JSON not parsed into custom object

Question

Please see the AJAX below:

 <script type="text/javascript" src="Javascript/json2.js"></script>
 <script type="text/javascript" src="Javascript/jquery-1.11.1.min.js"></script>
 <script type = "text/javascript">
 function GetData() {
 $.ajax({
 type: "POST",
 url: "JSONExample.aspx/GetPerson",
 contentType: "application/json; charset=utf-8",
 dataType: "text",
 success: OnSuccess(),
 //async: false,
 failure: function (response) {
 alert('there was an error counting possibles')
 }
 });
 function OnSuccess() {
 return function (response) {
 alert(response);
 window.location.href("JSONExample.aspx?id=" + response);
 }
 }
 }
 GetData()
 </script>

and the server side code below:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.Services;
using Newtonsoft.Json;
namespace SerializeAndDeserializeJSON
{
 //[Serializable]
 public class Person
 {
 public String Name;
 public int Age;
 }
 public partial class JSONExample : System.Web.UI.Page
 {
 protected void Page_Load(object sender, EventArgs e)
 {
 if ((Request.QueryString["id"]== null)==false)
 {
 var json = Request.QueryString["id"];
 var person = JsonConvert.DeserializeObject<Person>(json); //person is null
 }
 }
 [System.Web.Services.WebMethod]
 public static Person GetPerson()
 {
 Person p1 = new Person();
 p1.Name = "Ian";
 p1.Age=35;
 return p1;
 }
 }
}

In the page load the Person object values are as follows after the page load:

Name: null Age: 0

The name should be Ian and the Age should be 35. What am I doing wrong?

• Balaji Marimuthu: check your response is null, change dataType to json
• Matteo Marciano - MSCP: Is the Json object invalid inside the OnSuccess function?

Answer 1

What am I doing wrong?

Try setting dataType to json instead of text:

dataType: 'json'

And then send the javascript object as a JSON string in the id parameter:

window.location.href("JSONExample.aspx?id=" + encodeURIComponent(JSON.stringify(response.d)));

Notice that we are using response.d here because ASP.NET WebMethods serialize the responses using this special property.

Also you probably want to use public properties instead of fields for your model:

public class Person
{
 public string Name { get; set; }
 public int Age { get; set; }
}

Some frameworks choke on fields.

• w0051977: Thanks. However, this produces an error on the server side which says: "Could not cast or convert from System.String to SerializeAndDeserializeJSON.Person."
• Darin Dimitrov: What's the value of the id parameter that you get on the server?
• w0051977: \"{\\\"d\\\":{\\\"__type\\\":\\\"SerializeAndDeserializeJSON.Person\\\",\\\"Name\\\":\\\"Ian\\\",\\\"Age\\\":35}}\
• Darin Dimitrov: OK, I see the problem. Use dataType: 'json' and then JSON.stringify(response.d). I have updated my answer to reflect this change. The caveat is to use response.d.
• w0051977: Thanks. That did it.