c# - 如何用派生类序列化基类

Question

.

你好，

我有这个示例代码:

public class Vehicule
{
    public string Name { get; set; }
    public Brand Brand { get; set; }
}
public class Car : Vehicule
{
    public string Matriculation { get; set; }
}



public class Brand
{
    public string Name { get; set; }
}
public class Renault : Brand
{
    public string Information { get; set; }
}

如果我创建这个实例:

var car = new Car { Name = "Clio", Matriculation = "XXX-XXX", Brand = new Renault { Name = "Renault", Information = "Contact Infos" } };

当我像那样序列化这个对象时:

var serializer = new XmlSerializer(typeof(Car), new Type[] { typeof(Renault)});
serializer.Serialize(wr, car);

我得到这个:

<?xml version="1.0" encoding="utf-8"?>
<Car xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Name>Clio</Name>
  <Brand xsi:type="Renault">
    <Name>Renault</Name>
    <Information>Contact Infos</Information>
  </Brand>
  <Matriculation>XXX-XXX</Matriculation>
</Car>

但是，在我的项目中，我不需要关于派生类的信息，我只想要来自这个实例的基类元素，如下所示:

var serializer = new XmlSerializer(typeof(Vehicule));
serializer.Serialize(wr, car);

Xml:

<?xml version="1.0" encoding="utf-8"?>
<Vehicule xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <Name>Clio</Name>
  <Brand>
    <Name>Renault</Name>
  </Brand>
</Vehicule>

你能帮我获得好的Xml(仅限基本类型Vehicule和Brand)吗？

非常感谢

Answer 1

你不能神奇地将派生类序列化为基类，因为

"...Serialization checks type of instance by calling Object.getType() method. This method always returns the exact type of object."

http://bytes.com/topic/net/answers/809946-how-force-serialize-base-type

如果您真的只需要序列化基类，这里的解决方案是实现 IXmlSerializable 接口(interface)并创建您自己的自定义序列化程序。

IXmlSerializable: http://msdn.microsoft.com/en-us/library/system.xml.serialization.ixmlserializable(v=vs.110).aspx

再想一想。如果您可以解决输出额外 XML 元素的限制，则可以通过以下任一方式仅使用基对象序列化派生类:1) 使用 XmlIncludeAttributes在基类上告诉它期望哪些类型或 2) 使用 XmlSerializer constructor采用类型列表的重载。

编辑:稍微考虑一下之后，解决方法是将 Clone() 方法添加到基础对象上，然后序列化基础对象的克隆。

LinqPad 代码:

public class Vehicule
{
    public string Name { get; set; }
    public Brand Brand { get; set; }

    public Vehicule Clone()
    {
        return new Vehicule { Name = this.Name, Brand = new Brand { Name = this.Brand.Name } };
    }
}
public class Car : Vehicule
{
    public string Matriculation { get; set; }
}



public class Brand
{
    public string Name { get; set; }
}
public class Renault : Brand
{
    public string Information { get; set; }
}

void Main()
{   
    var car = new Car { Name = "Clio", Matriculation = "XXX-XXX", Brand = new Renault { Name = "Renault", Information = "Contact Infos" } };
    var vehicle = car as Vehicule;

    var serializer = new System.Xml.Serialization.XmlSerializer(typeof(Vehicule));

    XmlWriterSettings settings = new XmlWriterSettings
    {
        Encoding = new UnicodeEncoding(false, false),
        Indent = false,
        OmitXmlDeclaration = false
    };

    using(StringWriter textWriter = new StringWriter())
    using(XmlWriter xmlWriter = XmlWriter.Create(textWriter, settings)) {
        serializer.Serialize(xmlWriter, vehicle.Clone());
        textWriter.ToString().Dump();
    }
}