JSON(JavaScript Object Notation, JS 对象标记) 是一种轻量级的数据交换格式。

关于内存对象和JSON字符串的相互转换，在实际项目中应比较广泛，经过一番搜索，找到如下三种方法来解决此问题，分别是使用 Newtonsoft.Json.dll、DataContractJsonSerializer、 JavaScriptSerializer。 

方法一： Newtonsoft.Json.dll 

Newtonsoft.Json.dll在.net2.0之后的版本可以支持 我的版本.net framework4.0

类设计：

class JsonNewtonsoft
    {
        /// <summary>
        /// 把对象转换为JSON字符串
        /// </summary>
        /// <param name="o">对象</param>
        /// <returns>JSON字符串</returns>
        public static string ToJSON(this object o)
        {
            if (o == null)
            {
                return null;
            }
            return JsonConvert.SerializeObject(o);
        }
        /// <summary>
        /// 把Json文本转为实体
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="input"></param>
        /// <returns></returns>
        public static T FromJSON<T>(this string input)
        {
            try
            {
                return JsonConvert.DeserializeObject<T>(input);
            }
            catch (Exception ex)
            {
                return default(T);
            }
        }
    }

方法二：DataContractJsonSerializer

使用这种 需要引用 System.Runtime.Serialization.dll

类设计：

class JsonDataContractJsonSerializer
    {
        /// <summary>
        /// 内存对象转换为json字符串
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public static string ObjectToJson(object obj)
        {
           DataContractJsonSerializer serializer = new DataContractJsonSerializer(obj.GetType());
           MemoryStream stream = new MemoryStream();
           serializer.WriteObject(stream, obj);
           byte[] dataBytes = new byte[stream.Length];
           stream.Position = 0;
           stream.Read(dataBytes, 0, (int)stream.Length);
           return Encoding.UTF8.GetString(dataBytes);
        }
       /// <summary>
       /// Json字符串转内存对象
       /// </summary>
       /// <param name="jsonString"></param>
       /// <param name="obj"></param>
       /// <returns></returns>
        public static object JsonToObject(string jsonString, object obj)
        {
           DataContractJsonSerializer serializer = new DataContractJsonSerializer(obj.GetType());
           MemoryStream mStream = new MemoryStream(Encoding.UTF8.GetBytes(jsonString));
           return serializer.ReadObject(mStream);
        }
    }

方法三：JavaScriptSerializer

需要引用：System.Web.Extensions.dll

类设计：

public static class JsonJavaScriptSerializer
    {
        /// <summary>
        /// 内存对象转换为json字符串
        /// </summary>
        /// <param name="obj"></param>
        /// <returns></returns>
        public static string ToJSON(object obj)
        {
            StringBuilder sb = new StringBuilder();
            JavaScriptSerializer json = new JavaScriptSerializer();
            json.Serialize(obj, sb);
            return sb.ToString();
        }
        /// <summary>
        /// Json字符串转内存对象
        /// </summary>
        /// <param name="jsonString"></param>
        /// <param name="obj"></param>
        /// <returns></returns>
        public static T FromJSON<T>(string jsonString)
        {
            JavaScriptSerializer json = new JavaScriptSerializer();
            return json.Deserialize<T>(jsonString);
        }
 
    }