using System;

using System.Collections.Generic;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var animals = new List<Animal>(){

            new Dog(),

            new Cat()

        };

        var dogs = animals.OfType<Dog>();

        foreach(var dog in animals){

            Console.WriteLine(dog.GetType());

        }

    }

}

​

public class Animal {

   public string name = "aaa";    

}

​

​

public class Dog:Animal{

    public new string name = "ddd";

}

​

public class Cat:Animal{

    public new string name = "mmm";

​

}