FLEX 动态添加事件

<?xml version="1.0"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
layout="absolute"
verticalAlign="middle"
backgroundColor="white"
initialize="init()">
<mx:Script>
<![CDATA[
import mx.controls.Alert;
import mx.events.CloseEvent;
private function init():void
{
Ind.addEventListener(Event.CHANGE,Ind_changeHandler);
}
protected function Ind_changeHandler(event:Event):void
{
Alert.show("Ind");
}
]]>
</mx:Script>
<mx:RadioButton x="337" y="42" groupName="showModel" label="Individual" id="Ind" selected="true"/>
</mx:Application>