What is the proper way to show a WinRT MessageDialog due to a caught exception?

Question

What is the proper way to show a message dialog due to a caught exception?

I originally tried

try
{
    await DoSomething();
}
catch(InvalidOperation         


        

Answer 1

Edit: After Hans' comment about other issues, I ended up solving it by creating the following class:

public static class MessageDialogDisplayer
{
    private static readonly ConcurrentQueue<MessageDialog> _dialogQueue;
    private static readonly CancellationTokenSource _cancellationTokenSource;

    static MessageDialogDisplayer()
    {
        _dialogQueue = new ConcurrentQueue<MessageDialog>();
        _cancellationTokenSource = new CancellationTokenSource();

        new Task(DisplayQueuedDialogs, _cancellationTokenSource.Token).Start();
    }

    public static void DisplayDialog(MessageDialog dialog)
    {
        _dialogQueue.Enqueue(dialog);
    }

    private static async void DisplayQueuedDialogs()
    {
        const int millisecondsBetweenDialogChecks = 500;

        while (!_cancellationTokenSource.Token.IsCancellationRequested)
        {
            MessageDialog dialogToDisplay;
            if (_dialogQueue.TryDequeue(out dialogToDisplay))
            {
                await dialogToDisplay.ShowAsync();
            }
            else
            {
                await Task.Delay(millisecondsBetweenDialogChecks);
            }
        }
    }
}

This has changed my try/catch statement to

MessageDialog errorDialog = null;
try
{
    await DoSomething();
}
catch(InvalidOperation ex)
{
    MessageDialogDisplayer.DisplayDialog(new MessageDialog(ex.Message));
}
catch(CommunicationException)
{
    MessageDialogDisplayer.DisplayDialog(new MessageDialog(StringResourceLoader.LoginError));
}

Which makes things more stable in the long run (once I convert all message dialog callers to use this instead of showAsyncing themselves) and makes the try/catch block a lot less messy (imo).