The winform program can only open one program at a time.

[Switch] The winform program can only open one program at a time.

Ref: http://www.jb51.net/article/17747.htm

// Add the following code bool createdNew; System to the main function of the program. threading. mutex instance = new System. threading. mutex (true, "MutexName", out createdNew); if (createdNew) {Application. run (new LoginForm (); instance. releaseMutex ();} else {Application. exit () ;}// you can also write it as follows. a form can only start Form1 a = new Form1 (); bool createdNew; System. threading. mutex instance = new System. threading. mutex (true, "MutexName", out createdNew); if (createdNew) {. showDialog (); instance. releaseMutex ();} else {. close ();}