flex拖拽使用6

<mx:VBox horizontalAlign="center" verticalAlign="middle" height="100%" width="5%">   <mx:Button label="选择&gt;&gt;" buttonMode="true" useHandCursor="true" click="chooseMenu()"/>   <mx:Button label="&lt;&lt;移除" buttonMode="true" useHandCursor="true" click="removeMenu()"/>  </mx:VBox>  <mx:DataGrid id="rightDg" width="45%" height="100%" dropEnabled="true" dataProvider="{_roleMenuArray}"      dragDrop="dragIt(event)"  allowMultipleSelection="true">   <mx:columns>     <mx:DataGridColumn headerText="菜单名称" dataField="menuName" width="150">      <mx:itemRenderer>       <mx:Component>        <mx:Label text="{data.menuName}"  selectable="true"/>       </mx:Component>      </mx:itemRenderer>     </mx:DataGridColumn>     <mx:DataGridColumn headerText="菜单描述" dataField="menuDesc">      <mx:itemRenderer>       <mx:Component>        <mx:Label  text="{data.menuDesc}"  selectable="true"/>       </mx:Component>      </mx:itemRenderer>     </mx:DataGridColumn>   </mx:columns>  </mx:DataGrid> <mx:HBox width="100%" horizontalAlign="center">  <mx:Button  label="确定" styleName="certainBtn" buttonMode="true" useHandCursor="true"  click="updateRoleMenu()"/> </mx:HBox>