How can I programmatically generate keypress events in C#?

Question

How can I programmatically create an event that would simulate a key being pressed on the keyboard?

Answer 1

I've not used it, but SendKeys may do what you want.

Use SendKeys to send keystrokes and keystroke combinations to the active application. This class cannot be instantiated. To send a keystroke to a class and immediately continue with the flow of your program, use Send. To wait for any processes started by the keystroke, use SendWait.

System.Windows.Forms.SendKeys.Send("A");
System.Windows.Forms.SendKeys.Send("{ENTER}");

Microsoft has some more usage examples here.

Answer 2

Windows SendMessage API with send WM_KEYDOWN.

Answer 3

The question is tagged WPF but the answers so far are specific WinForms and Win32.

To do this in WPF, simply construct a KeyEventArgs and call RaiseEvent on the target. For example, to send an Insert key KeyDown event to the currently focused element:

  var key = Key.Insert;                    // Key to send
  var target = Keyboard.FocusedElement;    // Target element
  var routedEvent = Keyboard.KeyDownEvent; // Event to send

  target.RaiseEvent(
    new KeyEventArgs(
      Keyboard.PrimaryDevice,
      PresentationSource.FromVisual(target),
      0,
      key)
    { RoutedEvent=routedEvent }
  );

This solution doesn't rely on native calls or Windows internals and should be much more reliable than the others. It also allows you to simulate a keypress on a specific element.

Note that this code is only applicable to PreviewKeyDown, KeyDown, PreviewKeyUp, and KeyUp events. If you want to send TextInput events you'll do this instead:

  var text = "Hello";
  var target = Keyboard.FocusedElement;
  var routedEvent = TextCompositionManager.TextInputEvent;

  target.RaiseEvent(
    new new TextCompositionEventArgs(
      InputManager.Current.PrimaryKeyboardDevice,
      new TextComposition(InputManager.Current, target, text))
    { RoutedEvent = routedEvent }
  );

Also note that:

• Controls expect to receive Preview events, for example PreviewKeyDown should proceed KeyDown

• Using target.RaiseEvent(...) sends the event directly to the target without meta-processing such as accelerators, text composition and IME. This is normally what you want. On the other hand, if you really do what to simulate actual keyboard keys for some reason, you would use InputManager.ProcessInput() instead.

Answer 4

On the other hand, if you really do what to simulate actual keyboard keys for some >reason, you would use InputManager.ProcessInput() instead.

Thanks for a very useful post - I'm trying to use InputManager.ProcessInput() because I have an accelerator (CTRL) key I need to check. I am unclear about exactly how to do that - do you have a sample of the syntax I'd use?