using System;

​

public class Program

{

    public static void Main()

    {

        MyClass cls = new MyClass();

        cls.DoSomething();

        IMyInterface inInterface = cls;

        inInterface.DoSomething();

    }

}

​

interface IMyInterface

{

    void DoSomething();

}

​

class MyClass : IMyInterface

{

    public void DoSomething()

    {

        Console.WriteLine("Do Something.");

    }

}

​

​