Inconsistent accessibility: base class is less accessible than class

Question

So I have an abstract base class in a DLL and child classes of that class. I want the childs to be public, but the base to be private so that it cannot be accessed outside of the dll.

How do I do that?

Answer 1

You don't and you can't.

If you want to expose the class as public, the base-type must be public. One other option is to have a public interface, and only expose the type via the interface (presumably with a factory method somewhere for creating instances).

One final option is to encapsulate the base-class rather than inherit it.

Answer 2

Make it public, make all constructors internal (if you're using the default constructor, add a parameterless constructor to override that).

Then while public and not sealed, it can't be sub-classed by external code.

Answer 3

Just to clarify what I was saying in comments on @Marc Gravel's answer you could

public ChildClass : ParentClass
{

}

public ParentClass
{
   internal void MethodIdontWantToExpose()
  {

  }

}

That said an interface is probably the best solution