.NET基础回顾（三）

1 Person p = new Person();
2 p.SayHi();//调用父类的
3 Student s = new Student();
4 s.SayHi(); //调用子类的
5 //里氏替换原则
6 Person p1 = new Student();
7 P1.SayHi(); //调用父类的

 1 //Person.cs
 2 class Person
 3     {
 4         public virtual void SayHi()
 5         {
 6             Console.WriteLine("我是人。");
 7         }
 8 }
 9 
10 //Chinese.cs
11 class Chinese:Person
12     {
13         public override void SayHi()
14         {
15             Console.WriteLine("我是中国人。");
16         }
17 }
18 
19 //GuangDongRen.cs
20 class GuangDongRen:Chinese
21     {
22         public override void SayHi()
23         {
24             Console.WriteLine("我是广东人。");
25         }
26     }
27 
28 //Main
29 static void Main(string[] args)
30         {
31             Person p = new GuangDongRen();
32             p.SayHi();
33 //输出“广东人”
34             //如果GuangDongRen类里面没有重写SayHi()方法，则输出“中国人”
35 
36             Console.ReadKey();
37         }

 1 //Person.cs
 2 public virtual void WashBody()
 3         {
 4             Console.WriteLine("人在洗澡");
 5         }
 6 
 7 //Boy.cs
 8 class Boy:Person
 9     {
10         public override void WashBody()
11         {
12             Console.WriteLine("男孩在洗澡");
13         }
14     }
15 
16 //Girl.cs
17 class Girl:Person
18     {
19         public override void WashBody()
20         {
21             Console.WriteLine("女孩在洗澡");
22         }
23 }
24 
25 //WashMachine.cs
26 class WashMachine
27     {
28         public void Wash(Person p)
29         {
30             Console.WriteLine("开始洗澡");
31             p.WashBody();
32             Console.WriteLine("洗澡结束");
33         }
34     }
35 
36 //Main
37 static void Main(string[] args)
38         {
39             Boy p1 = new Boy();
40             Girl p2 = new Girl();
41             WashMachine wm = new WashMachine();
42             wm.Wash(p1);//男孩洗澡        
43             wm.Wash(p2);//女孩洗澡
44             Console.ReadKey();

 1 //Pet.cs
 2 class Pet
 3 {
 4     public virtual void Shout()
 5     {
 6         Console.WriteLine("宠物叫");
 7     }
 8 }
 9 
10 //Cat.cs
11 class Cat:Pet
12 {
13     public override void Shout()
14     {
15         Console.WriteLine("猫咪叫");
16     }
17 }
18 
19 //Dog.cs
20 class Dog:Pet
21 {
22     public override void Shout()
23     {
24         Console.WriteLine("狗狗叫");
25     }
26 }
27 
28 //Shop.cs
29 class Shop
30 {
31     public Pet SellPet(string type)
32     {
33         switch(type)
34         {
35             case "dog":
36                 return new Dog();
37             case "cat"
38                 return new Cat();
39             default:
40                 return null;
41         }
42     }
43 }
44 
45 //Main
46 static void Main(string[] args)
47 {
48     Shop shop = new Shop();
49     Pet pet = shop.SellPet("dog");
50     pet.Shout();//输出"狗狗叫"
51 }