[Issue-Resolver] Fix #33264 - RadioButtonGroup not working with Collection View

src/Controls/src/Core/RadioButton/RadioButtonGroupController.cs

@@ -24,6 +24,8 @@ public RadioButtonGroupController(Maui.ILayout layout)
 			_layout = (Element)layout;
 			_layout.ChildAdded += ChildAdded;
 			_layout.ChildRemoved += ChildRemoved;
+			_layout.DescendantAdded += DescendantAdded;
+			_layout.DescendantRemoved += DescendantRemoved;
 
 			if (!string.IsNullOrEmpty(_groupName))
 			{
@@ -97,6 +99,30 @@ void ChildRemoved(object sender, ElementEventArgs e)
 			}
 		}
 
+		void DescendantAdded(object sender, ElementEventArgs e)
+		{
+			if (string.IsNullOrEmpty(_groupName) || _layout == null)
+			{
+				return;
+			}
+
+			if (e.Element is RadioButton radioButton)
+			{
+				AddRadioButton(radioButton);
+			}
+		}
+
+		void DescendantRemoved(object sender, ElementEventArgs e)
+		{
+			if (e.Element is RadioButton radioButton)
+			{
+				if (groupControllers.TryGetValue(radioButton, out _))
+				{
+					groupControllers.Remove(radioButton);
+				}
+			}
+		}
+
 		internal void HandleRadioButtonValueChanged(RadioButton radioButton)
 		{
 			if (radioButton?.GroupName != _groupName)

src/Controls/tests/Core.UnitTests/RadioButtonTests.cs

@@ -319,5 +319,95 @@ public void ValuePropertyCanBeSetToNull()
 
 			Assert.Null(radioButton.Value);
 		}
+
+		[Fact]
+		public void RadioButtonGroupWorksWithDynamicallyAddedDescendants()
+		{
+			// Simulates CollectionView scenario where RadioButtons are added as descendants
+			// rather than direct children (they're inside ItemTemplate)
+			var layout = new StackLayout();
+			var groupName = "choices";
+
+			// Set up RadioButtonGroup on parent layout
+			layout.SetValue(RadioButtonGroup.GroupNameProperty, groupName);
+			layout.SetValue(RadioButtonGroup.SelectedValueProperty, null);
+
+			// Create a container that simulates CollectionView item container
+			var itemContainer = new StackLayout();
+			layout.Children.Add(itemContainer);
+
+			// Create RadioButtons and add them to the nested container
+			// This triggers DescendantAdded events (like CollectionView does)
+			var radioButton1 = new RadioButton() { Value = "Choice 1" };
+			var radioButton2 = new RadioButton() { Value = "Choice 2" };
+			var radioButton3 = new RadioButton() { Value = "Choice 3" };
+
+			itemContainer.Children.Add(radioButton1);
+			itemContainer.Children.Add(radioButton2);
+			itemContainer.Children.Add(radioButton3);
+
+			// Verify RadioButtons received the group name from ancestor
+			Assert.Equal(groupName, radioButton1.GroupName);
+			Assert.Equal(groupName, radioButton2.GroupName);
+			Assert.Equal(groupName, radioButton3.GroupName);
+
+			// Verify SelectedValue is initially null
+			Assert.Null(layout.GetValue(RadioButtonGroup.SelectedValueProperty));
+
+			// Check a RadioButton
+			radioButton2.IsChecked = true;
+
+			// Verify SelectedValue binding is updated
+			Assert.Equal("Choice 2", layout.GetValue(RadioButtonGroup.SelectedValueProperty));
+
+			// Check another RadioButton
+			radioButton3.IsChecked = true;
+
+			// Verify SelectedValue binding updates again
+			Assert.Equal("Choice 3", layout.GetValue(RadioButtonGroup.SelectedValueProperty));
+
+			// Verify only one RadioButton is checked
+			Assert.False(radioButton1.IsChecked);
+			Assert.False(radioButton2.IsChecked);
+			Assert.True(radioButton3.IsChecked);
+		}
+
+		[Fact]
+		public void RadioButtonGroupSelectedValueBindingWorksWithNestedDescendants()
+		{
+			// Tests that setting SelectedValue on the group selects the correct descendant RadioButton
+			var layout = new StackLayout();
+			var groupName = "choices";
+
+			layout.SetValue(RadioButtonGroup.GroupNameProperty, groupName);
+
+			// Nested container simulating CollectionView
+			var itemContainer = new StackLayout();
+			layout.Children.Add(itemContainer);
+
+			var radioButton1 = new RadioButton() { Value = "Choice 1" };
+			var radioButton2 = new RadioButton() { Value = "Choice 2" };
+			var radioButton3 = new RadioButton() { Value = "Choice 3" };
+
+			itemContainer.Children.Add(radioButton1);
+			itemContainer.Children.Add(radioButton2);
+			itemContainer.Children.Add(radioButton3);
+
+			// Set SelectedValue from the group (simulates binding update)
+			layout.SetValue(RadioButtonGroup.SelectedValueProperty, "Choice 2");
+
+			// Verify the correct RadioButton is checked
+			Assert.False(radioButton1.IsChecked);
+			Assert.True(radioButton2.IsChecked);
+			Assert.False(radioButton3.IsChecked);
+
+			// Change SelectedValue
+			layout.SetValue(RadioButtonGroup.SelectedValueProperty, "Choice 3");
+
+			// Verify selection updates
+			Assert.False(radioButton1.IsChecked);
+			Assert.False(radioButton2.IsChecked);
+			Assert.True(radioButton3.IsChecked);
+		}
 	}
 }

