C# Signature:

[DllImport("user32.dll")]
static extern bool IsIconic(IntPtr hWnd);

VB Signature:

Private Declare Function IsIconic Lib "user32" (ByVal hwnd As IntPtr) As Long

User-Defined Types:

None.

Notes:

The hWnd parameter can be obtained by the Handle property of a Form, or by

MainWindowHandle on a Process.

Tips & Tricks:

Please add some!

Sample Code:

      // Want only one instance of an application?

      [DllImport("User32.Dll")]
      private static extern bool SetForegroundWindow(IntPtr hWnd);
      [DllImport("User32.Dll")]
      private static extern bool ShowWindowAsync(IntPtr hWnd, int nCmdShow);
      [DllImport("User32.Dll")]
      private static extern bool IsIconic(IntPtr hWnd);


      private const int SW_RESTORE = 9;

      /// <summary>
      /// Main entry point for the application.
      /// </summary>
      [STAThread]
      static int
      Main
    (
      string[] arguments
    )
    {
      // Check for running instance

      Process thisProcess = Process.GetCurrentProcess();
      Process[] processes = Process.GetProcessesByName(thisProcess.ProcessName);

      if (processes.Length > 1)
        {
          // One is us (which will end); the other we activate

          int index = 0;
          if (processes[index].Id == thisProcess.Id)
        index = 1;

          IntPtr hWnd = processes[index].MainWindowHandle;

          if (IsIconic(hWnd))
        ShowWindowAsync(hWnd, SW_RESTORE);

          SetForegroundWindow(hWnd);

          // Exit
          return 0;
        }


       // Normal startup code continues here...

     }

Alternative Managed API:

Do you know one? Please contribute it!