反序列化派生 class 时出现 XmlSerializer 异常（<Derived xmlns=''> 不是预期的）

Question

我正在尝试使用 XmlSerializer 序列化和反序列化类的层次结构。序列化工作正常，但是当我尝试反序列化时出现此异常：

System.InvalidOperationException: There is an error in XML document (2, 2). ---> System.InvalidOperationException: <Derived xmlns=''> was not expected.

这是我要反序列化的 xml：

<?xml version="1.0"?>
<Derived xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <BaseStr>Base</BaseStr>
  <DerivedStr>Derived</DerivedStr>
</Derived>

这是我正在使用的代码：

using System;
using System.IO;
using System.Text;
using System.Xml;
using System.Xml.Serialization;

[XmlInclude(typeof(Derived))]
public abstract class Base 
{
    public string BaseStr { get; set; }
}

public class Derived : Base
{
    public string DerivedStr { get; set; }
}

class Program
{
    static void Main(string[] args)
    {
        try
        {
            XmlSerializer serializer = new XmlSerializer(typeof(Derived));
            MemoryStream ms = new MemoryStream();
            serializer.Serialize(ms, new Derived() { DerivedStr = "Derived", BaseStr = "Base" });

            Console.WriteLine(Encoding.ASCII.GetChars(ms.ToArray()));

            ms.Position = 0;

            XmlSerializer deserializer = new XmlSerializer(typeof(Base));
            Base b = (Base)deserializer.Deserialize(ms);
            Console.WriteLine(b.GetType().Name);
        }
        catch(Exception ex)
        {
            Console.WriteLine();
            Console.WriteLine(ex.ToString());
        }
    }
}

为什么反序列化不起作用？我怎样才能让它工作？

Answer 1

您正在创建一个 XmlSerializer，期望仅反序列化 Base 个对象。它不希望看到 <Derived> 元素。如果你使用

XmlSerializer deserializer = new XmlSerializer(typeof(Derived));

你没有得到例外。或者，当您 序列化 Derived 的实例时，您可以使用将生成 <Base> 元素的序列化器：

XmlSerializer serializer = new XmlSerializer(typeof(Base));

这仍然会反序列化为 Derived 的实例，因为 XML 将包含

xsi:type="Derived"

基本上你的序列化器和反序列化器需要用相同的类型构造。

反序列化派生 class 时出现 XmlSerializer 异常（<Derived xmlns=''> 不是预期的）

XmlSerializer exception when deserializing derived class (<Derived xmlns=''> was not expected)

c#

serialization

xml-serialization