可以使用DataContractJsonSerializer类将类型实例序列化为JSON字符串，并将JSON字符串反序列化为类型实例。 DataContractJsonSerializer在System.Runtime.Serialization.Json命名空间下
，.NET Framework 3.5包含在System.ServiceModel.Web.dll中，需要添加对其的引用；.NET Framework 4在System.Runtime.Serialization中。
利用DataContractJsonSerializer序列化和反序列化的代码：
1: using System;
2: using System.Collections.Generic;
3: using System.Linq;
4: using System.Web;
5: using System.Runtime.Serialization.Json;
6: using System.IO;
7: using System.Text;
8:
9: /// <summary>
10: /// JSON序列化和反序列化辅助类
11: /// </summary>
12: public class JsonHelper
13: {
14: /// <summary>
15: /// JSON序列化
16: /// </summary>
17: public static string JsonSerializer<T>(T t)
18: {
19: DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));
20: MemoryStream ms = new MemoryStream();
21: ser.WriteObject(ms, t);
22: string jsonString = Encoding.UTF8.GetString(ms.ToArray());
23: ms.Close();
24: return jsonString;
25: }
26:
27: /// <summary>
28: /// JSON反序列化
29: /// </summary>
30: public static T JsonDeserialize<T>(string jsonString)
31: {
32: DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));
33: MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(jsonString));
34: T obj = (T)ser.ReadObject(ms);
35: return obj;
36: }
37: }
序列化Demo：
简单对象Person：
1: public class Person
2: {
3: public string Name { get; set; }
4: public int Age { get; set; }
5: }
序列化为JSON字符串：
1: protected void Page_Load(object sender, EventArgs e)
2: {
3: Person p = new Person();
4: p.Name = "张三";
5: p.Age = 28;
6:
7: string jsonString = JsonHelper.JsonSerializer<Person>(p);
8: Response.Write(jsonString);
9: }
输出结果：
{"Age":28,"Name":"张三"}
反序列化Demo：
1: protected void Page_Load(object sender, EventArgs e)
2: {
3: string jsonString = "{\"Age\":28,\"Name\":\"张三\"}";
4: Person p = JsonHelper.JsonDeserialize<Person>(jsonString);
5: }
ASP.NET中的JSON序列化和反序列化还可以使用JavaScriptSerializer，在 System.Web.Script.Serializatioin命名空间下，需引用System.Web.Extensions.dll.也可以使用 JSON.NET.