namespace 商城收銀管理
{//收費政策Context
class CashContext
{
private CashSuper cs; //聲明一個現金收費父類對象cs
//設定政策行為,參數具體的現金收費子類(正常,打折或返利)
public CashContext(CashSuper csuper)//通過政策方法,傳入具體的收費政策
{
this.cs = csuper;
}
public double GetResult(double money)
{
return cs.acceptCash(money);//根據收費政策的不同,獲得計算結果
}
}
}
用戶端代碼
namespace 商城收銀管理
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
double total = 0.0d;
private void btnOk_Click(object sender, EventArgs e)
{
CashContext cc= null;
switch (cbxType.SelectedItem.ToString())//根據希臘選擇框,講相應的政策對象作為參數傳入CashContect對象中
{
case"正常收費":
cc = new CashContext(new cashNormal());
break;
case "滿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));//通過對Context的GetResult方法的調用,可以得到收取費用的結果,讓具體算法與客戶進行了隔離
total = total + totalPrices;
lbxList.Items.Add("單價:" + txtPrice.Text + " 數量:" + txtNum.Text + " " + cbxType.SelectedItem + " 合計:" + totalPrices.ToString());
lblResult.Text = total.ToString();
}
private void btnClear_Click(object sender, EventArgs e)
{
total = 0;
txtPrice.Text = "1";
txtNum.Text = "0.00";
lbxList.Items.Clear();
lblResult.Text = "0.00";
}
}
}
其他算法類
namespace 商城收銀管理
{
class cashNormal:CashSuper
{
public override double acceptCash(double money)
{
return money;
}
}
}
namespace 商城收銀管理
{
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;
}
}
}