July 28, 2014
Occurs when an exception that is raised by Windows Phone is not handled.
Assembly: System.Windows (in System.Windows.dll)
XMLNS for XAML: Not mapped to an xmlns.
By default, Windows Phone will detect and process unhandled exceptions that are raised from any part of the Windows Phone application. If you would prefer to perform unhandled exception detection and processing, you can handle the event, which is raised by Application for each thrown exception that is unhandled by application code.
The event handler is passed a ApplicationUnhandledExceptionEventArgs object, which stores a reference to the unhandled exception in its ExceptionObject property. You can use this information to determine whether an exception is recoverable or not.
When you detect and process an unhandled exception and you do not want Windows Phone to continue processing it, you have to set the Handled property to true. If you leave the Handled property set to false when exiting the handler, the unmanaged exception handling as registered for the onError event takes place for the unhandled exception. An onError handler can also be handled by managed code, if you marshal the handler.
The Windows Phone application project templates included with Windows Phone SDK provide an implementation of the event handler.