Removed Value property coercion in RadioButton

[kubaflo]

Eliminated the coercion logic that set RadioButton.Value to the instance when null, allowing Value to be explicitly set to null. Updated related unit test to reflect the new behavior.

Note

Are you waiting for the changes in this PR to be merged?
It would be very helpful if you could test the resulting artifacts from this PR and let us know in a comment if this change resolves your issue. Thank you!

Description of Change

Eliminated the coercion logic that set RadioButton.Value to the instance when null, allowing Value to be explicitly set to null. Updated related unit test to reflect the new behavior.

Issues Fixed

Fixes #32466

[dotnet-policy-service]

Hey there @@kubaflo! Thank you so much for your PR! Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[jfversluis]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[Copilot]

Pull Request Overview

This PR removes the automatic coercion of RadioButton.Value from null to the RadioButton instance itself, allowing developers to explicitly set Value to null. This fixes issue #32466 where the previous behavior prevented null values.

Key Changes:

• Removed the coerceValue callback and constructor initialization that forced Value to default to the RadioButton instance
• Updated the unit test to verify that Value can now be explicitly set to and remain null

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
src/Controls/src/Core/RadioButton/RadioButton.cs	Removed coercion logic from ValueProperty and removed constructor initialization that set Value to this
src/Controls/tests/Core.UnitTests/RadioButtonTests.cs	Updated test to verify Value can be explicitly set to null instead of being coerced to the RadioButton instance

[PureWeen]

/rebase

[PureWeen]

@asi-evin do you have any comments on this fix?

I'm curious about why you'd added this coercion in the first place and wanted to make sure we aren't missing something here.

Also @kubaflo :-)

I asked our friend copilot about this PR and it found one scenario we might want to consider (in a separate PR)

[Fact(Skip = "Known issue: RadioButtonGroupController doesn't check buttons with Value=null when SelectedValue=null. See PR #32489 validation report.")]
		public void CanSelectRadioButtonWithNullValue()
		{
			// This test proves the bug: when you have a RadioButton with Value=null
			// and set SelectedValue=null, the button should be checked (like a "Don't know" option)
			var layout = new Grid();
			layout.SetValue(RadioButtonGroup.GroupNameProperty, "test");

			var radioButtonA = new RadioButton() { Value = "A" };
			var radioButtonB = new RadioButton() { Value = "B" };
			var radioButtonNull = new RadioButton() { Value = null };  // "Don't know" option

			layout.Children.Add(radioButtonA);
			layout.Children.Add(radioButtonB);
			layout.Children.Add(radioButtonNull);

			// First, select "A"
			layout.SetValue(RadioButtonGroup.SelectedValueProperty, "A");
			Assert.True(radioButtonA.IsChecked);
			Assert.False(radioButtonB.IsChecked);
			Assert.False(radioButtonNull.IsChecked);

			// Now select the "Don't know" option by setting SelectedValue to null
			layout.SetValue(RadioButtonGroup.SelectedValueProperty, null);

			// Expected: radioButtonNull should be checked (because its Value is null)
			// Expected: radioButtonA should be unchecked
			Assert.False(radioButtonA.IsChecked, "RadioButton A should be unchecked");
			Assert.False(radioButtonB.IsChecked, "RadioButton B should remain unchecked");
			Assert.True(radioButtonNull.IsChecked, "RadioButton with Value=null should be checked when SelectedValue=null");
		}

[kubaflo]

@PureWeen yeah my man @copilot is right, and it is an interesting case. I can handle it.

[PureWeen]

/backport to release/10.0.1xx-sr1

[github-actions]

Started backporting to release/10.0.1xx-sr1 (link to workflow run)

[asi-evin]

@asi-evin do you have any comments on this fix?

I'm curious about why you'd added this coercion in the first place and wanted to make sure we aren't missing something here.

I'll be able to look at this tomorrow or even the weekend, but I took a breif look at my pull request. I didn't find the exact UI test (not unit test, I was mistaken there), but I think I recall it had something to do with multiple radio buttons in the same group all being NULL.

...Or I'm just making this all up in my head, hopefully I can find out tomorrow.