Trapping shift, escape and return keys for a ComboBox

MyComboBox::MyComboBox(zWindow *w,zSizer *s,DWORD style_, const char
*c,int i)
  :zComboBoxFull(w,s,style_,c,i){
        add(Item1);
        add(Item2);
        add(Item3);

        // Add event handler, notice the getText() method, this is the text portion of the ComboBox
        XtAddEventHandler(getText(),KeyPressMask,False,(XtEventHandler)MyComboBox::keybInput,
               
(XtPointer) this);
        show();
}

void MyComboBox::keybInput(Widget w, XtPointer ehTag, XEvent *xev,
Boolean *contin) {
        KeySym key;
        char buf[20];
        buf[0] =0;
        int len =0;
        if (xev->type  ==
KeyPress) {
               
len = XLookupString((XKeyEvent*) xev,buf,20,&key,&app->xcompose);
               
if (len == 0) return;
               
// trap keystrokes here
               
if(key == XK_Return) printf(Enter 
);
               
if(key == XK_Escape) printf(Escape 
);
               
if(key == XK_Shift_L) printf(Shift 
);
        }

}