < 0 || currentItemPosition >= ItemCount)
 				return;
 
-			ItemsView.ScrollTo(currentItemPosition, position: ScrollToPosition.Center, animate: ItemsView.AnimateCurrentItemChanges);
+			if (ItemsView.Position != currentItemPosition && _lastScrolledToPosition != currentItemPosition)
+			{
+				_lastScrolledToPosition = currentItemPosition;
+				ItemsView.ScrollTo(currentItemPosition, position: ScrollToPosition.Center, animate: ItemsView.AnimateCurrentItemChanges);
+			}
 		}
 
 		void UpdatePosition()
@@ -400,6 +400,12 @@ void UpdatePosition()
 			if (carouselPosition < 0 || carouselPosition >= ItemCount)
 				return;
 
+			if (!ItemsView.IsDragging && !ItemsView.IsScrolling && carouselPosition != _lastScrolledToPosition)
+			{
+				_lastScrolledToPosition = carouselPosition;
+				ItemsView.ScrollTo(carouselPosition, position: ScrollToPosition.Center, animate: ItemsView.AnimateCurrentItemChanges);
+			}
+
 			SetCarouselViewCurrentItem(carouselPosition);
 		}
 
@@ -498,6 +504,12 @@ void CarouselScrolled(object sender, ItemsViewScrolledEventArgs e)
 				return;
 			}
 
+			// User scrolled to this position — reset tracker so a future programmatic scroll to same index still fires
+			if (position != _lastScrolledToPosition)
+			{
+				_lastScrolledToPosition = -1;
+			}
+
 			if (position == Element.Position)
 			{
 				return;
@@ -523,6 +535,7 @@ void OnScrollViewChanged(object sender, ScrollViewerViewChangedEventArgs e)
 
 		void OnCollectionItemsSourceChanged(object sender, NotifyCollectionChangedEventArgs e)
 		{
+			_lastScrolledToPosition = -1;
 			var carouselPosition = ItemsView.Position;
 			var currentItemPosition = GetItemPositionInCarousel(ItemsView.CurrentItem);
 			var count = (sender as IList).Count;

