设计模式之?策略模式

1     abstract class CashSupper //现金收费抽象类
2     {
3         public abstract double acceptCash(double money);//现金收取类的抽象方法，收取现金，参数为原价，返回为当前价
4     }

1     class CashNormal : CashSupper //正常收费子类
2     {
3         public override double acceptCash(double money)
4         {
5             return money;
6         }
7     }

 1     class CashRebate : CashSupper //打折收费子类
 2     {
 3         private double moneryRebate = 1d;
 4         public CashRebate(string moneryRebate)
 5         {
 6             this.moneryRebate = double.Parse(moneryRebate); //打折收费，初始化时，必须要输入折扣率，如八折，就是0.8
 7         }
 8         public override double acceptCash(double money)
 9         {
10             return money * moneryRebate;
11         }
12     }

 1  class CashReturn : CashSupper
 2     {
 3         private double moneryCondition = 0.0d;
 4         private double MoneryReturn = 0.0d;
 5         public CashReturn(string moneryCondition,string moneryReturn) //返利收费，初始化时必须要输入返利条件和返利值，比如满300返100，则moneryCondition=300，moneryReturn=100
 6         {
 7             this.moneryCondition =double.Parse(moneryCondition);
 8             this.MoneryReturn = double.Parse(moneryReturn);
 9         }
10         public override double acceptCash(double money)
11         {
12             double result = money;
13             if (money>=moneryCondition) //若大于返利条件，则需要减去返利值
14             {
15                 result = money - Math.Floor(money / moneryCondition) * MoneryReturn;
16             }
17             return result;
18         }
19     }

 1 class CashFactory
 2     {
 3         public static CashSupper createCashAccept(string type)
 4         {
 5             CashSupper cs = null;
 6             switch (type)
 7             {
 8                 case "正常收费":
 9                     cs = new CashNormal();
10                     break;
11                 case "满300反100":
12                     CashReturn cr1 = new CashReturn("300","100");
13                     cs = cr1;
14                     break;
15                 case "打8折":
16                     CashRebate cr2 = new CashRebate("0.8");
17                     cs = cr2;
18                     break;
19             }
20             return cs;
21         }
22     }

 1  class CashContext
 2     {
 3         private CashSupper cs=null; //声明一个CashSuper
 4         public CashContext(string type) //表示收费的类型
 5         {
 6             switch (type)
 7             {
 8                 case "正常收费":
 9                     CashNormal cs0 = new CashNormal();
10                     cs = cs0;
11                     break;
12                 case "满300返100":
13                     CashReturn cr1 = new CashReturn("300","100");
14                     cs = cr1;
15                     break;
16                 case "打8折":
17                     CashRebate cr2 = new CashRebate("0.8"); //将实例化具体策略的过程由客户端转移到Context类中。简单工厂的引用
18                     cs = cr2;
19                     break;
20             }
21         }
22         public double GetResult(double Money)
23         {
24             return cs.acceptCash(Money); //根据收费策略的不同，获得计算结果
25         }
26     }

 1  double total = 0.0d; //用户总计
 2         private void btnOk_Click(object sender, EventArgs e)
 3         {
 4             CashContext cc = new CashContext(cmbType.SelectedItem.ToString());
 5             double totalPrices = 0d;
 6             totalPrices = cc.GetResult(Convert.ToDouble(txtPrice.Text)*Convert.ToDouble(txtNumber.Text)); //通过对Context的GetResult方法的调用，可以得到收取费用的结果，让具体算法与客户进行隔离
 7             total = total + totalPrices;
 8             listBox1.Items.Add("单价:"+txtPrice.Text+"数量:"+txtNumber.Text+" "+cmbType.SelectedItem+"合计:"+totalPrices.ToString());
 9             label5.Text = total.ToString();
10         }