ISerializable documentation claims it works with XmlSerializer

[MauNguyenVan]

Description

The documentation for ISerializable claims that this interface applies to both binary and XML serialization. In actual fact, the XML Serializer completely ignores this interface. It is actually do nothing with implement of ISerializable and may be binary serialization have the same issuse.

Reproduction Steps

Use .NET 8.0 code from ms docs

[Serializable]
public class MyObject : ISerializable
{
    public int n1;
    public int n2;
    public String str;

    public MyObject()
    {
    }

    protected MyObject(SerializationInfo info, StreamingContext context)
    {
      n1 = info.GetInt32("i");
      n2 = info.GetInt32("j");
      str = info.GetString("k");
    }

    public virtual void GetObjectData(SerializationInfo info, StreamingContext context)
    {
        info.AddValue("i", n1);
        info.AddValue("j", n2);
        info.AddValue("k", str);
    }
}

///in Main

            // Create an instance of your class
            MyObject obj = new MyObject() { n1=1, n2=2, str="str"};

            // XmlSerializer instance
            XmlSerializer serializer = new XmlSerializer(typeof(MyObject));

            // Serialize the object to XML
            using (TextWriter writer = new StreamWriter("serialized.xml"))
            {
                serializer.Serialize(writer, obj);
            }
            // Deserialize the object from XML
            using (XmlReader reader = XmlReader.Create("serialized.xml"))
            {
                MyObject deserializedObj = (MyObject)serializer.Deserialize(reader);

                // Use the deserialized object
                Console.WriteLine($"n1: {deserializedObj.n1}, str: {deserializedObj.str}");
            }

Expected behavior

<?xml version="1.0" encoding="utf-8"?>
<MyObject xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <i>1</i>
  <j>2</k>
  <k>str</k>
</MyObject>

Actual behavior

<?xml version="1.0" encoding="utf-8"?>
<MyObject xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema">
  <n1>1</n1>
  <n2>2</n2>
  <str>str</str>
</MyObject>

Regression?

Use .NET 8.0

Known Workarounds

No response

Configuration

No response

Other information

No response

[StephenMolloy]

The documentation refers to Formatters that use this ISerializable interface - formatters like BinaryFormatter and SoapFormatter. The inclusion of terms like "Xml serialization" in the introduction is a little misleading... but I don't see anywhere in that documentation that specifically references XmlSerializer.

If you need control over the format of data with XmlSerializer, then IXmlSerializable is the interface for that.