C#多态的三种实现方式(小结)

class Person
{
  public Person(string name)
  {
    this.Name = name;
  }

  string _name;

  public string Name { get => _name; set => _name = value; }

  //父类方法加virtual，子类用override重写该方法，就实现了多态 
  public virtual void SayHello()  
  {
    Console.WriteLine("我是父类的方法");
  }
}

class Student : Person
{
  public Student(string name) : base(name) { }

  public override void SayHello()
  {
    Console.WriteLine("我叫{0}, 我是学生", this.Name);
  }
}

class Teacher:Person
{
  public Teacher(string name) : base(name) { }

  public override void SayHello()
  {
    Console.WriteLine("我叫{0}, 我是老师", this.Name);
  }
}

Student st = new Student("李雷");
Teacher th = new Teacher("井边君");

Person[] p = { st, th }; //子类对象赋给父类

for(int i = 0; i < p.Length; i++)
{
  p[i].SayHello();
}

Console.ReadKey();

using System;

namespace 多态之虚方法
{
  class Program
  {
    static void Main(string[] args)
    {
      Student st = new Student("李雷");
      Teacher th = new Teacher("井边君");

      Person[] p = { st, th }; //子类对象赋给父类

      for(int i = 0; i < p.Length; i++)
      {
        p[i].SayHello();
      }

      Console.ReadKey();
    }
  }

  class Person
  {
    public Person(string name)
    {
      this.Name = name;
    }

    string _name;

    public string Name { get => _name; set => _name = value; }

    //父类方法加virtual，子类用override重写该方法，就实现了多态 
    public virtual void SayHello()  
    {
      Console.WriteLine("我是父类的方法");
    }
  }

  class Student : Person
  {
    public Student(string name) : base(name) { }

    public override void SayHello()
    {
      Console.WriteLine("我叫{0}, 我是学生", this.Name);
    }
  }

  class Teacher:Person
  {
    public Teacher(string name) : base(name) { }

    public override void SayHello()
    {
      Console.WriteLine("我叫{0}, 我是老师", this.Name);
    }
  }
}

using System;
using System.Collections.Generic;

namespace 多态之抽象类
{
  abstract class Person
  {
    //抽象方法不能有函数体
    public abstract void SayHello();
  }

  class Student : Person
  {
    public override void SayHello()
    {
      Console.WriteLine("我是子类Student重写的抽象方法"); ;
    }
  }

  class Teacher : Person
  {
    public override void SayHello()
    {
      Console.WriteLine("我是子类Teacher重写的抽象方法"); ;
    }
  }

  class Program
  {
    static void Main(string[] args)
    {
      List<Person> clist = new List<Person>();

      Student st = new Student();
      Teacher th = new Teacher();
      clist.Add(st);
      clist.Add(th);

      foreach(Person p in clist)
      {
        p.SayHello();
      }

      Console.ReadKey();
    }
  }
}

using System;
using System.Collections.Generic;

namespace 多态之接口
{
  public interface IWeapon
  {
    void Fire();
  }

  class Gun : IWeapon
  {
    public void Fire()
    {
      Console.WriteLine("我是枪");
    }
  }

  class Sword : IWeapon
  {
    public void Fire()
    {
      Console.WriteLine("我是剑");
    }

  }

  class Tank : IWeapon
  {
    public void Fire()
    {
      Console.WriteLine("我是坦克");
    }
  }

  class Program
  {
    static void Main(string[] args)
    {
      List<IWeapon> list = new List<IWeapon>();

      Gun gun = new Gun();
      Sword sw = new Sword();
      Tank ta = new Tank();
      list.Add(gun);
      list.Add(sw);
      list.Add(ta);

      foreach (IWeapon p in list)
      {
        p.Fire();
      }

      Console.ReadKey();
    }
  }
}