Fixed - Using CollectionView.EmptyView results in an Exception on Windows (#28367)

* Fixed Using CollectionView.EmptyView results in an Exception on Windows

* Test case written and fix slightly modified

* Test case modified

* Snap added for android and iOS

* Test case modified

* snap removed

* Test case modified

* Removed curly braces

* Test case modified

Author: KarthikRajaKalaimani

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

@@ -58,6 +58,7 @@ protected override void DisconnectHandler(ListViewBase platformView)
 		{
 			VirtualView.ScrollToRequested -= ScrollToRequested;
 			CleanUpCollectionViewSource(platformView);
+			_formsEmptyView?.Handler?.DisconnectHandler();
 			base.DisconnectHandler(platformView);
 		}
 

src/Controls/tests/TestCases.HostApp/Issue28212.cs

@@ -0,0 +1,83 @@
+using System;
+using System.Collections.Generic;
+using System.Collections.ObjectModel;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 28212, "Using CollectionView.EmptyView results in an Exception on Windows", PlatformAffected.WinPhone)]
+public class Issue28212 : NavigationPage
+{
+	Issue28212_Page1 _issue28212_Page1;
+	public Issue28212()
+	{
+		_issue28212_Page1 = new Issue28212_Page1();
+		this.PushAsync(_issue28212_Page1);
+	}
+}
+
+public class Issue28212_Page1 : ContentPage
+{
+	VerticalStackLayout verticalStackLayout;
+	Issue28212_Page2 _issue28212_Page2;
+	Button button;
+	public Issue28212_Page1()
+	{
+		_issue28212_Page2 = new Issue28212_Page2();
+		button = new Button();
+		button.Text = "Click to Navigate";
+		button.AutomationId = "Button";
+		button.Clicked += Button_Clicked;
+		button.HeightRequest = 100;
+		verticalStackLayout = new VerticalStackLayout();
+		verticalStackLayout.Children.Add(button);
+		this.Content = verticalStackLayout;
+	}
+
+	private void Button_Clicked(object sender, EventArgs e)
+	{
+		Navigation.PushAsync(_issue28212_Page2);
+	}
+}
+
+public class Issue28212_Page2 : ContentPage
+{
+	public ObservableCollection<string> Items { get; } = [];
+	VerticalStackLayout verticalStackLayout;
+	Button backButton;
+	Button addButton;
+	CollectionView _collectionView;
+	Label emptyLabel;
+	public Issue28212_Page2()
+	{
+		_collectionView = new CollectionView();
+		_collectionView.ItemsSource = Items;
+		emptyLabel = new Label();
+		emptyLabel.Text = "Empty";
+		_collectionView.EmptyView = emptyLabel;
+		addButton = new Button();
+		addButton.Text = "Add";
+		addButton.Clicked += Button_Clicked;
+		backButton = new Button();
+		backButton.Text = "Back";
+		backButton.Clicked += BackButton_Clicked;
+		backButton.AutomationId = "BackButton";
+		verticalStackLayout = new VerticalStackLayout();
+		verticalStackLayout.Children.Add(addButton);
+		verticalStackLayout.Children.Add(backButton);
+		verticalStackLayout.Children.Add(_collectionView);
+		this.Content = verticalStackLayout;
+	}
+
+	private void BackButton_Clicked(object sender, EventArgs e)
+	{
+		Navigation.PopAsync();
+	}
+
+	private void Button_Clicked(object sender, EventArgs e)
+	{
+		Items.Add("Item " + (Items.Count + 1));
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue28212.cs

@@ -0,0 +1,29 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue28212 : _IssuesUITest
+{
+	public Issue28212(TestDevice testDevice) : base(testDevice)
+	{
+	}
+
+	public override string Issue => "Using CollectionView.EmptyView results in an Exception on Windows";
+
+	[Test]
+	[Category(UITestCategories.CollectionView)]
+	public void Issue28212_CollectionView()
+	{
+		App.WaitForElement("Button");
+		App.Click("Button");
+		App.WaitForElement("Add");
+		App.Click("Add");
+		App.WaitForElement("Item 1");
+		App.Click("BackButton");
+		App.WaitForElement("Button");
+		App.Click("Button");
+		App.WaitForElement("Item 1");
+	}
+}