var user={"name":"张三","gender":"男","birthday":"1980-8-8"}

using System;
using SystemCollectionsGeneric;
using SystemLinq;
using SystemWeb;
using SystemRuntimeSerializationJson;
using SystemIO;
using SystemText;
 /// <summary>
 /// JSON序列化和反序列化辅助类
/// </summary>
 public class JsonHelper
{
  /// <summary>
  /// JSON序列化
  /// </summary>
  public static string JsonSerializer<T>(T t)
  {
   DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));
   MemoryStream ms = new MemoryStream();
   serWriteObject(ms, t);
   string jsonString = EncodingUTFGetString(msToArray());
   msClose();
   return jsonString;
  } 
  /// <summary>
  /// JSON反序列化
  /// </summary>
  public static T JsonDeserialize<T>(string jsonString)
  {
   DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));
   MemoryStream ms = new MemoryStream(EncodingUTFGetBytes(jsonString));
   T obj = (T)serReadObject(ms);
   return obj;
  }
 }

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

 protected void Page_Load(object sender, EventArgs e)
{
 Person p = new Person();
 pName = "张三";
  pAge = 28; 
 string jsonString = JsonHelperJsonSerializer<Person>(p);
  ResponseWrite(jsonString);
 }

{"Age":28,"Name":"张三"} 

  protected void Page_Load(object sender, EventArgs e)
{
  string jsonString = "{\"Age\":28,\"Name\":\"张三\"}";
  Person p = JsonHelper.JsonDeserialize<Person>(jsonString);
}

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

 Person p = new Person();
 p.Name = "张三";
 p.Age = 28;
 p.LastLoginTime = DateTime.Now; 
 string jsonString = JsonHelper.JsonSerializer<Person>(p);

{"Age":28,"LastLoginTime":"\/Date(1294499956278+0800)\/","Name":"张三"}

  using System;
 using SystemCollectionsGeneric;
 using SystemLinq;
 using SystemWeb;
 using SystemRuntimeSerializationJson;
 using SystemIO;
 using SystemText;
 using SystemTextRegularExpressions;
  
 /// <summary>
 /// JSON序列化和反序列化辅助类
 /// </summary>
 public class JsonHelper
 {
  /// <summary>
  /// JSON序列化
  /// </summary>
  public static string JsonSerializer<T>(T t)
  {
   DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));
   MemoryStream ms = new MemoryStream();
   serWriteObject(ms, t);
   string jsonString = EncodingUTFGetString(msToArray());
   msClose();
   //替换Json的Date字符串
   string p = @"\\/Date\((\d+)\+\d+\)\\/";
   MatchEvaluator matchEvaluator = new MatchEvaluator(ConvertJsonDateToDateString);
   Regex reg = new Regex(p);
   jsonString = regReplace(jsonString, matchEvaluator);
   return jsonString;
  }
 
  /// <summary>
  /// JSON反序列化
  /// </summary>
  public static T JsonDeserialize<T>(string jsonString)
  {
   //将"yyyy-MM-dd HHmmss"格式的字符串转为"\/Date(1294499956278+0800)\/"格式
   string p = @"\d{4}-\d{2}-\d{2}\s\d{2}\d{2}\d{2}";
   MatchEvaluator matchEvaluator = new MatchEvaluator(ConvertDateStringToJsonDate);
   Regex reg = new Regex(p);
   jsonString = regReplace(jsonString, matchEvaluator);
   DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));
   MemoryStream ms = new MemoryStream(EncodingUTFGetBytes(jsonString));
   T obj = (T)serReadObject(ms);
   return obj;
  }
 
  /// <summary>
  /// 将Json序列化的时间由/Date(1294499956278+0800)转为字符串
  /// </summary>
  private static string ConvertJsonDateToDateString(Match m)
  {
   string result = stringEmpty;
   DateTime dt = new DateTime(1970,1,1);
   dt = dtAddMilliseconds(longParse(mGroups[1]Value));
   dt = dtToLocalTime();
   result = dtToString("yyyy-MM-dd HHmmss");
   return result;
  }
 
  /// <summary>
  /// 将时间字符串转为Json时间
  /// </summary>
  private static string ConvertDateStringToJsonDate(Match m)
  {
   string result = stringEmpty;
   DateTime dt = DateTimeParse(mGroups[0]Value);
   dt = dtToUniversalTime();
   TimeSpan ts = dt - DateTimeParse("1970-01-01");
   result = stringFormat("\\/Date({0}+0800)\\/",tsTotalMilliseconds);
   return result;
  }
 }

  Person p = new Person();
 p.Name = "张三";
 p.Age = 28;
 p.LastLoginTime = DateTime.Now; 
 string jsonString = JsonHelper.JsonSerializer<Person>(p);

{"Age":28,"LastLoginTime":"2011-01-09 01:00:56","Name":"张三"}

string json = "{\"Age\":28,\"LastLoginTime\":\"2011-01-09 00:30:00\",\"Name\":\"张三\"}";
p=JsonHelper.JsonDeserialize<Person>(json);

 function ChangeDateFormat(jsondate) {
  jsondate = jsondate.replace("/Date(", "").replace(")/", "");
  if (jsondate.indexOf("+") > 0) {
   jsondate = jsondate.substring(0, jsondate.indexOf("+"));
  }
  else if (jsondate.indexOf("-") > 0) {
   jsondate = jsondate.substring(0, jsondate.indexOf("-"));
  }
  
  var date = new Date(parseInt(jsondate, 10));
  var month = date.getMonth() + 1 < 10 ? "0" + (date.getMonth() + 1) date.getMonth() + 1;
  var currentDate = date.getDate() < 10 ? "0" + date.getDate() date.getDate();
  return date.getFullYear() + "-" + month + "-" + currentDate;
 }

  List<Person> list = new List<Person>()
 {
  new Person(){ Name="张三", Age=28},
  new Person(){ Name="李四", Age=25}
 };
string jsonString = JsonHelper.JsonSerializer<List<Person>>(list);

"[{\"Age\":28,\"Name\":\"张三\"},{\"Age\":25,\"Name\":\"李四\"}]"

  Dictionary<string, string> dic = new Dictionary<string, string>();
 dic.Add("Name", "张三");
 dic.Add("Age", "28");
 string jsonString = JsonHelper.JsonSerializer < Dictionary<string, string>>(dic);

 "[{\"Key\":\"Name\",\"Value\":\"张三\"},{\"Key\":\"Age\",\"Value\":\"28\"}]"