Try/Catch and threading

Well in general, you've no idea where the originating thread will be by the time the exception is thrown in the new thread - why would it be waiting around for the thread to throw an exception?

Think of the stacks involved - when an exception is thrown, it goes up the stack until it reaches an appropriate catch block. The new thread has a completely separate stack to the creating thread, so it'll never reach the catch block in the creating thread's stack.

EDIT: Of course, you could design your system so that the creating thread did wait for other things to happen - a bit like the message loop in a Windows Forms application. The new thread could then catch the exception and send a message to the creating thread, which could then deal with the exception. That isn't the normal setup though - you have to do it all explicitly.

The running thread will not be caught in your try/catch statement because it is running in another thread. Try/Catch only works for the current thread. What you need to do is have try/catch in the function being run by the thread, and have some way of managing what happens when that crash occurs.

You might want to use an EventGeneratingThread wrapper - this will let you catch and deal with exceptions thrown in threads from the process that spawned them.