using System;

using System.Globalization;     

using System.Collections.Generic;

using System.Data;

public class Program

{

    public static void Main()

    {

        List<Parent<IParent>> parentList = new List<Parent<IParent>>();

​

        parentList.Add(new Child1());

        parentList.Add(new Child2());    

        parentList[0].parentMethod("Child 1 says Hi!");     

        parentList[1].parentMethod("Child 2 says Hello!");

        ((Child1)parentList[0]).methodOfChild();        

        ((Child2)parentList[1]).methodOfChild();

    }

}

public class Parent<T> 

{   

    public void parentMethod(string msgFromChild)

    {

        Console.WriteLine("Inside Parent, msg from child:" + msgFromChild);     

    }

}

public interface IParent

{ 

    void methodOfChild();

}

​

public class Child1 : Parent<IParent>, IParent

{ 

    public void methodOfChild()

    {

        Console.WriteLine("Inside child 1");        

    }

}

​

public class Child2 : Parent<IParent>, IParent

{ 

    public void methodOfChild()

    {

        Console.WriteLine("Inside child 2");        

    }

}