DataContractJsonSerializer serializer = new DataContractJsonSerializer(item.GetType());

            using (MemoryStream ms = new MemoryStream())
            {

                serializer.WriteObject(ms, item);

                StringBuilder sb = new StringBuilder();

                sb.Append(Encoding.UTF8.GetString(ms.ToArray()));

                return sb.ToString();

            }

        }

        /// <summary>
        /// Json反序列化,用于接收客户端Json后生成对应的对象
        /// </summary>
        public static T FromJsonTo<T>(this string jsonString)
        {

            DataContractJsonSerializer ser = new DataContractJsonSerializer(typeof(T));

            MemoryStream ms = new MemoryStream(Encoding.UTF8.GetBytes(jsonString));

            T jsonObject = (T)ser.ReadObject(ms);

            ms.Close();

            return jsonObject;

        }