大话设计模式读书笔记（二）策略模式

简单工厂实现商场收费

 

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; } } }

 

 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); } }

 

 

 正常收费类（CashNormal）： 

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; } } }

 

打折收费类（CashRebate）： 

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; } } }

 

返利收费类（CasheReturn）： 

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; } } }

 

前台界面设计实现：

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"; } private void Form1_Load(object sender, EventArgs e) { } } }