WinForms - Using Mutex to force only one instance of Form

   1: static class Program

   2:  {

   3:      ///<summary>

   4:      /// The main entry point for the application.

   5:      ///</summary>

   6:      [STAThread]

   7:      static void Main()

   8:      {

   9:          bool instanceCountOne = false;

  10:  

  11:          using (Mutex mtex = new Mutex(true, "MyRunningApp", out instanceCountOne))

  12:          {

  13:              if (instanceCountOne)

  14:              {

  15:                  Application.EnableVisualStyles();

  16:                  Application.SetCompatibleTextRenderingDefault(false);

  17:                  Application.Run(new Form1());

  18:                  mtex.ReleaseMutex();

  19:              }

  20:              else

  21:              {

  22:                  MessageBox.Show("An application instance is already running");

  23:              }

  24:          }

  25:      }

  26:  }