Force subclasses of an interface to implement ToString

Question

Say I have an interface IFoo and I want all subclasses of IFoo to override Object's ToString method. Is this possible?

Simply adding the method signature to IFoo as such doesn't work:

interface IFoo {     String ToString(); } 

since all the subclasses extend Object and provide an implementation that way, so the compiler doesn't complain about it. Any suggestions?

Answer 1

I don't believe you can do it with an interface. You can use an abstract base class though:

public abstract class Base {     public abstract override string ToString();  } 

Answer 2

abstract class Foo {     public override abstract string ToString(); }  class Bar : Foo {     // need to override ToString() }