C#视频 - 虚方法， virtual，abstract方法

Note： virtual 和 abstract 方法不能声明为 private。

  1 using System;
  2 using System.Collections.Generic;
  3 using System.Linq;
  4 using System.Text;
  5 using System.Threading.Tasks;
  6 using System.Collections;
  7 
  8 namespace ConsoleApplication1
  9 {
 10 
 11     class Employee
 12     {
 13         private string _name;
 14 
 15         public Employee(string name)
 16         {
 17             this._name = name;
 18         }
 19 
 20         public string Name
 21         {
 22             get
 23             {
 24                 return this._name;
 25             }
 26         }
 27 
 28         public virtual void startWork()
 29         {
 30             Console.WriteLine("{0} starts work.", this._name);
 31         }
 32     }
 33 
 34     class Manager : Employee
 35     {
 36         public Manager(string name): base(name)
 37         {
 38             
 39         }
 40 
 41         public override void startWork()
 42         {
 43             Console.WriteLine("{0} starts to distrubit tasks", base.Name);
 44         }
 45     }
 46 
 47     class Secretary : Employee
 48     {
 49         public Secretary(string name)
 50             : base(name)
 51         {
 52 
 53         }
 54 
 55         public override void startWork()
 56         {
 57             Console.WriteLine("{0} starts to help", base.Name);
 58         }
 59     }
 60 
 61     class Seller : Employee
 62     {
 63         public Seller(string name)
 64             : base(name)
 65         {
 66 
 67         }
 68 
 69         public override void startWork()
 70         {
 71             Console.WriteLine("{0} starts to sell", base.Name);
 72         }
 73     }
 74 
 75     class Accountant : Employee
 76     {
 77         public Accountant(string name)
 78             : base(name)
 79         {
 80 
 81         }
 82 
 83         public override void startWork()
 84         {
 85             Console.WriteLine("{0} starts to compute", base.Name);
 86         }
 87     }
 88 
 89     class Program
 90     {
 91         static void Main(string[] args)
 92         {
 93             Employee[] es = new Employee[5];
 94 
 95             es[0] = new Employee("Tim");
 96             es[1] = new Manager("Gan");
 97             es[2] = new Secretary("Kate");
 98             es[3] = new Seller("Jim");
 99             es[4] = new Accountant("Tata");
100 
101             foreach(Employee e in es)
102             {
103                 e.startWork();
104             }
105 
106             Console.ReadKey();
107         }
108     }
109 }

View Code

抽象方法：

抽象方法本身就是一个隐含的virtual虚方法，也可以实现多态。抽象方法必须声明在抽象类中。抽象方法不能声明为private。

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

namespace ConsoleApplication1
{

    abstract class Employee
    {
        private string _name;

        protected Employee(string name)
        {
            this._name = name;
        }

        public string Name
        {
            get
            {
                return this._name;
            }
        }

        public abstract void startWork();
    }

    class Manager : Employee
    {
        public Manager(string name)
            : base(name)
        {

        }

        public override void startWork()
        {
            Console.WriteLine("{0} starts to distrubit tasks", base.Name);
        }
    }

    class Secretary : Employee
    {
        public Secretary(string name)
            : base(name)
        {

        }

        public override void startWork()
        {
            Console.WriteLine("{0} starts to help", base.Name);
        }
    }

    class Seller : Employee
    {
        public Seller(string name)
            : base(name)
        {

        }

        public override void startWork()
        {
            Console.WriteLine("{0} starts to sell", base.Name);
        }
    }

    class Accountant : Employee
    {
        public Accountant(string name)
            : base(name)
        {

        }

        public override void startWork()
        {
            Console.WriteLine("{0} starts to compute", base.Name);
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            Employee[] es = new Employee[5];

            es[0] = new Manager("YY");
            es[1] = new Manager("Gan");
            es[2] = new Secretary("Kate");
            es[3] = new Seller("Jim");
            es[4] = new Accountant("Tata");

            foreach (Employee e in es)
            {
                e.startWork();
            }

            Console.ReadKey();
        }
    }
}

View Code

虚方法和抽象方法：
当所有子类都要实现一些共同的功能的时候，应用虚方法。

包含抽象方法的类不能被实例化，而包含virtual的类则可以。

posted on 2018-05-31 10:59 zzunstu 阅读(117) 评论(0) 编辑收藏举报