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
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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(); } } }
策略模式-商场管理软件01简单计算
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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"; } } }
策略模式-商场管理软件02加打折
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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"; } } }
策略模式-商场管理软件03简单工厂模式
界面应用层:
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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"; } } }
现金收取工厂类 CashFactory
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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; } } }
现金收取父类 CashSuper
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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); } }
正常收费CashNormal 现金收取子类 继承CashSuper
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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; } } }
打折收费CashRebate 现金收取子类 继承CashSuper
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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; } } }
返利收费CashReturn 现金收取子类 继承CashSuper
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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; } } }
策略模式-商场管理软件04策略模式
界面应用层:
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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) { } } }
收费策略Context:
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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); } } }
父类CashSuper:
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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); } }
正常收费CashNormal 现金收取子类 继承CashSuper
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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; } } }
打折收费CashRebate 现金收取子类 继承CashSuper
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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; } } }
返利收费CashReturn 现金收取子类 继承CashSuper
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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; } } }
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:
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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"; } } }
现金收取工厂CashContext:
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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); } } }
现金收取父类CashSuper:
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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); } }
正常收费CashNormal,继承CashSuper
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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; } } }
打折收费CashRebate,继承CashSuper
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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; } } }
返利收费CashReturn,继承CashSuper
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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; } } }
策略模式源码下载:02策略模式.rar