[UWP]How to debug WebView.CapturePreviewToStreamAsync() throwing "Catastrophic failure" exception?

Question

I've been using WebView.CapturePreviewToStreamAsync successfully in an UWP app for over a year.  Yesterday I received a crash report where the stack trace contained my method that calls WebView.CapturePreviewToStreamAsync.  So, I fired up VisualStudio and tried to run this code in a debug build.  Sure enough, 9 times out of 10, WebView.CapturePreviewToStreamAsync throws:

 

- $exception {"Catastrophic failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED))"} System.Exception
- Data {System.Collections.ListDictionaryInternal} System.Collections.IDictionary {System.Collections.ListDictionaryInternal}
Count 0 int
IsFixedSize false bool
IsReadOnly false bool
IsSynchronized false bool
+ Keys {System.Collections.ListDictionaryInternal.NodeKeyValueCollection} System.Collections.ICollection {System.Collections.ListDictionaryInternal.NodeKeyValueCollection}
SyncRoot {object} object
+ Values {System.Collections.ListDictionaryInternal.NodeKeyValueCollection} System.Collections.ICollection {System.Collections.ListDictionaryInternal.NodeKeyValueCollection}
_syncRoot {object} object
count 0 int
head null System.Collections.ListDictionaryInternal.DictionaryNode
version 0 int
+ Results View Expanding the Results View will enumerate the IEnumerable
HResult -2147418113 int
HelpLink null string
IPForWatsonBuckets 0x00007ffc6d88f28f System.UIntPtr
+ InnerException null System.Exception
IsTransient false bool
Message "Catastrophic failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED))" string
RemoteStackTrace null string
Source "System.Private.CoreLib" string
StackTrace "   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()" string
+ TargetSite {Void Throw()} System.Reflection.MethodBase {System.Reflection.RuntimeMethodInfo}
WatsonBuckets null object
_HResult -2147418113 int
_className null string
- _data {System.Collections.ListDictionaryInternal} System.Collections.IDictionary {System.Collections.ListDictionaryInternal}
Count 0 int
IsFixedSize false bool
IsReadOnly false bool
IsSynchronized false bool
+ Keys {System.Collections.ListDictionaryInternal.NodeKeyValueCollection} System.Collections.ICollection {System.Collections.ListDictionaryInternal.NodeKeyValueCollection}
SyncRoot {object} object
+ Values {System.Collections.ListDictionaryInternal.NodeKeyValueCollection} System.Collections.ICollection {System.Collections.ListDictionaryInternal.NodeKeyValueCollection}
_syncRoot {object} object
count 0 int
head null System.Collections.ListDictionaryInternal.DictionaryNode
version 0 int
+ Results View Expanding the Results View will enumerate the IEnumerable
_dynamicMethods null object
_exceptionMethod null System.Reflection.MethodBase
_helpURL null string
+ _innerException null System.Exception
_ipForWatsonBuckets 0x00007ffc6d88f28f System.UIntPtr
_message "Catastrophic failure (Exception from HRESULT: 0x8000FFFF (E_UNEXPECTED))" string
_remoteStackIndex 0 int
_remoteStackTraceString null string
_source "System.Private.CoreLib" string
+ _stackTrace {sbyte[48]} object {sbyte[]}
_stackTraceString null string
_watsonBuckets null object
_xcode -532462766 int
_xptrs 0x0000000000000000 System.IntPtr
+ Static members

However, my Debug.Writeline output shows that I'm on the main thread and the WebView size is well below the hazardous thresholds:

Application output:

 webView.Size=[60,607] IsOnMainThread=[True]

And the stack trace is equally unhelpful:

  

System.Private.CoreLib.dll!System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw() Unknown
System.Private.CoreLib.dll!System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(System.Threading.Tasks.Task task) Unknown
> MyClass.NavigationCompleteB(Windows.UI.Xaml.Controls.WebView webView, Windows.UI.Xaml.Controls.WebViewNavigationCompletedEventArgs args) Line 113 C#

Here is the method where the exception is triggered:

private async void NavigationCompleteB(Windows.UI.Xaml.Controls.WebView webView, WebViewNavigationCompletedEventArgs args)

{

    var ms = new InMemoryRandomAccessStream();
    System.Diagnostics.Debug.WriteLine("webView.Size=[" + webView.Width + "," + webView.Height + "] IsOnMainThread=["+CoreWindow.GetForCurrentThread().Dispatcher.HasThreadAccess+"]");
    await webView.CapturePreviewToStreamAsync(ms);

   // do more stuff here      

}

With so little information, how do I debug this?

Answer 1

Hi,

I test your code in my side. But I could not reproduce your issue.

I'm using the code like this:

            Debug.WriteLine("webView1_NavigationCompleted");
            var ms = new InMemoryRandomAccessStream();
            Debug.WriteLine("webView.Size=[" + webView1.Width + "," + webView1.Height + "] IsOnMainThread=[" + CoreWindow.GetForCurrentThread().Dispatcher.HasThreadAccess + "]");

            await webView1.CapturePreviewToStreamAsync(ms);

            Debug.WriteLine("test");

and the output here:

webView1_NavigationCompleted
webView.Size=[NaN,NaN] IsOnMainThread=[True]
test

So you could see that the function works well in my side and there is no exception about WebView.CapturePreviewToStreamAsync(). I'm running the app which targeting build 1903 on a device with system 1903.

I need some other information about your issue. What's the target version of your app? What's the version of your device?  Is this error happens to all web links or it just happen to a specific link? Have you test on other devices to see if this issue happens? 

Best regards,

Roy

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Answer 2

Roy -

Thank you for responding.  I finally had some free time to put together a sample project for you.  You can find a GitHub repo for a sample VisualStudio solution that demonstrates this issue:

  github.com/baskren/Forms9Patch/tree/CapturePreviewToStreamAsyncFail

It is built targeting Windows 10, version 1903 (10.0 build 18362) and I'm testing it on Windows 10 Home, version 10.0.18362.

Answer 3

FWIW, I tried to add the information from VisualStudio's About screen but this forum will not allow me to post it saying there is an link or image included.

Answer 4

And yes, I have tried testing of three different Windows 10 devices and all three throw this error.

Answer 5

Roy -

I should have mentioned that you want to run the Forms9PatchDemo.Source.UWP project to see the catastrophic failure exception.

- Ben

Answer 6

Hi,

First, I'm sorry to say that I could not run your sample on my side. I checked the code in your sample. I found that you are using this API in HtmlToPngService in the native UWP app. So you are trying to put the UWP app as a dependency of the Xamarin app, right? Since I can't run your demo so I can't debug the app. 

My suggestion is that create a blank UWP app first, then test the API in the native APP first. If this works correctly, then you could create a new Xamarin app to test. I suspect this is related to Xamarin.

Anyway, you could also ask about this in the Xamarin's official forum because this issue is more related to Xamarin.

Best regards,

Roy

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