覆盖 XML 反序列化以使用基本反序列化并添加功能

Question

我有一个应该被序列化和反序列化的类。

但是每次反序列化后我都需要调用一个同步引用的方法。

无论如何我可以实现反序列化并使用传统的反序列化，但在常规反序列化之后添加对我的方法的调用？

Answer 1

using System.Xml.Serialization;

namespace Custom.Xml.Serialization
{
    public interface IXmlDeserializationCallback
    {
        void OnXmlDeserialization(object sender);
    }

    public class CustomXmlSerializer : XmlSerializer
    {
        protected override object Deserialize(XmlSerializationReader reader)
        {
            var result = base.Deserialize(reader);

            var deserializedCallback = result as IXmlDeserializationCallback;
            if (deserializedCallback != null)
            {
                deserializedCallback.OnXmlDeserialization(this);
            }

            return result;
        }
    }
}

从 IXmlDeserializationCallback 继承您的类并在 OnXmlDeserialization 方法中实现您的同步逻辑。

感谢How do you find out when you've been loaded via XML Serialization?

更新：

好吧，据我了解topicstarter，他不想在每次XML反序列化之后“手动”调用一些逻辑。所以不要这样做：

public class MyEntity
{
     public string SomeData { get; set; }

     public void FixReferences()
     {
          // call after deserialization
          // ...
     }
}

foreach (var xmlData in xmlArray)
{
    var xmlSer = new XmlSerializer(typeof(MyEntity));
    using (var memStream = new MemoryStream(Encoding.UTF8.GetBytes(xmlData)))
    {
       var entity = (MyEntity)xmlSer.Deserialize(memStream);
       entity.FixReferences();

       // do something else with the entity
       // ...  
    }
}

他只想做反序列化，而不用担心额外的调用。在这种情况下，建议的解决方案是最干净/最简单的 - 您只需从 IXmlDeserializationCallback 接口继承您的实体类，并将 XmlSerializer 替换为 CustomXmlSerializer：

 public class MyEntity: IXmlDeserializationCallback
    {
         public string SomeData { get; set; }

         private void FixReferences()
         {
              // call after deserialization
              // ...
         }

         public void OnXmlDeserialization(object sender)
         {
             FixReferences();
         } 
    }

    foreach (var xmlData in xmlArray)
    {
        var xmlSer = new CustomXmlSerializer(typeof(MyEntity));
        using (var memStream = new MemoryStream(Encoding.UTF8.GetBytes(xmlData)))
        {
           var entity = (MyEntity)xmlSer.Deserialize(memStream);
           // entity.FixReferences(); - will be called automatically

           // do something else with the entity
           // ...  
        }
    }

Answer 2

我有一个很好的解决方案 4 u

编写这个静态类

public delegate void OnDeserializedEventArgs(object itemDeserialized, string xmlSource);
public delegate void OnDeserializedFailedEventArgs(string xmlSource);
public static class SerializationServices
{
    public static event OnDeserializedEventArgs OnDeserializedEvent;
    public static event OnDeserializedFailedEventArgs OnDeserializedFailedEvent;

    public static T Deserialize<T>(this string item) where T : class
    {
        XmlSerializer ser = new XmlSerializer(item.GetType());
        StringReader sr = new StringReader(item);
        var obj = ser.Deserialize(sr);

        if (obj is T)
        {
            if (OnDeserializedEvent != null)
                OnDeserializedEvent(obj, item);

            return obj as T;
        }

        if (OnDeserializedFailedEvent != null)
            OnDeserializedFailedEvent(item);

        //callback - invalid event
        return null;
    }
}

然后在这段代码中使用它

public class MyDesrializedClass
{
    //put some properties here...
}
class Program
{
    static void Main(string[] args)
    {
        SerializationServices.OnDeserializedEvent += SerializationServices_OnDeserializedEvent;
        SerializationServices.OnDeserializedFailedEvent += SerializationServices_OnDeserializedFailedEvent;

        string someXml = string.Empty; //replace this with something...
        MyDesrializedClass deserializedClass = someXml.Deserialize<MyDesrializedClass>();
    }

    private static void SerializationServices_OnDeserializedFailedEvent(string xmlSource)
    {
        //will get here before 'deserializedClass' will get it's results
    }

    private static void SerializationServices_OnDeserializedEvent(object itemDeserialized, string xmlSource)
    {
        //will get here before 'deserializedClass' will get it's results
    }
}

如果您将这些代码粘贴到不同的命名空间中，请不要忘记添加“使用 ...”，否则您将不会在程序上下文中看到反序列化方法

扎希

Answer 3

您使用 XmlSerializer 的选项有限。

• 反序列化整个对象图，然后应用您需要的任何修复。
• 在对象的属性设置器中进行一些处理。
• 在您的类型上实现IXmlSerializable，以便您可以显式控制序列化/反序列化。这不是一个简单的选择。

如果您可以改用DataContractSerializer，它有其优点（和缺点），那么您可以使用OnDeserializedAttribute。例如

[DataContract]
public class MyClass
{
    [DataMember]
    public string AMember{get;set;}

    [OnDeserialized]
    public void OnDeserialized(StreamingContext context)
    {
        // called after deserializing instance of MyClass
    }
}