flex 19 ComboBox ArrayCollection

ComboArrcol.mxml

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute">
 <mx:Panel width="250" height="200" layout="absolute" horizontalCenter="0" verticalCenter="0">
  <mx:ComboBox horizontalCenter="0" verticalCenter="0" dataProvider="{season}" close="closeHandler();" id="cb"></mx:ComboBox>
 </mx:Panel>
 <mx:Script>
  <![CDATA[
   import mx.controls.Alert;
   import mx.collections.ArrayCollection;
   [Bindable]
   public var season:ArrayCollection = new ArrayCollection(
    [{label:"Spring", data:1},{label:"Summer", data:2},
    {label:"Autumn", data:3},{label:"Winter", data:4}]);
   private function closeHandler():void{
    mx.controls.Alert.show("season: "+cb.selectedLabel+"\n"+"data: "+cb.selectedItem.data);
   }
  ]]>
 </mx:Script>
</mx:Application>