Internal abstract class: how to hide usage outside assembly?

Question

I have a common assembly/project that has an abstract base class, then several derived classes that I want to make public to other assemblies.

I don\'t want the abs

Answer 1

A way to work around this limitation is to use composition instead of inheritance (there are other good reasons to do this too). For example, instead of:

internal abstract class MyBase
{
    public virtual void F() {}
    public void G() {}
}

public class MyClass : MyBase // error; inconsistent accessibility
{
    public override void F() { base.F(); /* ... */ }
}

Do this:

public interface IMyBase
{
    void F();
}

internal sealed class MyBase2 : IMyBase
{
    public void F() {}
    public void G() {}
}

public sealed class MyClass2 : IMyBase
{
    private readonly MyBase2 _decorated = new MyBase2();
    public void F() { _decorated.F(); /* ... */ }
    public void G() { _decorated.G(); }
}

You can omit the IMyBase interface entirely if the public doesn't need to know about it and your internals don't either.