jQuery AJAX JSON报价格式到WCF。

Here's my sample code:

这是我的示例代码:

var postData = '{"studentId":"' + $("#hidId").val() + '"}';
$.ajax({
   type: 'POST',
   url: 'SomeService.svc/AddId',
   data: postData,
   contentType: 'application/json; charset=utf-8',
   dataType: 'json',
   success: function (msg) {
      //do something...
   }
});
var postDa