设置垂直滚动位置不工作

尝试添加此代码,我正在工作,因此无法验证它是否有效,希望如此:

//Initialize the Vbox
public var myVbox:VBox = new VBox();
//Define the function which rebuilds the Vbox
public function rebuildVbox():VBox{  
myVbox.verticalScrollPosition=200;
return myVbox
}
//Define your event.complete function which sets the verticalScrollPosition  
//after the drag drop
public function setVerticalScrollPosition():void{
    myVbox.addEventListener(Event.COMPLETE,function(event:Event):void{
            rebuildVbox()
            });
    }