Extension methods in a data contract

Question

Can we two WCF services where one service contract derives from another and have an extension method inside the derived contract. what will be the result of accessing this contract from the WCF Client. I.e. what will happen if IDServiceis accessed E.g.

[ServiceContract]
public interface IBaseService
{
  public void A();
  ...
}

[ServiceContract]
public interface IDService: IBaseService
{
  public static void B(this IBaseService S);
  ....
}

Answer 1

You can't define static methods in an interface (nor the access modifier public which you've specified above either).