method hiding

Program.cs

using System;

namespace ConsoleApp1
{
    class Foo
    {
        public void Do()
        {
            throw new InvalidOperationException();
        }
    }

    class Bar : Foo
    {
        public new void Do()
        {
            Console.WriteLine("Hello World!");
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Foo foo = new Bar();
            foo.Do();
        }
    }
}