flex中DropDownList的完整实例

<?xml version="1.0" encoding="utf-8"?>
<!---
サンプル画面
-->
<mx: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="800"
    minHeight="400">
 <fx:Script>
  <![CDATA[
   import mx.controls.Alert;
   //  import flash.events.Event;
   import mx.collections.ArrayCollection;
   //下拉框的数据集  
   [Bindable]
   public static var fileNameTypeDropDownList:ArrayCollection=new ArrayCollection([{id: 0,label: 'Flag文件'},{id: 1,label: '固定文件名'},{id: 2,label: '正则表达式'}]);

   //获取DropDownList选中元素的索引  
   public static function getSelectedindexByResult(list:ArrayCollection,key:String,result:Object):int
   {
    var selectedindex:int=0;
    try
    {
     for (var i:int=0; i < list.length; i++)
     {
      if (list[i][key] == result)
      {
       selectedindex=i;
       break;
      }
     }
    }
    catch (e:Error)
    {
     Alert.show(e.message);
    }
    return selectedindex;
   }
//   var index:int=getSelectedindexByResult(fileNameTypeDropDownList,'id',data['file_name'])
  ]]>
 </fx:Script>
 <s:Group id="contentsBody"
    styleName="contentsBody"
    width="100%">
  <s:VGroup id="viewId"
      styleName="viewId"
      width="100%"
      horizontalAlign="right">
  </s:VGroup>
  <s:DropDownList id="userGroupComboBox"
      requireSelection="true"
      dataProvider="{fileNameTypeDropDownList}"
      click="getSelectedindexByResult(fileNameTypeDropDownList,data['file_name'])"/>
 </s:Group>

</mx:Application>