Red border doesn't disappear with INotifyDataErrorInfo

[vsfeedback]

This issue has been moved from a ticket on Developer Community.

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I have attached a simple project reproducing the issue.

The issue is that the red border (meaning there is an error) remains on my control even though error is cleared.

In a WPF app, I have a “MainWindow”, containing a “TestContainer” view (using a ContentControl), containing a “TestUserControl” view.

In the TestUserControlViewModel, when the OutsideString dependency property is set, I clear the error manually. But this is not taken into account and the red border remains --> NOK

If I add a button to the UI to clear the error, then it works and the red border disappears.

It looks like a bug in the framework.

Do you have any idea ?

WpfApp1.zip

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Original Comments

Feedback Bot on 3/19/2024, 07:17 PM:

(private comment, text removed)

Ann Yang [MSFT] on 3/20/2024, 00:28 AM:

(private comment, text removed)

Nicolas Géré on 3/20/2024, 03:02 AM:

(private comment, text removed)

Feedback Bot on 3/26/2024, 01:43 AM:

(private comment, text removed)

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Original Solutions

(no solutions)

[miloush]

It seems that the reason it is not cleared is that there is no longer any error to clear, i.e. while on load the red border is shown, it doesn't reflect the current validation state.

So if there is a bug, it's in the red border being visible from the beginning, not that it doesn't disappear on error clearance.

[miloush]

OK I am convinced this is a bug.

wpf/src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/Validation.cs

Lines 453 to 457 in ee1e9e4

	// try again later, perhaps giving layout a chance to create the adorner layer
	adornerSite.Dispatcher.BeginInvoke(DispatcherPriority.Loaded,
	new DispatcherOperationCallback(ShowValidationAdornerOperation),
	new object[] { targetElement, adornerSite, BooleanBoxes.Box(show) });
	}

1. code above schedules an operation to show the adorner, because adorner layer does not exist yet
2. then the adorner is to be hidden, at that point layer already exists but dispatcher did not get to run the show operation yet
3. the dispatcher runs and shows the adorner although that is an outdated instruction

The solution is to:

1. either remember the requested visibility and recheck it inside the dispatcher operation
2. or, remember the dispatcher operation and cancel it if outdated

It is slightly complicated by the fact that the above is all static methods and both solutions need to be stored per target instance.

[NicolasGereMeggitt]

Hello,

The problem has been reported more than 1 year ago now. Any chance it gets fixed soon ?

Thanks a lot

[lindexi]

@NicolasGereMeggitt I investigated this issue last night. As @miloush says, this situation seems rather complicated and is not expected to be fixed soon.