flex调用webservice返回xml格式字符串，并遍历

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
			   xmlns:s="library://ns.adobe.com/flex/spark" 
			   xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600" creationComplete="init()">
	<fx:Script>
		<![CDATA[
			import mx.collections.ArrayCollection;
			import mx.controls.Alert;
			import mx.rpc.events.ResultEvent;
			import mx.rpc.soap.LoadEvent;
			import mx.rpc.soap.WebService;
			private var web:WebService;

			protected function init():void
			{
				web=new WebService();
				web.loadWSDL("http://10.19.1.55/staterain/rainSensor.asmx?WSDL");
				web.addEventListener(LoadEvent.LOAD,testConn);
				web.GetSensorState("-1");
				web.GetSensorState.addEventListener(ResultEvent.RESULT,getNum);
			}
			public function testConn(event:Event):void
			{
				lbl0.text="连接成功";
			}
			public function getNum(event:ResultEvent):void
			{
//				txt1.text=event.result.toString();
				var xmldata:XML=new XML(event.result);
//				for each ( var name:XML in xmldata.sensor ) {
//					Alert.show(name.sensorID);
//				} 
				Alert.show(xmldata..sensorID);	
//				for each ( var name:String in xmldata.sensor ) {
//					Alert.show(name);
//				}
				txt1.text=xmldata.toXMLString();
			}

		]]>
	</fx:Script>
	<s:layout>
		<s:BasicLayout/>
	</s:layout>
	<fx:Declarations>
		<!-- 将非可视元素（例如服务、值对象）放在此处 -->
		<fx:XML id="myData" xmlns="">
			<node lable="资料">
				<node lable="Music">
					<node lable="古典"/>
					<node lable="摇滚"/>
					<node lable="民歌"/>
				</node>
				<node lable="Movie">
					<node lable="法国"/>
					<node lable="美国"/>
				</node>
			</node>
		</fx:XML>
	</fx:Declarations>
	<s:Label x="18" y="17" text="标签" width="413" height="56" fontSize="36" id="lbl0"/>
	<mx:Tree x="438" y="148" width="310" height="291" labelField="@lable" dataProvider="{myData}"?
 folderOpenIcon="@Embed(source='../flex_src/weather/1.gif')" defaultLeafIcon="@Embed(source='../flex_src/weather/0.gif')"?
 folderClosedIcon="@Embed(source='../flex_src/weather/2.gif')"></mx:Tree>
<s:TextInput x="73" y="165" width="357" height="484" id="txt1"/>
	
</s:Application>