flex BindableʹÓý²½â

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="horizontal">
 <mx:Panel width="392" height="300" layout="absolute">
  <mx:Label x="19" y="10" text="{user}" width="171" height="20"/>
  <mx:Button x="216" y="8" label="²âÊÔBindable" click="bind()" width="105"/>
  <mx:DataGrid x="19" y="58" dataProvider="{arr}">
   <mx:columns>
    <mx:DataGridColumn headerText="year" dataField="year"/>
    <mx:DataGridColumn headerText="city" dataField="city"/>
    <mx:DataGridColumn headerText="provice" dataField="provice"/>
    <mx:DataGridColumn headerText="total" dataField="total"/>
   </mx:columns>
  </mx:DataGrid>
 </mx:Panel>
 
 <mx:Script>
  <![CDATA[
   import mx.controls.Alert;
   import mx.collections.ArrayCollection;
   
   [Bindable]
   private var user:String="HELLO";
   [Bindable]
   private var arr:ArrayCollection=new ArrayCollection([
   {year:2009,city:"Shanghai",provice:"ÉϺ£",total:580000},
   {year:2009,city:"Beijing",provice:"ºÓ±±Ê¡",total:7852020},
   {year:2009,city:"Nanjing",provice:"½­ËÕÊ¡",total:895145},
   {year:2009,city:"Hangzhou",provice:"Õã½­Ê¡",total:4132415}]);
   
   //ÐÞ¸ÄÁ˰󶨵ÄuserºÍarr£¬²¢Ã»ÓÐÐÞ¸ÄlabelºÍdatagrid
   private function bind():void{
    this.user="HEllo22";
    arr.removeItemAt(3);
   }
  ]]>
 </mx:Script>
</mx:Application>