《C#入门详解》刘老师 接口，依赖反转，单元测试

接口，依赖反转，单元测试

一、IEnumerable接口使用

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

namespace IEnumerable接口使用
{
    class Program
    {
        static void Main(string[] args)
        {
            int[] nums1 = new int[] { 1, 2, 3, 4, 5 };
            ArrayList nums2 = new ArrayList { 1, 2, 3, 4, 5 };
            Console.WriteLine(sum(nums2));
            Console.WriteLine(Avg(nums2));
            Console.WriteLine(sum(nums1));
            Console.WriteLine(Avg(nums1));
        }
        //供方为整形数组和Arraylist    供方Array实现了IEnumerable接口，Arraylist也实现了IEnumerable这个接口，Array和Arraylist都遵守这个锲约保证自己可以被迭代
        //需方为Sum  和  Avg这两个函数   ，需方我只要求你传进来的参数可以被迭代就行了，因为我要用foreach循环去迭代里面的每一个整数

        //供方需方都遵守IEnumerable接口这个锲约
        static int sum(IEnumerable nums)  //int[] nums     ;;  ArrayList nums(object类型的所以要加int)
        {
            int sum = 0;
            foreach (var n in nums) sum += (int )n;
            return sum;
        }

        static double Avg(IEnumerable nums)
        {
            int sum = 0;
            double count = 0;
            foreach( var n in nums) { sum +=(int) n;count++; }
            return sum / count;
        }

    }
}

 二、接口（供需双方都满足的锲约）

类与类之间，对象与对象之间分工合作，面向对象世界里有一个术语叫做依赖，服务的提供者和服务的使用者之间有一个依赖关系。实现接口，必须要把接口里的所有成员全部实现。

/*========人和手机之间是解耦的============*/

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

namespace Interface_Example
{
    class Program
    {
        static void Main(string[] args)
        {
            // IPhone V = new NokiaPhone();实现接口的实例
            var user = new PhoneUSER(new NokiaPhone());      //(V);
            user.usephone();
        }
    }


    class PhoneUSER
    {
        private IPhone _phone;
        public PhoneUSER (IPhone phone)
        {
            _phone = phone;
        }
        public void usephone()
        {
            _phone.Dial();
            _phone.PickUP();
            _phone.Send();
            _phone.Receive();

        }


    }



    interface IPhone
    {
        void Dial();
        void PickUP();
        void Send();
        void Receive();

    }

    class NokiaPhone : IPhone
    {
        public void Dial()
        {
            Console.WriteLine("Nokia calling...");
        }

        public void PickUP()
        {
            Console.WriteLine("Hello,this is tim");
        }

        public void Receive()
        {
            Console.WriteLine("Nokia message ring...");
        }

        public void Send()
        {
            Console.WriteLine("hello");
        }
    }

    class EricssonPhone : IPhone
    {
        public void Dial()
        {
            Console.WriteLine("EricssonPhone calling...");
        }

        public void PickUP()
        {
            Console.WriteLine("hi,this is tim");
        }

        public void Receive()
        {
            Console.WriteLine("Ericsson message ring...");
        }

        public void Send()
        {
            Console.WriteLine("good evening");
        }
    }


}

人和手机之间是解耦的。

三、依赖反转

人和手机之间是解耦的。什么是解耦？解耦在代码中的表现就是依赖反转（依赖倒置）。单元测试就是依赖反转在开发中的直接应用。

/*============强耦合，依赖关系，电扇依赖电源=======*/
using System;

namespace InterfaceExample
{

    class Program
      {
       var fan = new DeskFan(new PowerSupply());
       Console.Writeline(fan.Work());
       }
    class PowerSupply
      {
        public int GetPower()
          {
            return 100;
           }
       }

    class DeskFan
      {
        private PowerSupply _powerSupply;
        public DeskFan(PowerSupply powerSupply)
          {
             _powerSupply = powerSupply;
           }
         public string Work()
           {
            int power = _powerSupply.GetPower();
            if (power<=0)
            {return "won't work!!!!";}
            else if(power<100)
            {return "slow!!!!";}
             else if(power<200)
             {return "work fine!!!!!!";}
             else
             {return "warning!!!!!!";}
             } 
       }

}

/*===================解耦==================*/
using System;

namespace InterfaceExample
{

    class Program
      {
       var fan = new DeskFan(new PowerSupply());
       Console.Writeline(fan.Work());

       }

    InterFace IPowerSupply
      { int GetPower();}


    class PowerSupply : IPowerSupply
      {
        public int GetPower()
          {
            return 100;
           }
       }

    class DeskFan
      {
        private IPowerSupply _powerSupply;
        public DeskFan(IPowerSupply powerSupply)
          {
             _powerSupply = powerSupply;
           }
         public string Work()
           {
            int power = _powerSupply.GetPower();
            if (power<=0)
            {return "won't work!!!!";}
            else if(power<100)
            {return "slow!!!!";}
             else if(power<200)
             {return "work fine!!!!!!";}
             else
             {return "warning!!!!!!";}

             } 


       }



}

四、单元测试