策略模式--商场促销_设计模式.rar

//商场收银软件 面向对象的编程，并不是类越多越好，类的划分是为了封装，但分类的基础是抽象，具有相同属性和功能的对象的抽象集合才是类 策略模式：它定义了算法家族，分别封装起来，让它们之间可以相互替换，此模式让算法的变化，不会影响到使用算法的客户 //抽象算法类 abstract class Strategy { public abstract void AlgorithmInterface(); } //具体算法A class ConcreteStrategyA:Strategy { public override void AlgorithmInterface() { Console.WriteLine("算法A实现"); } } //具体算法B class ConcreteStrategyB:Strategy { public override void AlgorithmInterface() { Console.WriteLine("算法B实现"); } } //具体算法C class ConcreteStrategyC:Strategy { public override void AlgorithmInterface() { Console.WriteLine("算法C实现"); } } //Context 维护一个对Strategy对象的引用 class Context { Strategy strategy; public Context(Strategy strategy) { this.strategy=strategy; } public void ContextInterface() { strategy.AlgorithmInterface(); } } //客户端代码 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(); } //简单工厂 //现金收费抽象类 abstract class CashSuper { public abstract double acceptCask(double money); } //正常收费子类 class CashNormal:CashSuper { public overrie double acceptCash(double money) { return money; } } //打折收费子类 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; } } //返利收费子类 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/monerCondition)*moneyReturn; return result; } } //现金收费工厂类 class CashFactory { 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; } } //客户端代码 double total=0.0d; private void btnOk_Click(object sender,EventArgs e) { CashSuper csuper=CashFactory.createCashAccept(cbxType.SelectItem.ToString()); double totalPrices=0d; totalPrices=csuper.acceptCash(Convert.ToDouble(txtPrice.Text)*Convert.ToDouble(txtNum.Text)) total=total=totalPrices; lbxList.Item.Add("单价:"+txtPrice.Text+"数量："+txtNum.Text+""+cbxType.SelectItem+"合计："+totalPrices.ToString()); lblResult.Text=total.ToString(); } 缺点：每次维护和扩展收费方式都要改动这个工厂 //策略模式 CashSuper,CashNormal,CashRebate,CashReturn 这些更工厂模式一样 只要加一个CashContext类 class CashContext { private CashSuper cs; pulic CashContext(CashSuper csuper) { this.cs=csuper; } public double GetResult(double money) { return cs.acceptCash(money); } } //客户端代码 double total=0.0d; private void btnOk_Click(object sender,EventArgs e) { CashContext cc=null; switch(cbxType.SelectItem.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=cs.GetResult(Convert.ToDouble(txtPrice.Text)*Convert.ToDouble(txtNum.Text)) total=total=totalPrices; lbxList.Item.Add("单价:"+txtPrice.Text+"数量："+txtNum.Text+""+cbxType.SelectItem+"合计："+totalPrices.ToString()); lblResult.Text=total.ToString(); } //策略与简单工厂结合 class CashContext { CashSuper cs=null; pulic 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); } } //客户端代码 double total=0.0d; private void btnOk_Click(object sender,EventArgs e) { CashContext csuper=new CashContext(cbxType.SelectItem.ToString()); double totalPrices=0d; totalPrices=csuper.GetResult(Convert.ToDouble(txtPrice.Text)*Convert.ToDouble(txtNum.Text)) total=total=totalPrices; lbxList.Item.Add("单价:"+txtPrice.Text+"数量："+txtNum.Text+""+cbxType.SelectItem+"合计："+totalPrices.ToString()); lblResult.Text=total.ToString(); } 策略模式： 只要在分析过程中听到需要在不同时间应用不同的业务规则，就可以考虑使用策略模式处理这种变化的可能性。