对象转JSON

         /// <summary>
         /// 把对象序列化 JSON 字符串
         /// </summary>
         /// <typeparam name="T">对象类型</typeparam>
         /// <param name="obj">对象实体</param>
         /// <returns>JSON字符串</returns>
         public static string GetJson<T>(T obj)
         {
             //记住 添加引用 System.ServiceModel.Web
             /**
              * 如果不添加上面的引用,System.Runtime.Serialization.Json; Json是出不来的哦
              * */
             DataContractJsonSerializer json = new DataContractJsonSerializer(typeof(T));
             using (MemoryStream ms = new MemoryStream())
             {
                 json.WriteObject(ms, obj);
                 string szJson = Encoding.UTF8.GetString(ms.ToArray());
                 return szJson;
             }
         }