如何为 IXmlSerialized 类型添加命名空间前缀

我有以下类定义

[XmlRoot(ElementName = "person",Namespace = "MyNamespace")]
public class Person : IXmlSerializable
{
    public string FirstName { get; set; }
    [XmlNamespaceDeclarations]
    public XmlSerializerNamespaces Namespaces
    {
        get
        {
            var xmlSerializerNamespaces = new XmlSerializerNamespaces();
            xmlSerializerNamespaces.Add("My", "MyNamespace");
            return xmlSerializerNamespaces;
        }
    }

    public string LastName { get; set; }

    public XmlSchema GetSchema()
    {
        return null;
    }

    /// <exception cref="NotSupportedException"/>
    public void ReadXml(XmlReader reader)
    {
        throw new NotSupportedException();
    }

    public void WriteXml(XmlWriter writer)
    {
        writer.WriteElementString("firstName",FirstName);
        writer.WriteElementString("lastName", LastName);
    }
}

我想将其序列化My:MyNamespace 的前缀，所以当我调用代码时

var xmlSerializer = new XmlSerializer(typeof(Person));
var person = new Person
            { FirstName = "John",LastName = "Doe"};            
xmlSerializer.Serialize(Console.Out, person, person.Namespaces);

我期望以下输出：

<?xml version="1.0" encoding="ibm850"?>
<My:person xmlns:My="MyNamespace">
    <My:firstName>John</My:firstName>
    <My:lastName>Doe</My:lastName>
</My:person>

但我得到以下输出：

<?xml version="1.0" encoding="ibm850"?>
<person xmlns="MyNamespace">
  <firstName>John</firstName>
  <lastName>Doe</lastName>
</person>

我知道当我使用时编写前缀是有效的可序列化属性属性并且不继承自IXml可序列化，但我的项目中的类要复杂得多，我无法使用默认的 XmlSerializer。

The XmlSerializertype 不提供任何现成的东西来处理这个问题。
如果你确实需要使用XmlSerializer，你最终会得到一个定制的XmlSerializer实施，还不太开放扩展。因此，下面的实现更多的是一个概念证明，只是为了给您一个想法或一个起点。
为了简洁起见，我省略了任何错误处理，只关注Person你的问题中的班级。仍然需要做一些工作来处理任何嵌套的复杂属性。

As the Serialize方法不是virtual我们必须跟踪他们。主要思想是将所有重载定向到具有自定义实现的单个重载。

由于定制，我们必须在Person在通过指定要应用的 xml 命名空间为其属性编写 xml 元素时，可以使用 xml 来定义类。

下面的代码

PrefixedXmlSerializer xmlSerializer = new PrefixedXmlSerializer(typeof(Person));
Person person = new Person { 
    FirstName = "John", 
    LastName = "Doe" 
    };
xmlSerializer.Serialize(Console.Out, person, person.Namespaces);

结果是

<My:person xmlns:My="MyNamespace">
    <My:firstName>John</My:firstName>
    <My:lastName>Doe</My:lastName>
</My:person>

由你来考虑这一切是否可以接受。
到底，<My:person xmlns:My="MyNamespace"> equals <person xmlns="MyNamespace">.

Person

[XmlRoot(ElementName = "person", Namespace = NAMESPACE)]
public class Person : IXmlSerializable
{
    private const string NAMESPACE = "MyNamespace";

    public string FirstName { get; set; }

    [XmlNamespaceDeclarations]
    public XmlSerializerNamespaces Namespaces
    {
        get
        {
            var xmlSerializerNamespaces = new XmlSerializerNamespaces();
            xmlSerializerNamespaces.Add("My", NAMESPACE);                
            return xmlSerializerNamespaces;
        }
    }

    public string LastName { get; set; }

    public XmlSchema GetSchema()
    {
        return null;
    }

    /// <exception cref="NotSupportedException"/>
    public void ReadXml(XmlReader reader)
    {
        throw new NotSupportedException();
    }   

    public void WriteXml(XmlWriter writer)
    {
        // Specify the xml namespace.
        writer.WriteElementString("firstName", NAMESPACE, FirstName);
        writer.WriteElementString("lastName", NAMESPACE, LastName);
    }
}

带前缀的 XmlSerializer

public class PrefixedXmlSerializer : XmlSerializer
{
    XmlRootAttribute _xmlRootAttribute;


    public PrefixedXmlSerializer(Type type) : base(type)
    {
        this._xmlRootAttribute = type.GetCustomAttribute<XmlRootAttribute>();        
    }


    public new void Serialize(TextWriter textWriter, Object o, XmlSerializerNamespaces namespaces)
    {
        // Out-of-the-box implementation.
        XmlTextWriter xmlTextWriter = new XmlTextWriter(textWriter);
        xmlTextWriter.Formatting = Formatting.Indented;
        xmlTextWriter.Indentation = 2;

        // Call the shadowed version. 
        this.Serialize(xmlTextWriter, o, namespaces, null, null);
    }


    public new void Serialize(XmlWriter xmlWriter, Object o, XmlSerializerNamespaces namespaces, String encodingStyle, String id)
    {
        // Lookup the xml namespace and prefix to apply.
        XmlQualifiedName[] xmlNamespaces = namespaces.ToArray();                                
        XmlQualifiedName xmlRootNamespace =
            xmlNamespaces
                .Where(ns => ns.Namespace == this._xmlRootAttribute.Namespace)
                .FirstOrDefault();

        // Write the prefixed root element with its xml namespace declaration.
        xmlWriter.WriteStartElement(xmlRootNamespace.Name, this._xmlRootAttribute.ElementName, xmlRootNamespace.Namespace);            

        // Write the xml namespaces; duplicates will be taken care of automatically.
        foreach (XmlQualifiedName xmlNamespace in xmlNamespaces)
        {
            xmlWriter.WriteAttributeString("xmlns", xmlNamespace.Name , null, xmlNamespace.Namespace);
        }

        // Write the actual object xml.
        ((IXmlSerializable)o).WriteXml(xmlWriter);

        xmlWriter.WriteEndElement();       
    }
}