flex 绑定元数据

<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"
layout="horizontal" viewSourceURL="srcview/index.html">
<mx:Script>
<![CDATA[

[Bindable]
[Embed("http://longstep.cn/closed.png")]
public var myFolderClosedIcon:Class;
[Bindable]
[Embed("http://longstep.cn/opened.png")]
public var myFolderOpenIcon:Class;

[Bindable]
[Embed("http://longstep.cn/pdf.png")]
public var pdfIcon:Class;
[Bindable]
[Embed("http://longstep.cn/doc.png")]
public var docIcon:Class;

]]>
</mx:Script>
<mx:XML id="xmlData" xmlns="">
<rootNode>
<directory label="dir">
<file icon="pdfIcon" label="label1" />
<file icon="docIcon" label="label2" />
</directory>
<directory label="dir1">
<file icon="pdfIcon" label="label3" />
<file icon="docIcon" label="label4" />
</directory>
</rootNode>
</mx:XML>
<mx:Panel title="Tree">

<mx:Tree
borderStyle="none"
backgroundAlpha="0"
labelField="@label"
iconField="@icon"
width="300"
height="200"
id="treeAdmin"
folderOpenIcon="{myFolderOpenIcon}"
folderClosedIcon="{myFolderClosedIcon}"
dataProvider="{xmlData.directory}" alpha="1" />
</mx:Panel>
</mx:Application>