flash datagrid嵌入checkbox

代码如下：

package
{
    import fl.controls.CheckBox;
    import fl.controls.listClasses.ICellRenderer;
    import fl.controls.listClasses.ListData;
    import flash.events.Event;
    import fl.core.InvalidationType;
    public class CheckBoxRenderer extends CheckBox implements ICellRenderer
    {
        private var _listData:ListData;
        private var _data:Object;

        public function CheckBoxRenderer(){
           super();
           addEventListener(Event.CHANGE, onCheckChange);
        }
        public function set data(d:Object):void{
           _data = d;
           label = "";
           _selected = (_data["checked"]=='true')?true:false;
        }
        public function get data():Object {
           return _data;
        }
        public function get selectedItem():Object {
           return _data;
        }
        public function get listData():ListData {
            return _listData;
        }
        public function set listData(value:ListData):void {
            _listData = value;
        }
        override public function get selected():Boolean {
            return _selected;
         }
       override public function set selected(value:Boolean):void {
       }
        public function onCheckChange(e:Event) {
             _selected = !_selected;
            _data["checked"] = (_selected==true)?'true':'false';
       }
     }
  }