using System;
using System.Collections.Generic;
using System.Text;

namespace 策略模式
{
    class Program
    {
        static void Main(string[] args)
        {
            Context context;

            context = new Context(new ConcreteStrategyA());
            context.ContextInterface();

            context = new Context(new ConcreteStrategyB());
            context.ContextInterface();

            context = new Context(new ConcreteStrategyC());
            context.ContextInterface();

            Console.Read();
        }
    }

    //抽象算法类
    abstract class Strategy
    {
        //算法方法
        public abstract void AlgorithmInterface();
    }
    //具体算法A
    class ConcreteStrategyA : Strategy
    {
        //算法A实现方法
        public override void AlgorithmInterface()
        {
            Console.WriteLine("算法A实现");
        }
    }
    //具体算法B
    class ConcreteStrategyB : Strategy
    {
        //算法B实现方法
        public override void AlgorithmInterface()
        {
            Console.WriteLine("算法B实现");
        }
    }
    //具体算法C
    class ConcreteStrategyC : Strategy
    {
        //算法C实现方法
        public override void AlgorithmInterface()
        {
            Console.WriteLine("算法C实现");
        }
    }
    //上下文
    class Context
    {
        Strategy strategy;

        public Context(Strategy strategy)  //传递任何符合要求的算法进来都可以，有利于扩展~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
        {
            this.strategy = strategy;
        }
        //上下文接口
        public void ContextInterface()
        {
            strategy.AlgorithmInterface();
        }
    }

}

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Reflection;

namespace 商场管理软件
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        double total = 0.0d;//用于总计
        private void btnOk_Click(object sender, EventArgs e)
        {
            CashContext cc = null;

            switch (cbxType.SelectedItem.ToString())      //这里客户程序做了过多的判断，所以应该另外写一个简单工厂解除客户端的压力，下一个例子就是策略模式和简单工厂的结合例子
            {
                case "正常收费":
                    cc = new CashContext(new CashNormal());
                    break;
                case "满300返100":
                    cc = new CashContext(new CashReturn("300", "100"));
                    break;
                case "打8折":
                    cc = new CashContext(new CashRebate("0.8"));
                    break;
            }

            double totalPrices = 0d;
            totalPrices = cc.GetResult(Convert.ToDouble(txtPrice.Text) * Convert.ToDouble(txtNum.Text));
            total = total + totalPrices;
            lbxList.Items.Add("单价：" + txtPrice.Text + " 数量：" + txtNum.Text + " " + cbxType.SelectedItem + " 合计：" + totalPrices.ToString());
            lblResult.Text = total.ToString();
        }

        private void btnClear_Click(object sender, EventArgs e)
        {
            total = 0d;
            txtPrice.Text = "0.00";
            txtNum.Text = "1";
            lbxList.Items.Clear();
            lblResult.Text = "0.00";
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
    }
}

    //收费策略Context
class CashContext
{
    //声明一个现金收费父类对象
    private CashSuper cs;

    //设置策略行为，参数为具体的现金收费子类（正常，打折或返利）
    public CashContext(CashSuper csuper)
    {
        this.cs = csuper;
    }

    //得到现金促销计算结果（利用了多态机制，不同的策略行为导致不同的结果）
    public double GetResult(double money)
    {
        return cs.acceptCash(money);
    }
}

  abstract class CashSuper
    {
        public abstract double acceptCash(double money);
    }


  class CashReturn : CashSuper
    {
        private double moneyCondition = 0.0d;
        private double moneyReturn = 0.0d;
        
        public CashReturn(string moneyCondition,string moneyReturn)
        {
            this.moneyCondition = double.Parse(moneyCondition);
            this.moneyReturn = double.Parse(moneyReturn);
        }

        public override double acceptCash(double money)
        {
            double result = money;
            if (money >= moneyCondition)
                result=money- Math.Floor(money / moneyCondition) * moneyReturn;
                
            return result;
        } 
    }


 class CashRebate : CashSuper
    {
        private double moneyRebate = 1d;
        public CashRebate(string moneyRebate)
        {
            this.moneyRebate = double.Parse(moneyRebate);
        }

        public override double acceptCash(double money)
        {
            return money * moneyRebate;
        } 
    }


   class CashNormal : CashSuper
    {
        public override double acceptCash(double money)
        {
            return money;
        } 
    }

namespace 商场管理软件
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        //客户端窗体程序（主要部分）
        double total = 0.0d;
        private void btnOk_Click(object sender, EventArgs e)
        {
            //利用简单工厂模式根据下拉选择框，生成相应的对象
            CashContext csuper = new CashContext(cbxType.SelectedItem.ToString());
            double totalPrices = 0d;
            //通过多态，可以得到收取费用的结果
            totalPrices = csuper.GetResult(Convert.ToDouble(txtPrice.Text) * Convert.ToDouble(txtNum.Text));
            total = total + totalPrices;
            lbxList.Items.Add("单价：" + txtPrice.Text + " 数量：" + txtNum.Text + " "
                + cbxType.SelectedItem + " 合计：" + totalPrices.ToString());
            lblResult.Text = total.ToString();
        }

        private void btnClear_Click(object sender, EventArgs e)
        {
            total = 0d;
            txtPrice.Text = "0.00";
            txtNum.Text = "0";
            lbxList.Items.Clear();
            lblResult.Text = "0.00";
        }
    }
}

    //收费策略Context和简单工厂结合
class CashContext
{
    CashSuper cs = null;

    //根据条件返回相应的对象
    public CashContext(string type)
    {
        switch (type)
        {
            case "正常收费":
                CashNormal cs0 = new CashNormal();
                cs = cs0;
                break;
            case "满300返100":
                CashReturn cr1 = new CashReturn("300", "100");
                cs = cr1;
                break;
            case "打8折":
                CashRebate cr2 = new CashRebate("0.8");
                cs = cr2;
                break;
        }
    }

    public double GetResult(double money)
    {
        return cs.acceptCash(money);
    }
}