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Ò»¡¢HTTPService
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<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" initialize="initializeHandler(event)">
<mx:Script>
<!--[CDATA[
private function initializeHandler(event:Event):void {
countriesService.send();
}
private function changeHandler(event:Event):void {
statesService.send();
}
]]>
</mx:Script>
<!-- ÔØÈë´¿¾²Ì¬µÄxmlÊý¾Ý -->
<mx:HTTPService id="countriesService" url="http://www.rightactionscript.com/states/xml/countries.xml" />
<!-- ÔØÈëÓÉphpÉú³ÉµÄxmlÊý¾Ý -->
<mx:HTTPService id="statesService" url="http://www.rightactionscript.com/states/xml/states.php">
<!-- ÒÔϱêÇ©¾ÍÊÇÒª·¢Ë͵½·þÎñ¶ËµÄÊý¾ÝÁË,¿ÉÒÔÕâÑùÀí½â:ÓÐÒ»¸öÃûΪcountryµÄ±äÁ¿,ËüµÄֵΪ»¨À¨ºÅ{}ÀïµÄÄÚÈÝ -->
<mx:request>
<country>{country.value}</country>
</mx:request>
</mx:HTTPService>
<mx:VBox>
<!-- ´Ë¿Ø¼þµÄÊý¾ÝÓɵÚÒ»¸ö<mx:HTTPService/>¿Ø¼þ½ÓÊÕµÄÄÚÈÝÌṩ,²¢ÇÒÓÉÕâ¸öComboBox¿ØÖÆ×ŵڶþ¸öComboBoxËùÒªÏÔʾµÄÄÚÈÝ -->
<mx:ComboBox id="country" dataProvider="{countriesService.lastResult.countries.country}"
change="changeHandler(event)" />
<!-- ÏÂÃæµÄComboBoxÒѾ­°ó¶¨ÁË{statesService.lastResult.states.state},ËæËüµÄÊý¾Ý¸Ä±ä¶ø¸Ä±ä -->
<mx:ComboBox dataProvider="{statesService.lastResult.states.state}" />
</mx:VBox>
</mx:Application>  
¶þ¡¢URLLoader
³ÌÐò´úÂ룺
<?xml version="1.0" encoding="utf-8"?>
<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" initialize="initializeHandler(event)">
<mx:Script>
<!--[CDATA[
private var _countriesService:URLLoader;
private var _statesService:URLLoader;
private function initializeHandler(event:Event):void {
_countriesService = new URLLoader();
_countriesService.addEventListener(Event.COMPLETE, countriesCompleteHandler);
_countriesService.load(new URLRequest("http://www.rightactionsc