Flex 中 将NumericStepper控件不可操作或可操作更改

<?xml version="1.0" encoding="utf-8"?>

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
layout="vertical"
verticalAlign="middle"
backgroundColor="white" viewSourceURL="srcview/index.html">

<mx:Script>
<![CDATA[
private function checkBox_change(evt:Event):void {
var value:Boolean = checkBox.selected;
numericStepper.mx_internal::inputField.editable = value;
}
]]>
</mx:Script>

<mx:ApplicationControlBar dock="true">
<mx:Form styleName="plain">
<mx:FormItem label="editable:">
<mx:CheckBox id="checkBox"
selected="true"
change="checkBox_change(event);" />
</mx:FormItem>
</mx:Form>
</mx:ApplicationControlBar>

<mx:NumericStepper id="numericStepper"

                                              maximum="50"
   minimum="1"
  value="6"

  width="100" />

</mx:Application>