using System;

​

interface Base

{

    //public readonly string Test = "Base.Test";

    string Test

    {

        get;

    }

//public void Show()

//{

//    Console.WriteLine("Base.Test: {0}", Test);

//}

}

​

class Child : Base

{

    public string Test

    {

        get;

        private set;

    }

​

    public void Initialize(string t)

    {

        Test = t;

    }

}

​

static class BaseExtensions

{

    public static void Show(this Base b, string arg2)

    {

        Console.WriteLine("Base.Test: {0}", b.Test);

    }

}

​

public class Program

{

    public static void Main(string[] args)

    {

        Child Fero = new Child();

        Fero.Initialize("Fero.Initialize");

        Fero.Show("arg2");

    }

}