Check current application running or not C# WPF

const string appGuid = "Sample-d693gba6e9d1";  //Unique App Id

            bool result;

            System.Threading.Mutex mutex = new System.Threading.Mutex(true, appGuid, out result);

            if (!result)

            {

                MessageBox.Show("Another instance is already running.  It may be loading.");

                return;

            }

            GC.KeepAlive(mutex);