XMLSerialization：参数对象“Sw”的类型不是原始的

Question

我正在尝试将对象序列化为 XML 文件，但出现上述错误。

问题似乎出在包含基类列表但由从基类派生的对象填充的对象上。

示例代码如下：

public class myObject
{
    public myObject()
    {
        this.list.Add(new Sw());
    }

    public List<Units> list = new List<Units>();
}

public class Units
{
    public Units()
    {
    }
}

public class Sw : Units
{
    public Sw();
    {
    }

    public void main()
    {
        myObject myObject = new myObject();
        XmlSerializer serializer = new XmlSerializer(typeof(myObject));
        TextWriter textWriter = new StreamWriter ("file.xml");
        serializer.Serialize (textWriter, myObject);
    }

例如仅包含 List<Units> 的对象，该对象由继承自 Units 类 (Sw) 的派生对象填充。

很抱歉没有提供我的实际代码，但所涉及的对象非常复杂，这似乎是对象中唯一无法成功序列化的部分 - 并且仅当列表包含派生类时。

如何正确序列化这样的类？

Answer 1

使用XmlInclude 属性标记Units 类，将派生类作为参数传递：

[XmlInclude(typeof(Sw))]
public class Units
{
    public Units()
    {
    }
}

Answer 2

将对象序列化为 XML。您可以使用以下代码

public String SerializeResponse(SW sw)
{
    try
    {
        String XmlizedString = null;
        XmlSerializer xs = new XmlSerializer(typeof(SW));
        //create an instance of the MemoryStream class since we intend to keep the XML string 
        //in memory instead of saving it to a file.
        MemoryStream memoryStream = new MemoryStream();
        //XmlTextWriter - fast, non-cached, forward-only way of generating streams or files 
        //containing XML data
        XmlTextWriter xmlTextWriter = new XmlTextWriter(memoryStream, Encoding.UTF8);
        //Serialize emp in the xmlTextWriter
        xs.Serialize(xmlTextWriter, sw);
        //Get the BaseStream of the xmlTextWriter in the Memory Stream
        memoryStream = (MemoryStream)xmlTextWriter.BaseStream;
        //Convert to array
        XmlizedString = UTF8ByteArrayToString(memoryStream.ToArray());
        return XmlizedString;
    }
    catch (Exception ex)
    {
        throw;
    }
}

该方法将返回一个 XML 字符串，要实现上述功能，您需要导入以下库：

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