XML文本的序列化與反序列化的操作，與遇到的問題

今天遇到了一個XML 反序列化的問題，我使用的C#編程，序列化和反序列化的操作很簡單，代碼如下：

反序列  XML 轉 Object

        //Xml To Object  
        public static T Deserializer(string XML)
        {
            try
            {
                if (string.IsNullOrEmpty(XML))
                {
                    return default(T);
                }
                var stream = new System.IO.StringReader(XML);
                System.Xml.Serialization.XmlSerializer xml = new System.Xml.Serialization.XmlSerializer(typeof(T));
                //序列化對象
                //xmlfile.Close();
                T t = (T)xml.Deserialize(stream);
                return t;
            }
            catch (InvalidOperationException)
            {
                throw;
            }
            catch (System.IO.FileNotFoundException)
            { throw; }
            finally
            {

            }
        }
        
        
        
         //Object To XML 
         public static string Serializer(object obj)
         {
          FileStream xmlfile = new FileStream();
          string XMLString= null;
          
          //創建序列化對象 
          XmlSerializer xml = new XmlSerializer(typeof(T));
          try
          {    //序列化對象
              xml.Serialize(xmlfile, obj);
              StreamReader reader = new StreamReader(xmlfile);
              XMLString = reader.ReadToEnd();
              xmlfile.Close();
          }
          catch (InvalidOperationException)
          {
              throw;
          }
          
          return XMLString;
         }
        
        
        
        
        //Xml To Object 從本地文件讀取
         public static bool Serializer(object obj, string path)
         {
          FileStream xmlfile = new FileStream(path, FileMode.OpenOrCreate);
          
          //創建序列化對象 
          XmlSerializer xml = new XmlSerializer(typeof(T));
          try
          {    //序列化對象
              xml.Serialize(xmlfile, obj);
              xmlfile.Close();
          }
          catch (InvalidOperationException)
          {
              throw;
          }
          
          return true;
          
         }
        
        
        
        //Object To XML 直接寫到本地文件
         public static bool Serializer(object obj, string path)
         {
          FileStream xmlfile = new FileStream(path, FileMode.OpenOrCreate);
          
          //創建序列化對象 
          XmlSerializer xml = new XmlSerializer(typeof(T));
          try
          {    //序列化對象
              xml.Serialize(xmlfile, obj);
              xmlfile.Close();
          }
          catch (InvalidOperationException)
          {
              throw;
          }
          
          return true;
          
         }

然而轉換成Object時報了 錯，異常如下

There is an error in XML document (1, 2). ---> System.InvalidOperationException: was not expected. at Microsoft.Xml.Serialization.GeneratedAssembly.XmlSerializationReaderData.Read5_data()

其實是和返回的Object有關係，在Object頭加上一個特性，如下：

[XmlRoot("xml"), XmlType("xml")]
public class xmlstring {...}

注意：這兩個屬性的值對應的是XML文本的根節點的標籤，如我上面的這個類只能轉化如下標準的XML

<xml>
<id></id>
................................
</xml>

詳細參照：https://stackoverflow.com/questions/4884383/error-deserializing-xml-to-object-xmlns-was-not-expected