C# 简单工厂模式

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApp1
{
    class Program
    {                              
        static void Main(string[] args)
        {
            Console.Write("请输入要电脑名称");
            NoteBook noteBook = Factory(Console.ReadLine());
            noteBook.Seyll();
            Console.ReadKey();
        }
        static NoteBook Factory(string str)
        {
            NoteBook noteBook = null;
            switch (str)
            {
                case "戴尔":
                    noteBook = new Dell();
                    break;
                case "雷神":
                    noteBook = new Asus();
                    break;
                default:
                    break;
            }
            return noteBook;

        }
    }
        public abstract class NoteBook
        {
            public abstract void Seyll();
        }
        public class Dell : NoteBook
        {
            public override void Seyll()
            {
                Console.WriteLine("我是戴尔电脑");
            }  
        }
        public class Asus : NoteBook
        {
            public override void Seyll()
            {
                Console.WriteLine("我是华硕电脑");
            }
        }

    }