将ArrayCollection转换成xml

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009"  creationComplete="application1_creationCompleteHandler()"
               xmlns:s="library://ns.adobe.com/flex/spark" 
               xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600">
    <s:layout>
        <s:VerticalLayout horizontalAlign="center" verticalAlign="middle"/>
    </s:layout>
    <fx:Declarations>
        <!-- 将非可视元素（例如服务、值对象）放在此处 -->
        <s:HTTPService id="http" url="data/data.xml" resultFormat="e4x" result="httpservice1_resultHandler(event)"/>
    </fx:Declarations>
    <fx:Script>
        <![CDATA[
            import mx.collections.ArrayCollection;
            import mx.controls.Alert;
            import mx.rpc.events.ResultEvent;
            [Bindable]
            private var d:XML;
            [Bindable]
            private var dgdp:ArrayCollection=new ArrayCollection();
            private function arrToXml():void{
                var root:XML=<root/>;
                for(var i:int=0;i<dgdp.length;i++){
                    var node:XML=new XML(<node/>);
                    node.score=dgdp[i].score;
                    node.classes=dgdp[i].classes;
                    node.value=dgdp[i].value;
                    root.appendChild(node);
                }
                Alert.show(root.toXMLString());
            }
            protected function application1_creationCompleteHandler():void
            {
                http.send();
                
            }
            protected function httpservice1_resultHandler(event:ResultEvent):void
            {
                d=event.result as XML;
                trace(d);
                for each (var xml:XML in d..des){
                    var o:Object=new Object();
                    o.score=xml.@score;
                    o.classes=xml.@classes;
                    o.value=xml.@value;
                    dgdp.addItem(o);
                }
                arrToXml();
            }
        ]]>
    </fx:Script>
</s:Application>