Inheritance design using Interface + abstract class. Good practice?

Question

I\'m not really sure how to title this question but basically I have an interface like this:

public interface IFoo
{
    string ToCMD();
}

a co

Answer 1

you need the interface; you may or may not need the abstract class.

in general, if you can provide some useful behavior in a base class, then provide a base class; if the base class is not complete by itself then make it abstract (MustInherit in VB parlance)

otherwise, the interface is sufficient