c# - How to allow for multiple popups at once in WinRT?

Question

If you call the ShowAsync command on a MessageDialog object when another MessageDialog object has already been displayed to the user but not dismissed (i.e. you show a popup when another one is already up), an UnauthorizedAccessException is thrown. This can make things difficult when you have multiple threads attempting to alert the user at the same time.

My current (stopgap) solution is merely to surround the ShowAsync call with a try/catch block and swallow the exception. This undesirably leads to the user missing out on subsequent notifications. The only other way around this that I can think of is to manually implement some sort of popup queue. This seems like an inordinate amount of work, however, considering other frameworks (like Windows Phone) do not have this issue and will merely display the popups one after another as the user dismisses them.

Is there another way to solve this problem?

Answer 1

You can easy do it with this extension method:

public static class MessageDialogShower
{
    private static SemaphoreSlim _semaphore;

    static MessageDialogShower()
    {
        _semaphore = new SemaphoreSlim(1);
    }

    public static async Task<IUICommand> ShowDialogSafely(this MessageDialog dialog)
    {
        await _semaphore.WaitAsync();
        var result = await dialog.ShowAsync();
        _semaphore.Release();
        return result;
    }
}