<?xml version="1.0" encoding="utf-8"?> <!-- Tree control example. --> <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml">     <!--下面是样式-->     <mx:Style >         Tree     {             verticalScrollBarStyleName: treeVerticalScrollBar;         selectionColor: #417597;      /*为默认、打开、关闭、有子项等几个状态添加不同的ico*/         defaultLeafIcon: Embed(source="longstep/icon/sharp_grey/gif/base.gif");         folderOpenIcon: Embed(source="longstep/icon/sharp_grey/gif/vote_yes.gif");         folderClosedIcon: Embed(source="longstep/icon/sharp_grey/gif/options.gif");         disclosureOpenIcon: Embed(source="longstep/icon/sharp_grey/gif/pause.gif");     }     .treeVerticalScrollBar     {         borderColor: #f00;     }     </mx:Style> <mx:Script> <![CDATA[         //绑定数据，定义xml类型变量用于存放选中节点 [Bindable] public var selectedNode:XML; //当tree发生change事件时的事件 public function treeChanged(event:Event):void { //将选中的节点转换成xml，赋予selectedNode，as为转换类型 selectedNode=Tree(event.target).selectedItem as XML; }      //tree有3个事件使用较多，change、itemClick、itemOpen、itemClose      //change:选中列改变时被触发      //itemClick:点击某一列时触发      //itemOpen:节点展开时触发      //itemClose:节点关闭时触发 ]]> </mx:Script> <!--XMLList作为数据源是最适合于tree组件的--> <mx:XMLList id="treeData">      <node label="Mail Box">      <node label="Inbox">      <node label="Marketing"/>      <node label="Product Management"/>      <node label="Personal"/>      </node>      <node label="Outbox">      <node label="Professional"/>      <node label="Personal"/>      </node>      <node label="Spam"/>      <node label="Sent"/>         </node>     </mx:XMLList> <mx:Panel title="Tree Control Example" height="75%" width="75%" paddingTop="10" paddingLeft="10" paddingRight="10" paddingBottom="10"> <mx:Label width="100%" color="blue" text="Select a node in the Tree control."/> <mx:HDividedBox width="100%" height="100%"> <!--@表示xml中间点的属性，如：@label表示label属性的值--> <!--dataProvider="{treeData}"表示绑定数据，数据源可以是XML也可以是XMLList--> <mx:Tree id="myTree" width="50%" height="100%" labelField="@label" showRoot="false" dataProvider="{treeData}" change="treeChanged(event)"/> <mx:TextArea height="100%" width="50%" text="Selected Item: {selectedNode.@label}"/> </mx:HDividedBox> </mx:Panel> </mx:Application>