C# Cast a type to a different type with same declaration

Question

So let's say I have a type X which is an abstract class, like so public abstract class X. Now let's say i have a type A which derives from type Y, like this public class A : Y. Both X and Y have the same definition:

public abstract class X
{
    public string Name { get; internal set; }

    public virtual void PrintName()
    {
        Console.WriteLine(Name);
    }
}

public abstract class Y
{
    public string Name { get; internal set; }

    public virtual void PrintName()
    {
        Console.WriteLine(Name);
    }
}

I can't change anything inside X (Add interface, ...). Also I can not derive from X because a program would automatically load it. The classes X and Y are bigger with fields, properties and a load of methods, but I kept it as minimal, as possible. Is it possible to convert A into X ? Something like

X obj = (X)(new A())

I have already tried: Json De/Seriliazation, using dynamic X cls = (X)(new A() as dynamic);. I probably could use a TypeBuilder, but I don't have any experience using TypeBuilder.

Answer 1

I think you could solve this problem by using AutoMapper: https://docs.automapper.org/en/stable/Mapping-inheritance.html

After adding the AutoMapper nuget package to your project, add the following class:

public class XYBAProfile : AutoMapper.Profile
{
    public XYBAProfile()
    {
        CreateMap<Y, X>()
            .Include<A, B>();
        CreateMap<A, B>();
    }
}

Now you should be able to create the X object from any A object:

 public static void Test()
 {
    var mapperConfig = new AutoMapper.MapperConfiguration(conf => conf.AddProfile<XYBAProfile>());
    var mapper = mapperConfig.CreateMapper();

    var a = new A() { Name = "Something" };
    X x = mapper.Map<X>(a);

    x.PrintName();
 }