[flexcoders] Overriding Combobox and ListBase

[John Luke Mills]

I am trying to modify Combobox so one can type multiple characters into a
non-editable drop-down.  Combobox.as uses ListBase.as.  In ListBase there is
the following:

 
//--------------------------------------------------------------------------
    //
    //  Methods: Keyboard lookup
    //
 
//--------------------------------------------------------------------------

    /**
     *  Tries to find the next item in the data provider that
     *  starts with the character in the <code>eventCode</code> parameter.
     *  You can override this to do fancier typeahead lookups.  The search
     *  starts at the <code>selectedIndex</code> location; if it reaches
     *  the end of the data provider it starts over from the beginning.
     *
     *  @param eventCode The key that was pressed on the keyboard
     *  @return <code>true</code> if a match was found
     */
    protected function findKey(eventCode:int):Boolean
    {
        var tmpCode:int = eventCode;
        var junk:int = 4;
        junk += 4;
        
        
        return tmpCode >= 33 &&
               tmpCode <= 126 &&
               findString(String.fromCharCode(tmpCode));
    }

What do I have to do to have my own version of this?  Various attempts to
make my own copy or extend and override this function  haven't worked.

Thanks,  John Luke Mills