Base的例子

Base的例子：using System;using System.Collections.Generic;using System.Text;namespace P80_S2305T03_04{public class Animal{public string Name;public int Age;public Animal(string initName, int initAge)//完整的构造函数{ = initName;this.Age = initAge;}public void EatFood(){ Console.WriteLine("Animal EatFood"); }}public class Cow : Animal//Animal是基类，Cow是派生类{public double weigh; //设置为public，否则，main函数无法访问public Cow(string initCowName, int initCowAge, int initWeigh): base(initCowName, initCowAge) //base调用基类的构造函数，也可用下面的方法引用 {this.weigh = initWeigh;}public void Moo(){ Console.WriteLine("Cow Moo"); }public void SupplyMilk(){ Console.WriteLine("Cow SupplyMilk"); }}public class Chicken : Animal{public Chicken(string initChickenName): base(initChickenName, 0){ }public void Cluck(){ Console.WriteLine("Chicken Cluck"); }public void LayEgg(){ Console.WriteLine("Chicken LayEgg"); }}class Program{static void Main(string[] args){//基类变量引用基类对象，调用基类共有的数据和方法Animal animal1 = new Animal("Animal1", 3);animal1.EatFood();//派生类变量引用派生类对象，调用基类共有的数据和方法，同时可调用派生类自有的数据和方法Cow cow1 = new Cow("cow1", 1, 100);cow1.EatFood();cow1.SupplyMilk();//基类变量引用派生类对象，调用基类共有的数据和方法，不能调用派生类自有的数据和方法Animal animal2 = cow1;animal2.EatFood();//animal2.SupplyMilk();//不能调用派生类自有的数据和方法Console.ReadLine();}}}例2:this的例子。

using System;using System.Collections.Generic;using System.Text;namespace P83_S2305T03_04{public class Animal{public string Name;public int Age;public Animal(): this("no name"){ }public Animal(string initName): this(initName, 0){ }public Animal(string initName, int initAge){ = initName; this.Age = initAge; }public void EatFood(){ Console.WriteLine("animal对象调用了EatFood"); }public void Breed(){ Console.WriteLine("animal对象调用了breed"); }}public class Cow : Animal{double weigh;public Cow(string initCowName, int initCowAge, int initWeigh) : base(initCowName, initCowAge){this.weigh = initWeigh;}new public void EatFood(){ Console.WriteLine("Cow对象调用了EatFood"); }public void SupplyMilk(){ Console.WriteLine("Cow对象调用了SupplyMilk");}}public class Chicken : Animal{public Chicken(string initChickenName): base(initChickenName, 0){ }new public void EatFood(){ Console.WriteLine("Chicken对象调用了EatFood"); }public void Cluck(){ Console.WriteLine("Chicken对象调用了Cluck"); }public void LayEgg(){ Console.WriteLine("Chicken对象调用了LayEgg"); }}class Program{static void Main(string[] args){ //派生类变量引用派生类对象，派生类的方法“覆盖”了基类的方法，由于加入new，因此引用派生类的方法Cow cow1=new Cow("newCow",1,100);cow1.EatFood();//基类变量引用基类对象，因为基类方法仍存在，所以仍调用基类的方法Animal animal2 = new Animal("animal1", 2);animal2.EatFood();//基类变量引用派生类对象，虽然用到new，但基类方法没有设置virtual，因此仍然调用基类的方法Animal animal3 = new Cow("newCow", 1, 100);animal3.EatFood();Console.ReadLine();}}}例3：sealed的例子using System;using System.Collections.Generic;using System.Text;namespace P83_S2305T03_04{sealed public class Animal//sealed关键字使类不能继承：sealed public class Animal {public string Name;public int Age;public Animal(): this("no name"){ }public Animal(string initName): this(initName, 0){ }public Animal(string initName, int initAge){ = initName; this.Age = initAge; }public void EatFood(){ Console.WriteLine("animal对象调用了EatFood"); }public void Breed(){ Console.WriteLine("animal对象调用了breed"); }}public class Cow : Animal{double weigh;public Cow(string initCowName, int initCowAge, int initWeigh): base(initCowName, initCowAge){this.weigh = initWeigh;}public void EatFood(){ Console.WriteLine("Cow对象调用了EatFood"); }public void SupplyMilk(){ Console.WriteLine("Cow对象调用了SupplyMilk");}}public class Chicken : Animal{public Chicken(string initChickenName): base(initChickenName, 0){ }new public void EatFood(){ Console.WriteLine("Chicken对象调用了EatFood"); }public void Cluck(){ Console.WriteLine("Chicken对象调用了Cluck"); }public void LayEgg(){ Console.WriteLine("Chicken对象调用了LayEgg"); }}class Program{static void Main(string[] args){ //派生类变量引用派生类对象，派生类的方法“覆盖”了基类的方法，由于加入new，因此引用派生类的方法Cow cow1=new Cow("newCow",1,100);cow1.EatFood();//基类变量引用基类对象，虽然用到new，但基类方法没有设置virtual，因此仍然调用基类的方法Animal animal1 = new Animal("animal1", 2);animal1.EatFood();//基类变量引用派生类对象，虽然用到new，但基类方法没有设置virtual，因此仍然调用基类的方法animal1 = cow1;animal1.EatFood();Console.ReadLine();}}}编译出现错误：错误 1 “P83_S2305T03_04.Cow”: 无法从密封类型“P83_S2305T03_04.Animal”派生F:\2011.8\C#浮莱\C#\第03章继承\课堂案例\例3：seal\P83-S2305T03_04\Program.cs27 18 P83-S2305T03_04错误 2 “P83_S2305T03_04.Chicken”: 无法从密封类型“P83_S2305T03_04.Animal”派生F:\2011.8\C#浮莱\C#\第03章继承\课堂案例\例3：seal\P83-S2305T03_04\Program.cs 42 18 P83-S2305T03_04例4：多态的例子using System;using System.Collections.Generic;using System.Text;namespace P88_S2305T04_01{public class Animal{public string Name;public int Age;public virtual void EatFood()//virtual方法定义的函数称为“虚函数”,可以被覆盖（override） { Console.WriteLine("ａｎｉｍａｌ在吃食物"); }public void Breed(){ Console.WriteLine("抚养ａｎｉｍａｌ"); }}public class Cow : Animal{//double weigh;public override void EatFood()//override重写了函数，覆盖了基类中的virtual方法{ Console.WriteLine("Cow在吃食物"); }public void SupplyMilk(){ Console.WriteLine("Cow在产奶"); }}public class Chicken : Animal{public override void EatFood()//override重写了函数，覆盖了基类中的virtual方法{ Console.WriteLine("Chicken在吃食物"); }public void Cluck(){ Console.WriteLine("Chicken对象调用了Cluck"); }public void LayEgg(){ Console.WriteLine("Chicken下蛋"); }}class Program{static void Main(string[] args){//派生类变量引用派生类对象，派生类的方法“覆盖”了基类的方法，由于加入override，因此引用派生类的方法Cow cow1 = new Cow();//cow1.EatFood();//基类变量引用基类对象，因为基类方法仍存在，所以仍调用基类的方法Animal animal1 = new Animal();//animal1.EatFood();//基类变量引用派生类对象，因为基类的方法已被override（覆盖或重写)，因此调用派生类的方法Animal animal2 =new Cow();animal2.EatFood();Console.ReadLine();}}}。