Push notification handler on Windows Phone 8

Question

Following this example (http://msdn.microsoft.com/en-us/library/windowsphone/develop/hh202967(v=vs.105).aspx) I have enabled my Windows Phone 8 app for push notifications. I can receive notifications and the callback method PushChannel_ShellToastNotificationReceived is called. From the example, this method opens a message box with the notification contents.

Can I therefore assume that it is safe to execute UI related operations from the thread the callback is executed in? I see that the message box is wrapped in Dispatcher.BeginInvoke(() =>, however I have no idea what thread this will be executed in, and what objects I should use from this thread.

Answer 1

PushChannel_ShellToastNotificationReceived is always called by the OS when a push notification is received while your app is running so it will execute on a non-UI thread.

Any UI related code that needs to be executed must be wrapped inside Dispatcher.BeginInvoke(Action a) otherwise you'll get an UnauthorizedAccessException exception.