Camera API problem after app crashed (winrt)

Question

Dear Sirs.
I am developing windows phone runtime app (8.1) and testing it on my Nokia Limia 520 smartphone.
I work with Camera Api (CameraPreviewImageSource from Nokia.Graphics.Imaging (Nokia Imaging SDK v 1.2.151 from NuGet)). But I think this package is not important info.
Sometimes, after using camera api many times, for instance more than 30th the app crahes. The reason of app crash in my view not important too. (Of course it is important but I ask about restore phone state after the app crashes because it may happens after
the memory consumption exception for example)
I think because app crahes I don't call Dispose method for Camera Api and after I restart the app I see the green screen in the view where I use camera api to show user images from the camera. Also I see the green screen when I launch the standart app for capturing
photo.
It will fix only when I restart the phone.
I have tried to do the following things:
1) Add handler for OnSuspending event:
  private async void OnSuspending(object sender, SuspendingEventArgs e)
            var deferral = e.SuspendingOperation.GetDeferral();
            //cleanup camera resources
            await CleanupCaptureResourcesAsync();
            deferral.Complete();
2) Add handler for OnUnhandledException event:
private void OnUnhandledException(object sender, UnhandledExceptionEventArgs e)
        e.Handled = true;
        CleanupCaptureResourcesAsync().GetAwaiter().GetResult();
        Frame rootFrame = Window.Current.Content as Frame;
        if (rootFrame!=null) rootFrame.Navigate(typeof (BlankPage11), null);
CleanupCaptureResourcesAsync method:
 public async Task CleanupCaptureResourcesAsync()
            if (CameraPreviewImageSource != null)
                CameraInitialized = false;
                await CameraPreviewImageSource.StopPreviewAsync();
                CameraPreviewImageSource.Dispose();
                CameraPreviewImageSource = null;
It is works when I relaunch the app (manualy close and start it again). But when exception occurs it is not works.
Could you please help me? How can I handle an exception, or if it not possible in some ways (as I have read at https://msdn.microsoft.com/en-us/library/dn532194.aspx) is there any way to restore Camera Api after app launched again (after crash)?
Best regards,
Aleksandr Terentev

Answer 1

Thank you for your answer.
However, I think the WinDebug wouldn’t help me enough. Because apps may crash in many situations. In my view I need either app global exception mechanism for the purpose of releasing camera api by calling Dispose method when an exception
occurs or mechanism for restoring the state of the phone camera api after app has crashed.
Yes, I can save the realtime app status but it wouldn’t help. Because when you try to initialize camera api again it wouldn’t work because the app didn’t call Dispose method and didn’t release the phone camera api.
This situation is described in the MSDN article:
 “It is extremely important that you properly shut down and dispose of the MediaCapture object and related objects when your app is suspended. Failure to do so could interfere with other apps accessing the device's camera which will
result in a negative user experience for your app.”  
(https://msdn.microsoft.com/en-us/library/windows/apps/xaml/dn642092.aspx)
But when the app crashes, OnSuspending event won’t be triggered, in my view. Therefore, after this no one app can use the camera and you have to restart your phone.