@import url(http://www.blogjava.net/CuteSoft_Client/CuteEditor/Load.ashx?type=style&file=SyntaxHighlighter.css);@import url(/css/cuteeditor.css); @import url(http://www.blogjava.net/CuteSoft_Client/CuteEditor/Load.ashx?type=style&file=SyntaxHighlighter.css);@import url(/css/cuteeditor.css);
//验证并更新此对象的属性和布局
Tree.validateNow();
for each (var item:Object in Tree.dataProvider)
{
//打开或关闭指定项目下的所有树项目。如果设置 dataProvider 之后立即调用 expandChildrenOf()，则您可能看不到正确的行为。您应该等待对组件进行验证或调用 validateNow() 方法。
Tree.expandChildrenOf(item, true);}

第二种方式


 1  <? xml version="1.0" encoding="utf-8" ?>
 2  < s:Application  xmlns:fx ="http://ns.adobe.com/mxml/2009"  
  3                 xmlns:s ="library://ns.adobe.com/flex/spark"  
  4                 xmlns:mx ="library://ns.adobe.com/flex/mx"  minWidth ="955"  minHeight ="600"
 5                 creationComplete ="onInit()" >
 6       < fx:Declarations >
 7           <!--  将非可视元素（例如服务、值对象）放在此处  -->
 8          
  9           < fx:XML  id ="xml"  xmlns ="" >
10               < node  id ="#"  label ="所有" >
11                   < node  id ="101"  label ="Name101" >
12                       < node  id ="10101"  label ="Name10101" />
13                       < node  id ="10102"  label ="Name10102" />
14                       < node  id ="10103"  label ="Name10103" />
15                   </ node >
16                   < node  id ="102"  label ="Name102" >
17                       < node  id ="10201"  label ="Name10201" />
18                       < node  id ="10202"  label ="Name10202" />
19                   </ node >
20                   < node  id ="103"  label ="Name103" >
21                       < node  id ="10301"  label ="Name10301" />
22                   </ node >
23               </ node >
24           </ fx:XML >
25       </ fx:Declarations >
26      
 27       < fx:Script >
28           <![CDATA[
29              private function onInit():void{
 30                  tree.selectedIndex=0;
 31                  tree.callLater(expand,null);
 32              }
 33              private function expand():void{
 34                  tree.expandItem(tree.selectedItem,true);
 35                  //这里可以随便指定展开的节点，如果超出默认展开最后一个根节点
 36                  tree.selectedIndex=1;
 37                  tree.expandItem(tree.selectedItem,true);
 38              }
 39           ]]>
40       </ fx:Script >
41       < mx:Tree  id ="tree"  x ="73"  y ="36"  width ="200"  height ="217"  dataProvider ="{xml}"  labelField ="@label" ></ mx:Tree >
42  </ s:Application >
43