[Windows] Fix for ItemsSource Does Not Dynamically Set to null in CarouselView (#29660)

* [Windows] Fix for ItemsSource Does Not Dynamically Set to null in CarouselView

* Have added test case

* Updated AutomationId for better clarity and readability

* Have modified the context of the description label

* Have committed the snapshots

Author: SyedAbdulAzeemSF4852

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

@@ -68,11 +68,6 @@ protected override void DisconnectHandler(ListViewBase platformView)
 
 		protected override void UpdateItemsSource()
 		{
-			var itemsSource = ItemsView?.ItemsSource;
-
-			if (itemsSource == null)
-				return;
-
 			var itemTemplate = ItemsView?.ItemTemplate;
 
 			if (itemTemplate == null)
@@ -149,7 +144,7 @@ protected override ItemsViewScrolledEventArgs ComputeVisibleIndexes(ItemsViewScr
 		{
 			args = base.ComputeVisibleIndexes(args, orientation, advancing);
 
-			if (ItemsView.Loop)
+			if (ItemsView.Loop && ItemsView.ItemsSource is not null)
 			{
 				args.FirstVisibleItemIndex %= ItemCount;
 				args.CenterItemIndex %= ItemCount;
@@ -513,6 +508,9 @@ void CarouselScrolled(object sender, ItemsViewScrolledEventArgs e)
 
 		void OnScrollViewChanging(object sender, ScrollViewerViewChangingEventArgs e)
 		{
+			if (ItemsView.ItemsSource is null)
+				return;
+
 			ItemsView.SetIsDragging(true);
 			ItemsView.IsScrolling = true;
 		}

src/Controls/tests/TestCases.Android.Tests/snapshots/android/VerifyCarouselViewItemsSourceClearedDynamically.png

@@ -0,0 +1,63 @@
+namespace Controls.TestCases.HostApp.Issues;
+
+[Issue(IssueTracker.Github, 29472, "ItemsSource is not dynamically cleared in the CarouselView", PlatformAffected.UWP)]
+public class Issue29472 : ContentPage
+{
+	public Issue29472()
+	{
+		Label descriptionLabel = new Label
+		{
+			Text = "The test passes if the previously bound items are cleared from the view when the ItemsSource is dynamically set to null; otherwise, it fails.",
+			FontSize = 16,
+			HorizontalOptions = LayoutOptions.Center
+		};
+
+		CarouselView carouselView = new CarouselView
+		{
+			ItemsSource = new List<string> { "Item1", "Item2" },
+			Loop = false,
+			ItemTemplate = new DataTemplate(() =>
+			{
+				Label label = new Label
+				{
+					FontSize = 24,
+					BackgroundColor = Colors.LightGray,
+					Margin = new Thickness(10)
+				};
+
+				label.SetBinding(Label.TextProperty, ".");
+				return label;
+			}),
+		};
+
+		Button clearItemsSource = new Button
+		{
+			AutomationId = "ClearItemsSourceBtn",
+			Text = "Set the ItemsSource of the CarouselView to null",
+			HorizontalOptions = LayoutOptions.Center
+		};
+
+		clearItemsSource.Clicked += (s, e) =>
+		{
+			carouselView.ItemsSource = null;
+		};
+
+		Grid grid = new Grid
+		{
+			Padding = 20,
+			RowSpacing = 15,
+			RowDefinitions =
+			{
+				new RowDefinition { Height = GridLength.Auto },                      
+                new RowDefinition { Height = GridLength.Auto },                      
+                new RowDefinition { Height = GridLength.Star }, 
+            }
+		};
+
+		grid.Add(descriptionLabel, 0, 0);
+		grid.Add(clearItemsSource, 0, 1);
+		grid.Add(carouselView, 0, 2);
+
+		Content = grid;
+	}
+}

src/Controls/tests/TestCases.HostApp/Issues/Issue29472.cs

@@ -0,0 +1,23 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue29472 : _IssuesUITest
+{
+	public Issue29472(TestDevice device) : base(device)
+	{
+	}
+
+	public override string Issue => "ItemsSource is not dynamically cleared in the CarouselView";
+
+	[Test]
+	[Category(UITestCategories.CarouselView)]
+	public void VerifyCarouselViewItemsSourceClearedDynamically()
+	{
+		App.WaitForElement("ClearItemsSourceBtn");
+		App.Tap("ClearItemsSourceBtn");
+		VerifyScreenshot();
+	}
+}