src/Controls/tests/TestCases.HostApp/Issues/Issue27563.cs

@@ -0,0 +1,149 @@
+using System.Collections.ObjectModel;
+
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 27563, "[Windows] CarouselView Scrolling Issue", PlatformAffected.UWP)]
+public partial class Issue27563 : ContentPage
+{
+	public Issue27563()
+	{
+		var verticalStackLayout = new VerticalStackLayout();
+
+		var carouselItems = new ObservableCollection<string>
+		{
+			"Remain View",
+			"Actual View",
+			"Percentage View",
+		};
+
+		CarouselView carousel = new CarouselView
+		{
+			ItemsSource = carouselItems,
+			AutomationId = "carouselview",
+			HeightRequest = 200,
+			ItemTemplate = new DataTemplate(() =>
+			{
+				var grid = new Grid
+				{
+					Padding = 10
+				};
+
+				var label = new Label
+				{
+					VerticalOptions = LayoutOptions.Center,
+					HorizontalOptions = LayoutOptions.Center,
+					FontSize = 18,
+				};
+				label.SetBinding(Label.TextProperty, ".");
+				label.SetBinding(Label.AutomationIdProperty, ".");
+
+				grid.Children.Add(label);
+				return grid;
+			}),
+			HorizontalOptions = LayoutOptions.Fill,
+		};
+
+		var indicatorView = new IndicatorView
+		{
+			HorizontalOptions = LayoutOptions.Center,
+			VerticalOptions = LayoutOptions.Center
+		};
+
+		carousel.IndicatorView = indicatorView;
+
+		var carouselPositionLabel = new Label
+		{
+			Text = "CarouselPos:0",
+			AutomationId = "carouselPositionLabel",
+			HorizontalOptions = LayoutOptions.Center,
+		};
+
+		var indicatorPositionLabel = new Label
+		{
+			Text = "IndicatorPos:0",
+			AutomationId = "indicatorPositionLabel",
+			HorizontalOptions = LayoutOptions.Center,
+		};
+
+		var pingLabel = new Label
+		{
+			Text = "Ping:0",
+			AutomationId = "pingLabel",
+			HorizontalOptions = LayoutOptions.Center,
+		};
+
+		var currentItemLabel = new Label
+		{
+			Text = "CurrentItem:Remain View",
+			AutomationId = "currentItemLabel",
+			HorizontalOptions = LayoutOptions.Center,
+		};
+
+		var scrollToSecondButton = new Button
+		{
+			Text = "Scroll To Second Item",
+			AutomationId = "ScrollToSecondButton",
+			Margin = new Thickness(20, 10),
+		};
+
+		scrollToSecondButton.Clicked += (sender, e) =>
+		{
+			carousel.ScrollTo(1, position: ScrollToPosition.Center, animate: false);
+		};
+
+		var positionButton = new Button
+		{
+			Text = "Change IndicatorView Position",
+			AutomationId = "PositionButton",
+			Margin = new Thickness(20, 10),
+		};
+
+		positionButton.Clicked += (sender, e) =>
+		{
+			indicatorView.Position = 2;
+		};
+
+		var pingCount = 0;
+		var pingButton = new Button
+		{
+			Text = "Ping",
+			AutomationId = "PingButton",
+			Margin = new Thickness(20, 10),
+		};
+
+		pingButton.Clicked += (sender, e) =>
+		{
+			pingCount++;
+			pingLabel.Text = $"Ping:{pingCount}";
+		};
+
+		carousel.PropertyChanged += (sender, e) =>
+		{
+			if (e.PropertyName == CarouselView.PositionProperty.PropertyName)
+				carouselPositionLabel.Text = $"CarouselPos:{carousel.Position}";
+		};
+
+		indicatorView.PropertyChanged += (sender, e) =>
+		{
+			if (e.PropertyName == IndicatorView.PositionProperty.PropertyName)
+				indicatorPositionLabel.Text = $"IndicatorPos:{indicatorView.Position}";
+		};
+
+		carousel.CurrentItemChanged += (sender, e) =>
+		{
+			currentItemLabel.Text = $"CurrentItem:{carousel.CurrentItem}";
+		};
+
+		verticalStackLayout.Children.Add(carousel);
+		verticalStackLayout.Children.Add(indicatorView);
+		verticalStackLayout.Children.Add(scrollToSecondButton);
+		verticalStackLayout.Children.Add(positionButton);
+		verticalStackLayout.Children.Add(pingButton);
+		verticalStackLayout.Children.Add(carouselPositionLabel);
+		verticalStackLayout.Children.Add(indicatorPositionLabel);
+		verticalStackLayout.Children.Add(currentItemLabel);
+		verticalStackLayout.Children.Add(pingLabel);
+
+		Content = verticalStackLayout;
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue27563.cs

@@ -0,0 +1,50 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues
+{
+	public class Issue27563 : _IssuesUITest
+	{
+		public override string Issue => "[Windows] CarouselView Scrolling Issue";
+
+		public Issue27563(TestDevice device)
+		: base(device)
+		{ }
+
+#if !WINDOWS // On Windows, TimeoutException is thrown when enabling the Loop. Refer issue: https://github.com/dotnet/maui/issues/29245
+		[Test, Order(1)]
+		[Category(UITestCategories.CarouselView)]
+		public void VerifyCarouselViewIndicatorPositionWithoutLooping()
+		{
+			App.WaitForElement("carouselview");
+			App.WaitForElement("Remain View");
+
+			App.Tap("ScrollToSecondButton");
+			App.WaitForElement("Actual View");
+
+			App.Tap("PositionButton");
+			App.WaitForElement("Percentage View");
+
+			App.Tap("PingButton");
+			App.WaitForElement("Ping:1");
+			App.Tap("ScrollToSecondButton");
+		}
+#endif
+
+#if !WINDOWS && !MACCATALYST
+		// On Catalyst, Swipe actions not supported in Appium.
+		// On Windows, TimeoutException is thrown when enabling the Loop. Refer issue: https://github.com/dotnet/maui/issues/29245
+		[Test, Order(2)]
+		[Category(UITestCategories.CarouselView)]
+		public void VerifyCarouselViewScrolling()
+		{
+			App.WaitForElement("carouselview");
+			App.SwipeRightToLeft("carouselview");
+			App.WaitForElement("Percentage View");
+			App.Tap("PositionButton");
+			VerifyScreenshot();
+		}
+#endif
+	}
+}