Hi.
You can use the following events to do what you want:

Events events = _applicationObject.Events;
// Must save _textDocumentKeyPressEvents globally, or GC will remove
it soon
TextDocumentKeyPressEvents _textDocumentKeyPressEvents =
((Events2)events).get_TextDocumentKeyPressEvents(null);

_textDocumentKeyPressEvents.BeforeKeyPress +=
_textDocumentKeyPressEvents_BeforeKeyPress;
_textDocumentKeyPressEvents.AfterKeyPress +=
_textDocumentKeyPressEvents_AfterKeyPress;

public void _textDocumentKeyPressEvents_BeforeKeyPress(string
Keypress, TextSelection Selection, bool InStatementCompletion, ref
bool CancelKeypress) {
    if (Keypress[0] == ....) {
        CancelKeypress = true;
    }
}