How can I programmatically generate keypress events?

wish helps you 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 }
  );

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

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

this will help I am developing a chrome extension that runs some javascript on a particular web page. , try dispatchEvent/fireEvent methods

I wish this helpful for you You can try PyQt or wxPython
Here is a link for how to handle key press with PyQt - http://www.saltycrane.com/blog/2008/01/how-to-capture-tab-key-press-event-with/

fixed the issue. Will look into that further Have a look at this article, particularly the following snippet of code:

/* synthesize Alt+O key press */
event = gdk_event_new (GDK_KEY_PRESS);
event->key.window = widget->window;

event->key.window = g_object_ref (widget->window);

I hope this helps . The eventFilter() method needs a boolean result, or 0/1, to return if an event is relevant or not (the filter part). When you return False the event is not blocked, and will hit his target, this lets the application handle the event in a normal way.
In your example, when an expected key is pressed (this is a relevant event), you need to return 1 or True to "intercept" it and prevent the program to handle it, since you provide your own process. In the other cases, you can call the super method like you did :

def eventFilter(self, obj, event):
    if event.type() == QtCore.QEvent.KeyPress:
        print("keypress")

        if event.key() == QtCore.Qt.Key_Escape:
            self.close()
            return 1
        if event.key() == QtCore.Qt.Key_Tab:
            print("Tab")
            return 1

    return super().eventFilter(obj, event)