带参数的POST上的Ajax调用在WCF中不起作用

Question

我的POST对WCF服务的ajax调用不适用于块内提供的参数，

 $("#btnPost").click(function(){
 //$.post("http://localhost:3700/TestService.svc/json_post/12345", //this works fine
        $.post("http://localhost:3700/TestService.svc/json_post",
        {
            id : "12345" // this is not working
        }, 
        function(data, status){

        alert("Data: " + data.DoWork_Result + "\nStatus: " + status);


        });
       });