flex mx_internal_uid的在数据传递时重复的解决方法

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">
 <mx:Script>
  <![CDATA[
   import mx.utils.UIDUtil;
   import mx.collections.ArrayCollection;
   import mx.utils.ObjectUtil;
   
   [Bindable]
   public var dataArr:Array = [{label:"Red",data:"#FF0000"},
    {label:"Green",data:"#00FF00"},
    {label:"Blue",data:"#0000FF"}
   ];
   [Bindable]
   public var problemArr:Array = new Array();
   
   private function addFromTopDG():void {
    problemArr.push(fromDG.selectedItem);
    //problemArr.push(ObjectUtil.copy(fromDG.selectedItem));
    toDG.dataProvider = problemArr;
   }
   
   private function addFromTopDG2():void {
    var obj:Object = ObjectUtil.copy(fromDG.selectedItem);
    obj.mx_internal_uid = UIDUtil.createUID();
    //这里千万不要直接fromDG.selectedItem.mx_internal_uid = UIDUtil.createUID();
    //因为上面说过这样引用关系还存在。
    (toDG.dataProvider as ArrayCollection).addItem(obj);
    obj = null;//这个就靠自己的CODE 风格啦，不要也没关系
   }
  ]]>
 </mx:Script>
 <mx:DataGrid id="fromDG" width="600" height="200" dataProvider="{dataArr}">
  <mx:columns>
   <mx:Array>
    <mx:DataGridColumn width="300" datafield="mx_internal_uid"/>
    <mx:DataGridColumn datafield="label"/>
    <mx:DataGridColumn datafield="data"/>
   </mx:Array>
  </mx:columns>
 </mx:DataGrid>
 <mx:Button label="Add from Top_DG" click="addFromTopDG()"/>
 <mx:DataGrid id="toDG" width="600" height="200" dataProvider="{problemArr}">
  <mx:columns>
   <mx:Array>
    <mx:DataGridColumn width="300" datafield="mx_internal_uid"/>
    <mx:DataGridColumn datafield="label"/>
    <mx:DataGridColumn datafield="data"/>
   </mx:Array>
  </mx:columns>
 </mx:DataGrid>
</mx:Application>

来源：

http://www.voidcn.com/article/p-relvxpxg-bra.html