如何创建序列化对象集C#

您正在尝试使用多态字段序列化和反序列化数据。这里有几个选项:

1. 如果事先知道多态字段中可能遇到的所有类型,可以使用 attributes 告诉 XmlSerializer 如何序列化和反序列化每个类型。特别是,对于多态字段,应用 [XmlElement("DerivedElementName", Type = typeof(DerivedElementType))] 对于可能遇到的每个派生类型。

   例如,简化 RootXml 类,下面允许序列化两种不同类型的报表:

   [XmlRoot("Report", Namespace = "")]
   public class Report
   {
       [XmlAttribute]
       public string Code { get; set; }
   
       [XmlElement]
       public decimal TotalCost { get; set; }
   }
   
   [XmlRoot("DifferentReport", Namespace = "fuuuu")]
   public class DifferentReport
   {
       public DifferentReport() { }
   
       public DifferentReport(string code, string value)
       {
           this.Code = code;
           this.Value = value;
       }
   
       [XmlAttribute]
       public string Code { get; set; }
   
       [XmlText]
       public string Value { get; set; }
   }
   
   [XmlRoot("RootXml", Namespace = "")]
   public class RootXml
   {
       public RootXml() { }
   
       object _test;
   
       [XmlElement("Report", Type=typeof(Report))]
       [XmlElement("DifferentReport", Type = typeof(DifferentReport))]
       public object Data
       {
           get { return _test; }
           set { _test = value; }
       }
   }
   

   之后,可以对以下两项进行序列化和反序列化:

       var root1 = new RootXml { Data = new Report { Code = "a code", TotalCost = (decimal)101.01 } };
       var root2 = new RootXml { Data = new DifferentReport { Code = "a different code", Value = "This is the value of the report" } };
   

   注意,您可以对多态性使用相同的技术 列表 ,在这种情况下,序列化程序将需要具有指定名称的元素序列:

   [XmlRoot("RootXml", Namespace = "")]
   public class RootXml
   {
       public RootXml() { }
   
       List<object> _test;
   
       [XmlElement("Report", Type=typeof(Report))]
       [XmlElement("DifferentReport", Type = typeof(DifferentReport))]
       public List<object> Data
       {
           get { return _test; }
           set { _test = value; }
       }
   }
   

2. 如果XML可以是任何东西,但您不知道它可能包含什么(例如,因为您必须从将来的版本反序列化XML,并在不丢失数据的情况下重新序列化它),则可能需要将XML加载到 XDocument 然后使用Linq to XML手动搜索数据。有关如何执行此操作的信息,请参阅此处: Basic Queries (LINQ to XML) .

3. 您可以采用混合方法,将XML加载到 X文档 ,然后使用 XmlSerializer ,使用以下扩展方法:

   public static class XObjectExtensions
   {
       public static T Deserialize<T>(this XContainer element)
       {
           return element.Deserialize<T>(new XmlSerializer(typeof(T)));
       }
   
       public static T Deserialize<T>(this XContainer element, XmlSerializer serializer)
       {
           using (var reader = element.CreateReader())
           {
               object result = serializer.Deserialize(reader);
               if (result is T)
                   return (T)result;
           }
           return default(T);
       }
   
       public static XElement Serialize<T>(this T obj, bool omitStandardNamespaces = true)
       {
           return obj.Serialize(new XmlSerializer(obj.GetType()), omitStandardNamespaces);
       }
   
       public static XElement Serialize<T>(this T obj, XmlSerializer serializer, bool omitStandardNamespaces = true)
       {
           var doc = new XDocument();
           using (var writer = doc.CreateWriter())
           {
               XmlSerializerNamespaces ns = null;
               if (omitStandardNamespaces)
                   (ns = new XmlSerializerNamespaces()).Add("", ""); // Disable the xmlns:xsi and xmlns:xsd lines.
               serializer.Serialize(writer, obj, ns);
           }
           return doc.Root;
       }
   }
   

   然后使用它们找出并反序列化XML的已知部分,如下所示:

       var doc = XDocument.Parse(xml);
       var reportElement = doc.Root.Element("Report");
       if (reportElement != null)
       {
           var report1 = doc.Root.Element("Report").Deserialize<Report>();
           // Do something with the report.
   
