using System;

using System.Collections.Generic;

​

interface A { string MyProp();}

interface B : A { }

​

class AImpl : A

{

    public string MyProp(){return _myProp;}

    private string _myProp;

    public AImpl(string s){_myProp = s;}

}

​

class Test {

    public void TestMethod()

    {

        IList<A> listOfA = new List<A>{new AImpl("B1"), new AImpl("B2")};

        foreach (B b in listOfA)

        {

            Console.WriteLine(b.MyProp());

        }

    }

}

public class Program

{

    public static void Main()

    {

        new Test().TestMethod();

    }

}