how to open only one window in c# winform

Question

I write a c# windorm application and generate a install file, when I finish the installation, every time I double click the shortcut in desktop, it will open a new window, does anyone can tell me how could I just open the original window when I double click the shortcut in desktop?

possible duplicate of [this](http://stackoverflow.com/questions/6486195/ensuring-only-one-application-instance) which is a duplicate of [What is the correct way to create a single instance application?](http://stackoverflow.com/questions/19147/what-is-the-correct-way-to-create-a-single-instance-application) — Pierre-Luc Pineault, Apr 28 '14 at 05:33

score 3 · Accepted Answer · edited Oct 13 '15 at 22:46

I prefer a mutex solution similar to the following. As this way it re-focuses on the app if it is already loaded

using System.Threading;

[DllImport("user32.dll")]
[return: MarshalAs(UnmanagedType.Bool)]
static extern bool SetForegroundWindow(IntPtr hWnd);

/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
   bool createdNew = true;
   using (Mutex mutex = new Mutex(true, "MyApplicationName", out createdNew))
   {
      if (createdNew)
      {
         Application.EnableVisualStyles();
         Application.SetCompatibleTextRenderingDefault(false);
         Application.Run(new MainForm());
      }
      else
      {
         Process current = Process.GetCurrentProcess();
         foreach (Process process in Process.GetProcessesByName(current.ProcessName))
         {
            if (process.Id != current.Id)
            {
               SetForegroundWindow(process.MainWindowHandle);
               break;
            }
         }
      }
   }
}

It gives focus to your application window if it is already running.

how to open only one window in c# winform

1 Answers1