Occurs when a thread is about to shut down. When the main thread for an application is about to be shut down, this event is raised first, followed by an Application.ApplicationExit event.
You must attach the event handlers to the Application.ThreadExit event to perform any unhandled, required tasks before the thread stops running. Close files opened by this thread, or dispose of objects that the garbage collector did not reclaim.
Because this is a static event, you must detach your event handlers when your application is disposed, or memory leaks will result.