对象和XML，JSON格式字符串的相互转换

• 对象和Json格式数据互转。这里用到了JSON.NET（Newtonsoft.json）需要应用外部dll，可自行下载
  

          /// <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 ToJsonString<T>(this T obj)
          {
              var json = new DataContractJsonSerializer(typeof(T));
              using (var ms = new MemoryStream())
              {
                  json.WriteObject(ms,obj);
                  string szJson = Encoding.UTF8.GetString(ms.ToArray());
                  return szJson;
              }
          }
  
          /// <summary>
          /// 把JSON字符串还原为对象
          /// </summary>
          /// <typeparam name="T">对象类型</typeparam>
          /// <param name="szJson">JSON字符串</param>
          /// <returns>对象实体</returns>
          public static T ParseFormJson<T>(this string szJson)
          {
              T obj = Activator.CreateInstance<T>();
              using (var ms = new MemoryStream(Encoding.UTF8.GetBytes(szJson)))
              {
                  var dcj = new DataContractJsonSerializer(typeof(T));
                  return (T)dcj.ReadObject(ms);
              }
          }

• 对象和xml格式字符串互转。as作用：强制转换为引用类型，所以T要限制为class。
  

          /// <summary>
          /// 把对象转换为XML字符串
          /// </summary>
          /// <typeparam name="T">对象类型</typeparam>
          /// <param name="obj">对象实体</param>
          /// <returns>xml格式的字符串</returns>
          public static string ToXmlString<T>(this T obj)
          {
              string xmlString;
              var xmlSerializer = new XmlSerializer(typeof(T));
              using (var ms = new MemoryStream())
              {
                  var streamWriter = new StreamWriter(ms);
                  xmlSerializer.Serialize(streamWriter,obj);
  
                  xmlString = Encoding.UTF8.GetString(ms.ToArray());
              }
              return xmlString;
          }
  
          /// <summary>
          /// 把XML格式的字符串还原为对象
          /// </summary>
          /// <typeparam name="T">对象类型</typeparam>
          /// <param name="xml">xml格式字符串</param>
          /// <returns>对象实体</returns>
          public static T XmlToObject<T>(this string xml) where T : class
          {
  
              var xmlSerializer = new XmlSerializer(typeof(T));
              using (var ms = new MemoryStream(Encoding.UTF8.GetBytes(xml)))
              {
                  return xmlSerializer.Deserialize(ms) as T;
              }
          }