c# SendKey to a hidden window

Question

I have a window which is hidden and I would like to send a keypress to it. An example of what I'm trying to achieve is an app that will send the key F5 to a web browser which wasn't the active window. The web browser would know to refresh the current page when the F5 keystroke is received.

I would also like to send a combination of keys to an application, e.g. Ctrl+S. One example of this usage could be a timed auto-save feature to use with applications which don't have autosave. This would spare me having to remember to save every 5 mins.

C# is my technology, does this sound realistic?

Answer 1

You can use WinApi for this purpose. SendMessage or PostMessage method to send desired message to your application. Here's C# definition of SendMessage

  [DllImport("user32.dll")]
            public static extern int SendMessage(
                  int hWnd,      // handle to destination window
                  uint Msg,       // message
                  long wParam,  // first message parameter
                  long lParam   // second message parameter
                  );

and define the message that you want to send like:

    public const int %WM_MESSAGE_HERE% = %value%;

Check Pinvoke - great resource containing WinApi method definitions for .NET

Answer 2

This CodeProject article shows how to send keystrokes to an external application (with C# source code).

Answer 3

This should be possible, look at www.pinvoke.net and search for sendinput, that page should tell you everything you need to know, also how to find the window (look for findwindow)