Flex中使用filter过滤数据

 <?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"  creationComplete="init()" layout="absolute" fontSize="12" backgroundGradientAlphas="[1.0, 1.0]" backgroundGradientColors="[#FCFCFC, #FCFCFC]">
 <mx:Script>
  <![CDATA[
  import mx.collections.ArrayCollection;
  import mx.events.CloseEvent;
  public var temp:String="";
  [Bindable]private var filteredArr:Array;
     [Bindable]private var plistArr:Array;
     [Bindable]
        public var users:Array =[{id:1,username:"aaa", dept:"开发部"},
                        {id:2,username:"bbb", dept:"产品部"},
                     {id:3,username:"ccc", dept:"开发部"},
                 {id:4,username:"ddd", dept:"产品部"}];

      private function init():void{
        filteredArr = users.filter(removedDuplicates);
      }
      private var keys:Object = {};
      private function removedDuplicates(item:Object, idx:uint, arr:Array):Boolean {
                if (keys.hasOwnProperty(item.dept)) {
                    return false;
                } else {
                    keys[item.dept] = item;
                    return true;
                }
            }

      private function closeHandler(event:Event):void {
                temp=String(ComboBox(event.target).selectedItem.dept);
               plistArr=users.filter(conditionFunction);
            }

      private function conditionFunction(item:Object, idx:uint, arr:Array):Boolean {
                if (item.dept==temp){
                    return true ;
                }else{
                 return false;
                }

            }
  ]]>
 </mx:Script>
  <mx:Form width="293" height="152"  horizontalCenter="0" verticalCenter="0" borderStyle="solid">
    <mx:FormItem label="部门：" width="250">
       <mx:ComboBox   close="closeHandler(event);"  labelField="dept" dataProvider="{filteredArr}"  width="100%"></mx:ComboBox>
    </mx:FormItem>
    <mx:FormItem width="250">
       <mx:Repeater id="checkBoxRepeater" dataProvider="{plistArr}">
    <mx:CheckBox id="checkBox" label="{checkBoxRepeater.currentItem.username}"/>
   </mx:Repeater>

    </mx:FormItem>

 </mx:Form>
</mx:Application>