Is there any way to catch the crashed form and reopen it again.
public static void Dispatcher_UnhandledException(object sender, System.Windows.Threading.DispatcherUnhandledExceptionEventArgs e)
{
}
Setting e.Handler to true should prevent the app from shutting down. You will then have to write some code to bring the window up again. There is no "reopen the crashed form" switch I am afraid. There is not even any notion of a "crashed form" as far as the event handler is concerned.
Please also note that keeping an application running like this will leave it in an undefined state. What you really should do is to catch the exception where it occurs and then use the Dispatcher_UnhandledException event handler as a last resort for logging any unhandled exception, perhaps displaying a user friendly message and finally shutting the application down.