flex 问题请教

首先，感谢你们对问题的浏览。
刚才碰到这样一个问题：简单描述下，Flex表单提交，进行保存操作，返回ok,然后去做一个查询操作，为什么执行查询请求的httpService不会执行呢？
我刚接触FELX，这个问题亟待解决，还请高手指点。
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部分代码：
这是保存服务：
var httpService:HTTPService = new HTTPService();
httpService.url = properties.@dataSource;
httpService.resultFormat = "e4x";
httpService.addEventListener(FaultEvent.FAULT, onFaultHttpService);
httpService.addEventListener(ResultEvent.RESULT, onResultHttpService);
httpService.send();

private function onResultHttpService ():void{
if(){……
queryChartData();
}

private function queryChartData ():void{
var httpService:HTTPService = new HTTPService();
httpService.url = properties.@dataSource;
httpService.resultFormat = "e4x";
httpService.addEventListener(FaultEvent.FAULT, onFaultHttpService);
httpService.addEventListener(ResultEvent.RESULT, onResultHttpService);
httpService.send(); }
请教为什么不会执行 queryChartData（）中的httpservice?