Interfaces - Implement abstract class methods

Question

I'm not exactly sure how to ask this question, but basically what I want to do is access the abstract methods from IDog. Consider this:

    static void Main(string[] args)
    {
        IDog dog = new Dog();
        dog.CatchFrisbee();
        dog.Speak("Bark") // error -> no implementation
        Console.ReadLine();
    }

    public class Dog : Animal, IDog
    {
        public void CatchFrisbee()
        {
            Console.WriteLine("Dog Catching Frisbee");
        }
    }
    public abstract class Animal : IAnimal
    {
        public void Speak(string sayWhat)
        {
            Console.WriteLine(sayWhat);
        }

        public void Die()
        {
            Console.WriteLine("No Longer Exists");
        }
    }
    public interface IDog
    {
        void CatchFrisbee();
    }
    public interface IAnimal
    {
        void Die();

        void Speak(string sayWhat);
    }

From my static void Main, I would like to be able to call dog.Speak() but I can't because it's not implemented in IDog. I know I can easily access Speak() from my derived classes but is it possible to access it from the implemenation or would that be a bad design?

Answer 1

假设所有IDog都是IAnimal ， IDog IAnimal声明为实现IAnimal

public interface IDog : IAnimal

Answer 2

You could perform a cast:

 ((Animal) dog).Speak("Bark"); 

Or take advantage of multiple interface inheritance:

public interface IDog : IAnimal
{
    void CatchFrisbee();
}