How can I send keypresses to a running process object?

I am trying to make C# launch an application (in this case open office), and start sending that application keypresses such that it would appear as though someone is typing. So ideally, I would be able to send a running open office process the keypress for the letter "d", and open office would then type d on 开发者_JAVA技巧the paper. Can anyone give me direction as per how to go about this? I have tried to do the following:

p = new Process();
p.StartInfo.UseShellExecute = true;
p.StartInfo.CreateNoWindow = false;
p.StartInfo.FileName = processNames.executableName;

p.Start();

p.StandardInput.Write("hello");

But that doesn't get me the desired effect - I don't see the text typed out in open office.

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You have to do this via Win32 sendmessages: The basic idea is like this:

Fist you need a pointer to the launched process window:

using System.Runtime.InteropServices;

[DllImport("user32.dll", SetLastError = true)]
private static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

private void button1_Click(object sender, EventArgs e)
{
  // Find a window with the name "Test Application"
  IntPtr hwnd = FindWindow(null, "Test Application");
}

then use SendMessage or PostMessage (preferred in your case I guess):

http://msdn.microsoft.com/en-us/library/ms644944(v=VS.85).aspx

In this message specify the correct message type (e.g. WM_KEYDOWN) to send a keypress:

http://msdn.microsoft.com/en-us/library/ms646280(VS.85).aspx

Have a look at PInvoke.net to get PInvoke sourcecode.

Alternatively you can use the SendKeys.Send (.Net) method after using FindWindow to bring that window to the foreground. However that is somewhat unreliable.

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I did this using SetForegroundWindow and SendKeys.

I used it for this.

[DllImport("user32.dll", ExactSpelling = true, CharSet = CharSet.Auto)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool SetForegroundWindow(IntPtr hWnd);

public void SendText(IntPtr hwnd, string keys)
{
    if (hwnd != IntPtr.Zero)
    {
        if (SetForegroundWindow(hwnd))
        {
            System.Windows.Forms.SendKeys.SendWait(keys);
        }
    }
}

This can be used as simply as this.

Process p = Process.Start("notepad.exe");
SendText(p.MainWindowHandle, "Hello, world");