C # exit several methods

1. this. close (); only closes the current window. If it is not the main form, it cannot exit the program. In addition, if there is a managed thread (not the main thread), it cannot exit cleanly;

2. Application. Exit (); force all messages to stop and exit all forms. However, if there is a managed thread (not the main thread), it cannot exit cleanly;

3. Application. exitthread (); force stop all messages on the calling thread, which also faces the problem that other threads cannot exit correctly;

4. system. environment. Exit (0); this is the most thorough exit method. No matter what thread is forced to exit, the program ends very cleanly.