c# - 按类型属性继承 XML 反序列化

Question

我有看起来像这样的 XML：

<root>
    <base type="a">
        <common>1</common>
        <concreteA>one</concreteA>
    </base>
    <base type="b">
        <common>2</common>
        <concreteB>two</concreteB>
    </base>
</root>

像这样的类：

public class Root
{
    public List<Base> Bases { get; set; }
}

public class Base
{
    public int Common { get; set; }
}

public class A : Base
{
    public string ConcreteA { get; set; }
}

public class B : Base
{
    public string ConcreteB { get; set; }
}

如何将其反序列化为对象？我已经看过很多关于如何在每个基本节点使用不同名称时如何做到这一点的帖子XmlArrayItemAttribute( ElementName, Type )]，但我需要根据 elementstype属性来选择它。

Answer 1

这是一种非常基本的方法，但我认为它有效。我认为如果类类型是元素而不是属性，那么您应该能够以声明方式解析它。

代码基本上打开类型属性顶部确定要创建的子类，然后手动填充具体属性和公共属性。

[System.Xml.Serialization.XmlType("base")]
public class Base
{
    [System.Xml.Serialization.XmlElement("common")]
    public int Common { get; set; }
}

public class A : Base
{
    public string ConcreteA { get; set; }
}

public class B : Base
{
    public string ConcreteB { get; set; }
}

[System.Xml.Serialization.XmlRootAttribute("root")]
public class Root : System.Xml.Serialization.IXmlSerializable
{
    [System.Xml.Serialization.XmlElement("base")]
    public List<Base> Bases { get; set; }

     public System.Xml.Schema.XmlSchema GetSchema()
    {
        return null;
    }

    public void ReadXml(XmlReader reader)
    {
        this.Bases = new List<Base>();
        var document = XDocument.Load(reader);

        foreach (var element in document.Root.Elements())
        {
            Base baseElement = null;

            var attr = element.Attribute("type");

            if(attr.Value == "a")
            {
                var a = new A();
                a.ConcreteA = element.Element("concreteA").Value;
                baseElement = a;
            }
            else
            {
                var b = new B();
                b.ConcreteB = element.Element("concreteB").Value;
                baseElement = b;
            }

            baseElement.Common = int.Parse(element.Element("common").Value);
            this.Bases.Add(baseElement);
        }

        this.Bases.Dump();
    }

    public void WriteXml(XmlWriter writer)
    {
        throw new NotSupportedException();
    }
}

void Main()
{
    var xmlString = @"<root>
    <base type=""a"">
        <common>1</common>
        <concreteA>one</concreteA>
    </base>
    <base type=""b"">
        <common>2</common>
        <concreteB>two</concreteB>
    </base>
</root>";

    var stream = new StringReader(xmlString);
    var deserializer = new System.Xml.Serialization.XmlSerializer(typeof(Root));
    var result = (Root)deserializer.Deserialize(stream);    
}