Fix Permission CTD for packaged/unpackaged apps using CameraView by ne0rrmatrix · Pull Request #3157 · CommunityToolkit/Maui

ne0rrmatrix · 2026-03-17T06:53:39Z

Description of Change

There is a bug in CameraView in sample app where it requests permission for microphone and camera in an unpackaged app. This will crash the sample app. An unpackaged app does not require permissions for either camera or microphone when not packaged.

This also fixes a bug where the method signature for a Command is incorrect which is crashing sample app.

Linked Issues

PR Checklist

Has a linked Issue, and the Issue has been approved(bug) or Championed (feature/proposal)
Has tests (if omitted, state reason in description)
Has samples (if omitted, state reason in description)
Rebased on top of main at time of PR
Changes adhere to coding standard
Documentation created or updated: https://github.com/MicrosoftDocs/CommunityToolkit/pulls

Additional information

This is another packaged/unpackaged app issue that is related to permissions. Includes a second bug that needed to be fixed to test and prevent crashes.

Updated CameraViewPage to grant permissions automatically for unpackaged apps, avoiding unnecessary prompts. Changed CreateStopCameraPreviewCommand to use Command<CancellationToken> for consistency with start command.

ne0rrmatrix · 2026-03-17T09:26:12Z

@VladislavAntonyuk can you take one more pass. I realized i excluded android,ios and mac catalyst. Fixed now.

Refactored the logic for requesting camera and microphone permissions in OnAppearing. Instead of explicitly checking for Android, iOS, or MacCatalyst, permissions are now requested on all non-Windows platforms or when the app is packaged. This makes the condition more maintainable and future-proof.

MFinkBK · 2026-05-13T07:21:24Z

We found the same issue in the PR #3140 and fixed it in a similar way. Let's see which PR is merged sooner :-)

VladislavAntonyuk · 2026-06-04T18:26:22Z

@ne0rrmatrix could you please rebase

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Pull request overview

Copilot reviewed 2 out of 3 changed files in this pull request and generated 2 comments.

Changed StopCameraPreviewCommand and its BindableProperty from ICommand to Command<CancellationToken> for consistency with StartCameraPreviewCommand. Updated documentation to reflect the new parameter requirements and usage.

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Copilot reviewed 2 out of 3 changed files in this pull request and generated 3 comments.

ne0rrmatrix · 2026-06-04T20:42:41Z

 	public static readonly BindableProperty StopCameraPreviewCommandProperty =
-		BindableProperty.CreateReadOnly(nameof(StopCameraPreviewCommand), typeof(ICommand), typeof(CameraView), null, BindingMode.OneWayToSource, defaultValueCreator: CreateStopCameraPreviewCommand).BindableProperty;
+		BindableProperty.CreateReadOnly(nameof(StopCameraPreviewCommand), typeof(Command<CancellationToken>), typeof(CameraView), null, BindingMode.OneWayToSource, defaultValueCreator: CreateStopCameraPreviewCommand).BindableProperty;


Do we want to align this with every other command or do we want to keep this as an ICommand? @VladislavAntonyuk @TheCodeTraveler

@ne0rrmatrix I don't think any change related to StopCameraPreviewCommand in this PR is needed.

The original issue #3156 has already been fixed in #3167, and the fix was to change StopCameraPreviewCommand from Command<CancellationToken> to ICommand.

The root cause of the issue was that the method CameraView.StopCameraPreview() which the StopCameraPreviewCommand calls internally has a return type void instead of a Task. This means StopCameraPreviewCommand does not need to use a CancelationToken.

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Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 4 comments.

…llation check

Copilot

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

+	static Command<CancellationToken> CreateStopCameraPreviewCommand(BindableObject bindable)
 	{
 		var cameraView = (CameraView)bindable;
-		return new Command(cameraView.StopCameraPreview);
+		return new(token => cameraView.StopCameraPreview());
 	}