           // Create a different report 
           var differentReport = new DifferentReport { Code = report1.Code + " some more code", Value = "This is the value of the report" };
           var differentElement = differentReport.Serialize();
   
           reportElement.AddAfterSelf(differentElement);
           reportElement.Remove();
       }
   

4. 好的,考虑到您使用的是c#2.0,您可以将Xml加载到 XmlDocument 并按如下所述使用: Process XML Data Using the DOM Model 这是Linq到XML的先驱API,使用起来有点困难,但完全是功能性的。

   您也可以采用混合方法并使用 XmlSerializer 反序列化和重新序列化 XmlDocument 。这里有一些 extension methods 为此目的-- 但由于您使用的是c#2.0 必须 删除 this 关键字 :

   public static class XmlNodeExtensions
   {
       public static XmlElement SerializeToXmlElement<T>(this T o, XmlElement parent)
       {
           return SerializeToXmlElement(o, parent, new XmlSerializer(o.GetType()));
       }
   
       public static XmlElement SerializeToXmlElement<T>(this T o, XmlElement parent, XmlSerializer serializer)
       {
           int oldCount = parent.ChildNodes.Count;
           XPathNavigator navigator = parent.CreateNavigator();
           using (XmlWriter writer = navigator.AppendChild())
           {
               writer.WriteComment(""); // Kludge suggested here: https://social.msdn.microsoft.com/Forums/en-US/9ff20a3c-913d-4c6f-a18a-c10040290862/how-to-xmlserialize-directly-into-xmldocument?forum=asmxandxml
               serializer.Serialize(writer, o);
           }
           XmlElement returnedElement = null;
           for (int i = parent.ChildNodes.Count - 1; i >= oldCount; i--)
           {
               XmlComment comment = parent.ChildNodes[i] as XmlComment;
               if (comment != null)
               {
                   parent.RemoveChild(comment);
               }
               else
               {
                   returnedElement = (parent.ChildNodes[i] as XmlElement) ?? returnedElement;
               }
           }
           return returnedElement;
       }
   
       public static XmlDocument SerializeToXmlDocument<T>(this T o)
       {
           return SerializeToXmlDocument(o, new XmlSerializer(o.GetType()));
       }
   
       public static XmlDocument SerializeToXmlDocument<T>(this T o, XmlSerializer serializer)
       {
           XmlDocument doc = new XmlDocument();
           using (XmlWriter writer = doc.CreateNavigator().AppendChild())
               serializer.Serialize(writer, o);
           return doc;
       }
   
       public static T Deserialize<T>(this XmlElement element)
       {
           return Deserialize<T>(element, new XmlSerializer(typeof(T)));
       }
   
       public static T Deserialize<T>(this XmlElement element, XmlSerializer serializer)
       {
           using (var reader = new XmlNodeReader(element))
               return (T)serializer.Deserialize(reader);
       }
   }
   

   给定这些方法,您可以执行以下操作:

       // Load the document from XML
       XmlDocument doc = new XmlDocument();
       doc.LoadXml(xml);
   
       // Find all nodes with name "Report"
       foreach (XmlElement reportNode in doc.SelectNodes("/RootXml/Report"))
       {
           // Deserialize as a Report
           Report report = XmlNodeExtensions.Deserialize<Report>(reportNode);
           // Do something with it 
   
           // Create a new Report, based on the original report.
           DifferentReport differentReport = new DifferentReport(report.Code + " some more code", "This is the value of the report"); ;
           // Add the new report to the children of RootXml
           XmlElement newNode = XmlNodeExtensions.SerializeToXmlElement(differentReport, (XmlElement)reportNode.ParentNode);
       }
   

   正如您所看到的那样,这与Linq to XML非常相似。