<?xml version="1.0" encoding="utf-8"?>  <mx:Application xmlns:mx="http://www.adobe.com/2006/mxml"     layout="vertical"     verticalAlign="middle"     backgroundColor="white">    <mx:Script>   <![CDATA[    import mx.utils.StringUtil;    import mx.controls.Alert;        [Bindable]    private var arr:Array=[     {name:"名字11",abbrev:"Al1"},     {name:"名字12",abbrev:"Al2"},     {name:"名字13",abbrev:"Al3"},     {name:"名字14",abbrev:"Al4"},    ];        private function comboBox_labelFunc(item:Object):String {     return StringUtil.substitute("{0} ({1})", item.@name, item.@abbrev);    }        private function comboBox_labelFunc_custom(item:Object):String {     return StringUtil.substitute("{0} ({1})", item.name, item.abbrev);    }            protected function button1_clickHandler(event:MouseEvent):void    {     if(this.comboBox2.selectedItem)      Alert.show(this.comboBox2.selectedItem.name);     else Alert.show("not selected");          if(this.comboBox.selectedItem)      Alert.show(this.comboBox.selectedItem.@name);     else Alert.show("not selected");         }       ]]>  </mx:Script>    <mx:XMLList id="statesXMLList">   <state abbrev="AL" name="Alabama" />   <state abbrev="AK" name="Alaska" />   <state abbrev="AZ" name="Arizona" />   <state abbrev="AR" name="Arkansas" />   <state abbrev="CA" name="California" />   <state abbrev="CO" name="Colorado" />   <state abbrev="CT" name="Connecticut" />  </mx:XMLList>  <mx:ComboBox id="comboBox2"      prompt="Please select a aa..."      dataProvider="{arr}"      labelFunction="comboBox_labelFunc_custom" />  <mx:Button label="按钮" click="button1_clickHandler(event)"/>    <mx:ComboBox id="comboBox"      prompt="Please select a State..."      dataProvider="{statesXMLList}"      labelFunction="comboBox_labelFunc" />       </mx:Application>