flex navigateToURL传送的值 C#取不到解决方案

flex navigateToURL传送的值 C#取不到
flex里这样写

C# code

    private const _strDownScript:String="http://localhost:3269/Web/DownFile.aspx";          var LoadVars:URLVariables = new URLVariables();     LoadVars.filename = //文件名称     LoadVars.path=//文件路径     var request1:URLRequest = new URLRequest();     request1.data = LoadVars;     request1.url = _strDownScript     request1.method = URLRequestMethod.POST;     navigateToURL(request1,"_blank");

然后我在C#里用
string fName = Convert.ToString(Request.Form["filename"]);
string fPath = Convert.ToString(Request.Form["path"]);  
取不到值。 
应该怎么取呢 请大虾指点 多谢

[解决办法]
不是Request.query..那个什么嘛