How to invoke a function on parent thread in .NET?

Question

I have a .NET class library containing a class with a method that performs some lengthy operation. When a client calls this method it should perform the lengthy operation on

Answer 1

A thread cannot just execute stuff on another thread. The closest you can get is to put a delegate on a queue for the other thread to execute, but that assumes that the other thread is cooperating about this.

In a WinForms application, the main loop looks for such queued messages on each loop iteration.

If you just need to communicate the finishing of the worker thread, you can use e.g. a flag variabe. If the main thread should be able to wait for job termination, use a semaphore or condition variable (monitor).