SO Question http://stackoverflow.com/questions/39089582/accessing-the-correct-function-in-an-arraylist-of-different-child-classes/39089681#39089684

ParentFooHiding

using System;
using System.Collections;
using System.Collections.Generic;

namespace ConsoleApplication4
{
    class Program
    {
        static void Main(string[] args)
        {
            var children = new List<Parent>();
            children.Add(new Child());
            children[0].Foo();

            ArrayList foos = new ArrayList();
            foos.Add(new Child());
            (foos[0] as Parent).Foo();

            Console.ReadKey();
        }

        public class Parent
        {
            public void Foo()
            {
                Console.WriteLine("I'm the parent");
            }
        }

        public class Child : Parent
        {
            public new void Foo()
            {
                Console.WriteLine("I'm the child");
            }
        }
    }
}