Question

I’m running an asynchronous web request on Windows Phone 7 and I want the user to be able to cancel the request when it takes too long. I show a message box by calling:

IAsyncResult result = Guide.BeginShowMessageBox("Synchronize", "Synchronizing with MyWebsite.com...", new string[] { "Cancel" }, 0, MessageBoxIcon.None, OnEndDialog, null);

In the OnEndDialog callback I can cancel the request, which works fine.

But when the request is finished I want to close the message box from my code. Unfortunately, when I call

Guide.EndShowMessageBox(result);

from my code (yes, I use dispatcher.BeginInvoke to run the call on the UI thread), it turns out to be a blocking call and the dialog is still waiting for the user to press the Cancel button.

Is there any way to close the message box from code?

Answer 1

I guess it is not possible to close the Guide message box from code.

I solved the problem by using the MessagePrompt control from the Coding4Fun Windows Phone Toolkit. You can call OnCompleted(…) to close the message box.

I added a Dismiss method to the base class (UserPrompt) which can be called from a background thread:

    public void Dismiss(PopUpResult result)
    {
        // Dismiss can be called from any thread. Make sure to execute on UI thread:
        Dispatcher dispatcher = Deployment.Current.Dispatcher;
        if (dispatcher.CheckAccess())
        {
            OnCompleted(new PopUpEventArgs<string, PopUpResult> { PopUpResult = result });
        }
        else
        {
            dispatcher.BeginInvoke((Action)(() => { Dismiss(result); }));
        }
    }