Это будет работать
class KeyHandle
{
private static Int32 WM_KEYDOWN = 0x100;
private static Int32 WM_KEYUP = 0x101;
[return: MarshalAs(UnmanagedType.Bool)]
[DllImport("user32.dll", SetLastError = true)]
static extern bool PostMessage(IntPtr hWnd, int Msg,
System.Windows.Forms.Keys wParam, int lParam);
public static void SendKey(IntPtr hWnd, System.Windows.Forms.Keys key)
{
PostMessage(hWnd, WM_KEYDOWN, key, 0);
}
}
Метод вызова:
KeyHandle.SendKey(this.webBrowser.Handle, Keys.PageDown);