using System;

using System.Xml.Serialization;

using System.IO;

​

public interface ISlicable<T>

{

    public abstract T SliceFrom(T b);

}

​

public record B : ISlicable<B>

{       

    public B SliceFrom(B b) => new B(b);

​

    public string BaseProperty

    {

        get;

        set;

    }

}

​

public record C : B

{

    public string SomeProperty

    {

        get;

        set;

    }

}

​

public class Serializer<T> where T: ISlicable<T>

{

    XmlSerializer ser = new XmlSerializer(typeof(B));

    public void Serialize(TextWriter w, T obj) => ser.Serialize(w, obj.SliceFrom(obj));

}

​

public static class Program

{

    static void Main()

    {

        var c = new C{BaseProperty = "Base", SomeProperty = "Some"};

        var serializer = new Serializer<B>();

        TextWriter w = new StringWriter();

        serializer.Serialize(w, c);

        Console.WriteLine(w.ToString());

    }

}