GetActiveWindow will return the top-level window that is associated with the input focus. GetFocus will return the handle of the window that has the input focus. This article might help: http://www.microsoft.com/msj/0397/Win32/Win320397.aspx
Not sure it works, but you can try that : IntPtr handle = Process.GetCurrentProcess().MainWindowHandle;
If you are targeting .NET 4.0 you can make use of the new EnsureHandle method available on the WindowInteropHelper: public void InitHwnd() { var helper = new WindowInteropHelper(this); helper.EnsureHandle(); } (thanks to Thomas Levesque for pointing this out.) If you are targeting an older version of the .NET Framework, the easiest way is to show … Read more