c# - Reliably detecting that another of my applications is running

Question

I have two applications, a WinForms app and a Windows Service that will both run on the same machine. I want the WinForms app to reliably detect when the service is running. I have complete control over the design and implementation of both applications.

My first thought is to use a Mutex, instantiated by the Service and detectable by the WinForms App.

Is there a better design?

Answer 1

K. Scott Allen has a good write up on using a Mutex for this purpose and issues you'll run into with the GC.

If I want to have only one instance of the application running across all sessions on the machine, I can put the named mutex into the global namespace with the prefix “Global”.

[STAThread]
static void Main() 
{
   using(Mutex mutex = new Mutex(false, "Global" + appGuid))
   {
      if(!mutex.WaitOne(0, false))
      {
         MessageBox.Show("Instance already running");
         return;
      }

      Application.Run(new Form1());
   }
}

EDIT: Changed string literal to use escaped backslash instead of @, SO syntax highlighter didn't like the verbatim string.