 	/// <summary>
-	/// Gets the <see cref="ICommand"/> that stops the camera preview.
+	/// Gets the <see cref="Command{CancellationToken}"/> that stops the camera preview.
 	/// </summary>
-	public ICommand StopCameraPreviewCommand => (ICommand)GetValue(StopCameraPreviewCommandProperty);
+	/// <remarks>
+	/// <see cref="StopCameraPreviewCommand"/> has a <see cref="Type"/> of Command&lt;CancellationToken&gt; which requires a <see cref="CancellationToken"/> as a CommandParameter. See <see cref="Command{CancellationToken}"/> and <see cref="System.Windows.Input.ICommand.Execute(object)"/> for more information on passing a <see cref="CancellationToken"/> into <see cref="Command{T}"/> as a CommandParameter
+	/// </remarks>
+	public Command<CancellationToken> StopCameraPreviewCommand => (Command<CancellationToken>)GetValue(StopCameraPreviewCommandProperty);



zhitaop · 2026-06-24T02:13:21Z

 	{
 		var cameraView = (CameraView)bindable;
-		return new Command(cameraView.StopCameraPreview);
+		return new(token => cameraView.StopCameraPreview());


As mentioned in my previous comment, I believe this change is not necessary as the token added in the lambda function here is not used.

VladislavAntonyuk · 2026-10-28T05:12:56Z

@ne0rrmatrix is it still needed? Gerald made similar changes.

ne0rrmatrix · 2026-10-28T05:20:58Z

@ne0rrmatrix is it still needed? Gerald made similar changes.

It has been a long while since I looked at this. Looking at the fix it deals specifically with how to handle packaged vs unpackaged and there are classes that are available for packaged that were being used and are no longer being used. So this is stale now. The issue it fixes is no longer present in the toolkit. Or at least mitigated by @jfversluis. I am closing this now. It can be reopened or made fresh if it is needed in the future.

Handle permissions by packaging model; unify command types

d38cbdd

Updated CameraViewPage to grant permissions automatically for unpackaged apps, avoiding unnecessary prompts. Changed CreateStopCameraPreviewCommand to use Command<CancellationToken> for consistency with start command.

Copilot AI review requested due to automatic review settings March 17, 2026 06:53

Copilot started reviewing on behalf of ne0rrmatrix March 17, 2026 06:54

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ne0rrmatrix mentioned this pull request Mar 17, 2026

[BUG] CameraView StopCameraPreviewCommand is not working #3156

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ne0rrmatrix mentioned this pull request Mar 17, 2026

[BUG] Problems with Some CameraView StopVideoRecording on IOS #3152

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ne0rrmatrix requested a review from VladislavAntonyuk March 17, 2026 08:44

VladislavAntonyuk previously approved these changes Mar 17, 2026

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Added support for android, ios, and mac catalyst for permissions

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ne0rrmatrix dismissed VladislavAntonyuk’s stale review via 3d69286 March 17, 2026 09:25

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Comment thread samples/CommunityToolkit.Maui.Sample/Pages/Views/CameraView/CameraViewPage.xaml.cs Outdated

ne0rrmatrix added 5 commits March 17, 2026 02:50

Merge branch 'main' into FixCamerPermissionsBug

84ae49e

Merge branch 'main' into FixCamerPermissionsBug

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Merge branch 'main' into FixCamerPermissionsBug

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Merge branch 'main' into FixCamerPermissionsBug

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ne0rrmatrix requested a review from VladislavAntonyuk March 26, 2026 14:11

dotnet-policy-service Bot added stale The author has not responded in over 30 days help wanted This proposal has been approved and is ready to be implemented labels Apr 28, 2026

ne0rrmatrix added 3 commits June 4, 2026 11:52

Fix merge commit

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Fix merge error

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Fix merge again

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TheCodeTraveler removed help wanted This proposal has been approved and is ready to be implemented stale The author has not responded in over 30 days labels Jun 4, 2026

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Comment thread src/CommunityToolkit.Maui.Camera/Views/CameraView.shared.cs

Comment thread samples/CommunityToolkit.Maui.Sample/Pages/Views/CameraView/CameraViewPage.xaml.cs

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ne0rrmatrix added 2 commits June 4, 2026 13:37

Enhance StopCameraPreviewCommand to support cancellation token

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Fix camera and microphone permission requests in CameraViewPage

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ne0rrmatrix requested a review from Copilot June 4, 2026 20:43

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Simplify CreateStopCameraPreviewCommand by removing unnecessary cance…

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zhitaop reviewed Jun 24, 2026

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dotnet-policy-service Bot added stale The author has not responded in over 30 days help wanted This proposal has been approved and is ready to be implemented labels Jul 24, 2026

Merge branch 'main' into FixCamerPermissionsBug

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ne0rrmatrix closed this Oct 28, 2026

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ne0rrmatrix commented Mar 17, 2026

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