第2章 策略模式

封装变化点是面向对象的一种重要思维方式。

策略模式是一种定义一系列算法的方法，从概念上来看，所有这些算法完成的都是相同的工作，只是实现不同，它可以额以相同的方式调用所有的算法，减少了各种算法类与使用算法类直接的耦合。

 

 策略模式-基本代码

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)
        {
            this.strategy = strategy;
        }
        //上下文接口
        public void ContextInterface()
        {
            strategy.AlgorithmInterface();
        }
    }

}
View Code

 

策略模式-商场管理软件01简单计算

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

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

        //声明一个double变量total来计算总计
        double total = 0.0d;
        private void btnOk_Click(object sender, EventArgs e)
        {
            //声明一个double变量totalPrices来计算每个商品的单价（txtPrice）*数量(txtNum)后的合计
            double totalPrices=Convert.ToDouble(txtPrice.Text) * Convert.ToDouble(txtNum.Text);
            //将每个商品合计计入总计
            total = total + totalPrices;
            //在列表框中显示信息
            lbxList.Items.Add("单价："+txtPrice.Text+" 数量："+txtNum.Text+" 合计："+totalPrices.ToString());
            //在lblResult标签上显示总计数
            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";
        }
    }
}
View Code

 

策略模式-商场管理软件02加打折

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

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

        double total = 0.0d;
  
        private void Form1_Load(object sender, EventArgs e)
        {
            cbxType.Items.AddRange(new object[] {"正常收费","打八折","打七折","打五折"});
            cbxType.SelectedIndex = 0;
        }

        private void btnOk_Click(object sender, EventArgs e)
        {
            double totalPrices=0d;
            switch(cbxType.SelectedIndex)
            {
                case 0:
                    totalPrices = Convert.ToDouble(txtPrice.Text) * Convert.ToDouble(txtNum.Text);
                    break;
                case 1:
                    totalPrices = Convert.ToDouble(txtPrice.Text) * Convert.ToDouble(txtNum.Text) * 0.8;
                    break;
                case 2:
                    totalPrices = Convert.ToDouble(txtPrice.Text) * Convert.ToDouble(txtNum.Text) * 0.7;
                    break;
                case 3:
                    totalPrices = Convert.ToDouble(txtPrice.Text) * Convert.ToDouble(txtNum.Text) * 0.5;
                    break;

            }
            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";
        }

        
    }
}
View Code

 

策略模式-商场管理软件03简单工厂模式

界面应用层：

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

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
            CashSuper csuper = CashFactory.createCashAccept(cbxType.SelectedItem.ToString());
            double totalPrices = 0d;
            //通过多态，可以得到收取费用的结果
            totalPrices = csuper.acceptCash(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";
        }
    }
}
View Code

现金收取工厂类 CashFactory

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

namespace 商场管理软件
{
//现金收取工厂
class CashFactory
{
    //根据条件返回相应的对象
    public static CashSuper createCashAccept(string type)
    {
        CashSuper cs = null;
        switch (type)
        {
            case "正常收费":
                cs = new CashNormal();
                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;
        }
        return cs;
    }
}
}
View Code

现金收取父类 CashSuper

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

namespace 商场管理软件
{
//现金收取父类
abstract class CashSuper
{
    //抽象方法：收取现金，参数为原价，返回为当前价
    public abstract double acceptCash(double money);
}

}
View Code

正常收费CashNormal  现金收取子类 继承CashSuper

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

namespace 商场管理软件
{
    //正常收费，继承CashSuper
    class CashNormal : CashSuper
    {
        public override double acceptCash(double money)
        {
            return money;
        }
    }

}
View Code

打折收费CashRebate  现金收取子类 继承CashSuper

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

namespace 商场管理软件
{
    //打折收费，继承CashSuper
    class CashRebate : CashSuper
    {
        private double moneyRebate = 1d;
        //初始化时，必需要输入折扣率,如八折，就是0.8
        public CashRebate(string moneyRebate)
        {
            this.moneyRebate = double.Parse(moneyRebate);
        }

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

返利收费CashReturn  现金收取子类 继承CashSuper

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

namespace 商场管理软件
{
    //返利收费，继承CashSuper
    class CashReturn : CashSuper
    {
        private double moneyCondition = 0.0d;
        private double moneyReturn = 0.0d;
        //初始化时必须要输入返利条件和返利值，比如满300返100，则moneyCondition为300，moneyReturn为100
        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;
            //若大于返利条件，则需要减去返利值
            if (money >= moneyCondition)
                result = money - Math.Floor(money / moneyCondition) * moneyReturn;

            return result;
        }
    }
}
View Code

 

策略模式-商场管理软件04策略模式

界面应用层：

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())
            {
                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)
        {

        }
    }
}
View Code

收费策略Context：

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

namespace 商场管理软件
{
    //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);
    }
}
}
View Code

父类CashSuper：

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

namespace 商场管理软件
{
    abstract class CashSuper
    {
        public abstract double acceptCash(double money);
    }
}
View Code

正常收费CashNormal  现金收取子类 继承CashSuper

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

namespace 商场管理软件
{
    class CashNormal : CashSuper
    {
        public override double acceptCash(double money)
        {
            return money;
        } 
    }
}
View Code

打折收费CashRebate  现金收取子类 继承CashSuper

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

namespace 商场管理软件
{
    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;
        } 
    }
}
View Code

返利收费CashReturn  现金收取子类 继承CashSuper

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

namespace 商场管理软件
{
    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;
        } 
    }
}
View Code

 

策略模式-商场管理软件05简单工厂和策略模式

 界面应用层：

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

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";
        }
    }
}
View Code

现金收取工厂CashContext：

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

namespace 商场管理软件
{
    //现金收取工厂
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);
    }
}
}
View Code

现金收取父类CashSuper：

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

namespace 商场管理软件
{
//现金收取父类
abstract class CashSuper
{
    //抽象方法：收取现金，参数为原价，返回为当前价
    public abstract double acceptCash(double money);
}

}
View Code

正常收费CashNormal，继承CashSuper

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

namespace 商场管理软件
{
    //正常收费，继承CashSuper
    class CashNormal : CashSuper
    {
        public override double acceptCash(double money)
        {
            return money;
        }
    }

}
View Code

打折收费CashRebate，继承CashSuper

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

namespace 商场管理软件
{
    //打折收费，继承CashSuper
    class CashRebate : CashSuper
    {
        private double moneyRebate = 1d;
        //初始化时，必需要输入折扣率,如八折，就是0.8
        public CashRebate(string moneyRebate)
        {
            this.moneyRebate = double.Parse(moneyRebate);
        }

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

返利收费CashReturn，继承CashSuper

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

namespace 商场管理软件
{
    //返利收费，继承CashSuper
    class CashReturn : CashSuper
    {
        private double moneyCondition = 0.0d;
        private double moneyReturn = 0.0d;
        //初始化时必须要输入返利条件和返利值，比如满300返100，则moneyCondition为300，moneyReturn为100
        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;
            //若大于返利条件，则需要减去返利值
            if (money >= moneyCondition)
                result = money - Math.Floor(money / moneyCondition) * moneyReturn;

            return result;
        }
    }
}
View Code

 

 

 策略模式源码下载：02策略模式.rar

 

posted @ 2014-06-20 13:52  IT浪潮之巅  阅读(155)  评论(0)    收藏  举报
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