在序列化期间动态控制XML元素名称

这是我要解决的问题：我有一个用于多媒体节目的插件结构，它允许通过从我的框架中的基类进行子类化来在外部程序集中实现媒体类型。一个节目包含一个媒体类型列表。使用XmlSerializer加载节目并将其保存为XML。这一切都有效，即使插件MediaTypes的程序类型映射也是如此。

但是，我希望能够加载包含未知的MediaTypes的XML文件，因为插件不可用。

举例来说，这里有这样一个XML文件：

<MultiMediaShow>
    <MediaTypes>
        <SomeType />
        <SomeType />
        <AnotherType />
        <UnknownTypeFromPluginNotLoaded />
    </MediaTypes> 
</MultiMediaShow>

在上面的例子中，我假设2个"已知"的媒体类型SomeType和AnotherType，由2个插件程序集混合而成。第三种类型(UnknownTypeFromPluginNotLoaded(未知。

我已经能够反序列化这样的未知对象，但在序列化方面很吃力。在我的应用程序中，到目前为止我有以下代码：

// To be implemented / subclassed by plugin assembly types
public abstract class MediaType
{
}
public class UnknownMediaType : MediaType 
{
    [XmlAnyElement]
    public XmlElement[] UnknownChildElements;
    [XmlAnyAttribute]
    public XmlAttibute[] UnknownAttributes;
    [XmlIgnore]
    public string XmlTagName;   // stores the xml element tag name in the original document
}
[XmlRoot("MultimediaShow")]
public class MultimediaShow
{
    public List<MediaType> MediaTypes = new List<MediaType>();
}

当用XmlSerializer反序列化时，我使用事件UnknownElement并手动将UnknownMediaType元素插入show.MediaTypes:

void HandleUnknownElements(Show show, List<XmlElementEventArgs> unknownElementEvents, XmlAttributeOverrides overrides)
{
    // add a root attribute to UnknownMediaType
    XmlAttributes attrs = new XmlAttributes();
    XmlRootAttribute xmlRoot = new XmlRootAttribute(e.Element.Name);
    attrs.XmlRoot = xmlRoot;
    XmlAttributeOverrides o = new XmlAttributeOverrides();
    o.Add(typeof(UnknownMediaObject), attrs);
    // use a new XmlSerializer and a memory stream for deserializting the object as UnknownMediaType.
    XmlSerializer xmlSerializer = new XmlSerializer(typeof(UnknownMediaType), o);
    using (MemoryStream memoryStream = new MemoryStream())
    {
        XmlDocument doc = new XmlDocument();
        doc.AppendChild(doc.ImportNode(e.Element, true));
        doc.Save(memoryStream);
        memoryStream.Position = 0;
        try
        {
            // deserialize the object, store the XML element name and insert it into the chapter
            UnknownMediaType t = xmlSerializer.Deserialize(memoryStream) as UnknownMediaObject;
            t.XmlTagName = e.Element.Name;
            show.MediaTypes.Add(t);
        }
        catch (Exception exc)
        {
            System.Diagnostics.Debug.WriteLine(exc.ToString());
            //return objectType.IsByRef ? null : Activator.CreateInstance(objectType);
        }
    }
}

BIG BIG的问题是，在序列化对象时，这样的事件似乎不可用。我得到的输出(不是很令人惊讶(是：

<MultiMediaShow>
    <MediaTypes>
        <SomeType />
        <SomeType />
        <AnotherType /> 
        <UnknownMediaType />    // !!!! was 'UnknownTypeFromPluginNotLoaded' !!!!
    </MediaTypes> 
</MultiMediaShow>

然而，这显然与我反序列化的内容不同。所以问题是，我该如何最好地解决这个问题？！？！

非常感谢所有的帮助！！

干杯，Felix

---

更新

我想知道是否可以通过编程生成从UnknownMediaType派生的类，并且类名取自UnknownMediaType.XmlTagName。或者，有一个用于指定类的XML标记名的属性？？

干杯，Felix

    void HandleUnknownElements(Show show, List<XmlElementEventArgs> unknownElementEvents, XmlAttributeOverrides overrides)
    {
        foreach (XmlElementEventArgs e in unknownElementEvents)
        {
            // (1) Dynamically create a type that simply inherits from UnknownMediaType 
            AssemblyName assName = new AssemblyName("Show Dynamic Type " + e.Element.Name + " Assembly");
            AssemblyBuilder assBuilder = AppDomain.CurrentDomain.DefineDynamicAssembly(assName, AssemblyBuilderAccess.Run);
            ModuleBuilder modBuilder = assBuilder.DefineDynamicModule(assBuilder.GetName().Name);
            TypeBuilder typeBuilder = modBuilder.DefineType(e.Element.Name, TypeAttributes.Class | TypeAttributes.Public, typeof(UnknownMediaType));
            Type objectType = typeBuilder.CreateType();

            // (2) Add a root attribute to the type as override
            XmlAttributes attrs = new XmlAttributes();
            XmlRootAttribute xmlRoot = new XmlRootAttribute(e.Element.Name);
            attrs.XmlRoot = xmlRoot;
            XmlAttributeOverrides o = new XmlAttributeOverrides();
            o.Add(objectType, attrs);

            // (3) Use a memory stream for creating a temporary XML document that will be deserialized
            using (MemoryStream memoryStream = new MemoryStream())
            {
                XmlDocument doc = new XmlDocument();
                doc.AppendChild(doc.ImportNode(e.Element, true));
                doc.Save(memoryStream);
                memoryStream.Position = 0;

                // (4) Deserialize the object using an XmlSerializer and add it
                try
                {
                    XmlSerializer xmlSerializer = new XmlSerializer(objectType, o);
                    UnknownMediaType t = xmlSerializer.Deserialize(memoryStream) as UnknownMediaType;
                    show.MediaTypes.Add(t);
                }
                catch (Exception exc)
                {
                    System.Diagnostics.Debug.WriteLine(exc.ToString());
                }
            }
        }
    }