<responses> 
  <response> 
    <order_serial_no>xfs101100111012</order_serial_no>  
    <mail_no>4060005668136</mail_no>  
    <pdf_info>王志奇gfz</pdf_info>  
    <status>1</status>  
    <msg>更新訂單請使用更新介面</msg> 
  </response> 
</responses>

C#類

    [XmlRoot("responses")]
    public class Responses
    {
        //[XmlElement("response")]
        public YUN_DA_Response response { get; set; }

        public Responses()
        {
            response = new YUN_DA_Response();
        }
    }

    public class YUN_DA_Response
    {
        
 
public string order_serial_no { get; set; }
        public string mail_no { get; set; }
        public string status { get; set; }
        public string msg { get; set; }

        public string pdf_info { get; set; }
    }

轉換：

 /// <summary>
        /// 反序列化
        /// </summary>
        /// <typeparam name="T">
 
實體</typeparam>
        /// <param name="strXml">xml檔案</param>
        /// <returns></returns>
        public T Deserialize<T>(string strXml) where T : class
        {
            try
            {

                object obj;
                using (MemoryStream memoryStream = new MemoryStream(Encoding.UTF8.GetBytes(strXml)))
                {
                    using (XmlReader xmlReader = XmlReader.Create(memoryStream))
                    {
                        XmlSerializer xmlSerializer = new XmlSerializer(typeof(T));
                        obj = xmlSerializer.Deserialize(xmlReader);
                    }
                }
                return obj as T;
            } 
            catch (Exception ex)
            {
                return null;
            }
        }

            string testStr = @"
<responses> 
  <response> 
    <order_serial_no>xfs101100111012</order_serial_no>  
    <mail_no>4060005668136</mail_no>  
    <pdf_info>王志奇gfz</pdf_info>  
    <status>1</status>  
    <msg>更新訂單請使用更新介面</msg> 
  </response> 
</responses>
";

            var _t = Deserialize<Responses>(testStr);