src/Controls/tests/TestCases.HostApp/Issues/Issue33264.xaml

@@ -0,0 +1,23 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="Maui.Controls.Sample.Issues.Issue33264"
+             Title="Issue 33264">
+
+    <StackLayout Padding="20" Spacing="10" RadioButtonGroup.GroupName="choices" RadioButtonGroup.SelectedValue="{Binding SelectedValue}">
+        <Label Text="RadioButtonGroup not working with CollectionView" FontSize="18" FontAttributes="Bold"/>
+
+        <Label Text="Select an option below:" FontSize="14"/>
+
+        <CollectionView ItemsSource="{Binding Choices}" AutomationId="ChoicesCollectionView">
+            <CollectionView.ItemTemplate>
+                <DataTemplate>
+                    <RadioButton Content="{Binding}" Value="{Binding}" GroupName="choices" AutomationId="{Binding}"/>
+                </DataTemplate>
+            </CollectionView.ItemTemplate>
+        </CollectionView>
+
+        <Label Text="Selected value:" FontSize="14" FontAttributes="Bold"/>
+        <Label Text="{Binding SelectedValueDisplay}" FontSize="16" AutomationId="SelectedValueLabel"/>
+    </StackLayout>
+</ContentPage>

src/Controls/tests/TestCases.HostApp/Issues/Issue33264.xaml.cs

@@ -0,0 +1,68 @@
+using System.Collections.ObjectModel;
+using System.ComponentModel;
+using System.Runtime.CompilerServices;
+
+namespace Maui.Controls.Sample.Issues;
+
+[Issue(IssueTracker.Github, 33264, "RadioButtonGroup not working with CollectionView", PlatformAffected.All)]
+public partial class Issue33264 : ContentPage
+{
+	public Issue33264()
+	{
+		InitializeComponent();
+		BindingContext = new Issue33264ViewModel();
+	}
+
+	protected override void OnAppearing()
+	{
+		base.OnAppearing();
+		Dispatcher.DispatchDelayed(TimeSpan.FromMilliseconds(500), () =>
+		{
+			CaptureState("OnAppearing");
+		});
+	}
+
+	private void CaptureState(string context)
+	{
+		var vm = BindingContext as Issue33264ViewModel;
+		Console.WriteLine($"=== STATE CAPTURE: {context} ===");
+		Console.WriteLine($"SelectedValue: {vm?.SelectedValue ?? "null"}");
+		Console.WriteLine("=== END STATE CAPTURE ===");
+	}
+}
+
+public class Issue33264ViewModel : INotifyPropertyChanged
+{
+	private string _selectedValue;
+
+	public ObservableCollection<string> Choices { get; } = new ObservableCollection<string>
+	{
+		"Choice 1",
+		"Choice 2",
+		"Choice 3"
+	};
+
+	public string SelectedValue
+	{
+		get => _selectedValue;
+		set
+		{
+			if (_selectedValue != value)
+			{
+				Console.WriteLine($"=== BINDING UPDATE: SelectedValue changing from '{_selectedValue}' to '{value}' ===");
+				_selectedValue = value;
+				OnPropertyChanged();
+				OnPropertyChanged(nameof(SelectedValueDisplay));
+			}
+		}
+	}
+
+	public string SelectedValueDisplay => string.IsNullOrEmpty(SelectedValue) ? "None" : SelectedValue;
+
+	public event PropertyChangedEventHandler PropertyChanged;
+
+	protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
+	{
+		PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+	}
+}

src/Controls/tests/TestCases.Shared.Tests/Tests/Issues/Issue33264.cs

@@ -0,0 +1,49 @@
+using NUnit.Framework;
+using UITest.Appium;
+using UITest.Core;
+
+namespace Microsoft.Maui.TestCases.Tests.Issues;
+
+public class Issue33264 : _IssuesUITest
+{
+	public override string Issue => "RadioButtonGroup not working with CollectionView";
+
+	public Issue33264(TestDevice device) : base(device) { }
+
+	[Test]
+	[Category(UITestCategories.RadioButton)]
+	public void RadioButtonGroupBindingWorksInsideCollectionView()
+	{
+		// Wait for all elements to load
+		App.WaitForElement("ChoicesCollectionView");
+		App.WaitForElement("Choice 2");
+		App.WaitForElement("SelectedValueLabel");
+
+		// Initially, SelectedValue should show "None"
+		var initialValue = App.FindElement("SelectedValueLabel").GetText();
+		Console.WriteLine($"Initial SelectedValue: '{initialValue}'");
+		Assert.That(initialValue, Is.EqualTo("None"), "Initial value should be 'None'");
+
+		// Tap "Choice 2" radio button
+		App.Tap("Choice 2");
+
+		// Wait for binding update by polling the label text
+		App.WaitForTextToBePresentInElement("SelectedValueLabel", "Choice 2");
+
+		// Verify SelectedValue is updated
+		var selectedValue = App.FindElement("SelectedValueLabel").GetText();
+		Console.WriteLine($"After tapping 'Choice 2', SelectedValue: '{selectedValue}'");
+		Assert.That(selectedValue, Is.EqualTo("Choice 2"), "SelectedValue should be updated via binding when RadioButton is checked");
+
+		// Tap "Choice 3" radio button
+		App.Tap("Choice 3");
+
+		// Wait for binding update by polling the label text
+		App.WaitForTextToBePresentInElement("SelectedValueLabel", "Choice 3");
+
+		// Verify SelectedValue is updated again
+		selectedValue = App.FindElement("SelectedValueLabel").GetText();
+		Console.WriteLine($"After tapping 'Choice 3', SelectedValue: '{selectedValue}'");
+		Assert.That(selectedValue, Is.EqualTo("Choice 3"), "SelectedValue should be updated when different RadioButton is checked");
+	}
+}