BackgroundTaskBuilder.Register() throws System.ArgumentException "Value does not fall within..."

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BackgroundTaskBuilder.Register() throws System.ArgumentException "Value does not fall within..."

Hong 1,436

I copied the following code from a Microsoft official document.

BackgroundAccessStatus status = await BackgroundExecutionManager.RequestAccessAsync();  
  
// Otherwise request access  
BackgroundAccessStatus status = await BackgroundExecutionManager.RequestAccessAsync();  
  
// Create the background task  
BackgroundTaskBuilder builder = new BackgroundTaskBuilder()  
{  
    Name = Utility.sOpenImageFileTask,  
};  
  
// Assign the toast action trigger  
builder.SetTrigger(new ToastNotificationActionTrigger());  
  
// And register the task  
BackgroundTaskRegistration registration = builder.Register();

It worked for a while. I suddenly started to see the following exception thrown by builder.Register().

System.ArgumentException Value does not fall within the expected range.
Stack Trace: at System.Runtime.InteropServices.McgMarshal.ThrowOnExternalCallFailed(Int32, RuntimeTypeHandle) + 0x21
at __Interop.ComCallHelpers.Call(__ComObject, RuntimeTypeHandle, Int32, Void*) + 0xbe
at __Interop.ForwardComStubs.Stub_3TThis, TResult + 0x37
at Windows.ApplicationModel.Background.BackgroundTaskBuilder.Register() + 0x18

Could anyone offer a tip on the possible causes of this exception?

Yan Gu - MSFT 2,676 Reputation points

2021-02-03T03:10:06.323+00:00

@Hong I have tested the code in the linked document and test the official sample, but I didn’t reproduce the System.ArgumentException. Could you please provide us a minimal sample by OneDrive or GitHub for testing?
Hong 1,436 Reputation points

2021-02-03T20:45:33.523+00:00

@Yan Gu - MSFT I have finally found the culprit after spending hours on it.
Per your suggestion, I created a simple project to try to reproduce this, but the exception was not thrown. Eventually, I realized that I added the feature of multi-instance recently. This exception started to happen after it. Now, the simple project can reproduce the exception consistently after adding the multi-instance support.

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Yan Gu - MSFT 2,676 Reputation points

2021-02-03T03:10:06.323+00:00

@Hong I have tested the code in the linked document and test the official sample, but I didn’t reproduce the System.ArgumentException. Could you please provide us a minimal sample by OneDrive or GitHub for testing?
Hong 1,436 Reputation points

2021-02-03T20:45:33.523+00:00

@Yan Gu - MSFT I have finally found the culprit after spending hours on it.
Per your suggestion, I created a simple project to try to reproduce this, but the exception was not thrown. Eventually, I realized that I added the feature of multi-instance recently. This exception started to happen after it. Now, the simple project can reproduce the exception consistently after adding the multi-instance support.

Answer 1

Yan Gu - MSFT 2,676

Hello,

Welcome to Microsoft Q&A.

The System.ArgumentException is reproduced when I add the multiple-instance support. And I also find the location of the exception.

You could refer to Background tasks and multi-instancing part of the Create a multi-instance Universal Windows App, and get the information that out-of-process background tasks support multi-instancing and in-process background tasks do not support multi-instancing.

In my side, when I register an in-process background task, the System.ArgumentException is thrown. When I register an out-of-process background task instead of the in-process background task, the app could run successfully.

Based on the code provided by you, it should be an in-process background task because BackgroundTaskBuilder.TaskEntryPoint Property is not set for the BackgroundTaskBuilder instance. You could try to replace your in-process background task with an out-of-process background task.

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Hong 1,436

Thank you for the clarification.
The toaster can invoke the out-of-process background task. The problem that I need the UI thread to call Launcher.LaunchFileAsync(). I tried the following

BackgroundTaskRegistration registration = taskBuilder.Register();
registration.Completed += new BackgroundTaskCompletedEventHandler(OnCompleted);

private async void OnCompleted(IBackgroundTaskRegistration task, BackgroundTaskCompletedEventArgs args)
{
    await Dispatcher.RunAsync(CoreDispatcherPriority.Normal,
        () =>
        {
            await Launcher.LaunchFileAsync(sFilePaht);
        });
}

OnCompleted is never called. Do you know why?

Yan Gu - MSFT 2,676 Reputation points

2021-02-04T05:47:58.337+00:00

@Hong I add a Completed event in my side, and the event could be called. I can’t check what is the possible reason for your scenario. Could you please tell me what you have done in the background task? It is better to provide us a simple sample by OneDrive or GitHub for me to checking the problem.
Hong 1,436 Reputation points

2021-02-04T16:13:24.683+00:00

Thanks a lot for looking into this.

I have found that OnCompleted is called after ExecutableOrStartPageRequired is unchecked.

I have another issue: Window.Current is null in OnCompleted despite the app window is visible. I will create my own in-app toaster to deal with this, so I am all set.

Thank you again for all the help.

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BackgroundTaskBuilder.Register() throws System.ArgumentException "Value does not fall within..."

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