flex DataGrid 取得点击的值

1：方法
       private function tt():void
        {
        var obj:Object=dataGrid1.indexToItemRenderer(dataGrid1.selectedIndex).data///.label;//.itemRenderer.newInstance();
        //obj.label
        Alert.show(obj.label);
        }




2：设置属性
<mx:DataGrid height="100%"
        dragEnabled="true"
        dataProvider="{NormalActivityCodeProvider}"
        dragEnter="onDragEnter(event)"
      
        dragDrop="onGridDragDrop(event)"
click="tt()"
        dragMoveEnabled="true"
        width="100%" rollOver="mous()" id="dataGrid1">