大话设计模式之策略模式代码

大话设计模式之策略模式代码：

//现金收费抽象类
    abstract class CashSuper
    {
        public abstract double acceptCash(double money);
    }
    //正常收费子类
    class CashNormal : CashSuper
    {
        public override double acceptCash(double money)
        {
            return money;
        }
    }
    //打折收费子类
    class CashRebate : CashSuper
    {
        private double moneyRebate = 1;
        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 = 0.0;
        private double moneyReturn = 0.0;
        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;
        }
    }
    public class CashContext
    {
        CashSuper cs = null;
        public CashContext(string type)
        {
            switch (type)
            {
                case "正常收费":
                    CashNormal cs0 = new CashNormal();
                    cs = cs0;
                    break;
                case "满300返100":
                    CashReturn cs1 = new CashReturn("300", "100");
                    cs = cs1;
                    break;
                case "打8折":
                    CashRebate cs2 = new CashRebate("0.8");
                    cs = cs2;
                    break;
            }
        }
        public double GetResult(double money)
        {
            return cs.acceptCash(money);
        }
    }

}

客户端代码：

namespace 商场促销__策略模式
{
    public partial class Frm1 : Form
    {
        public Frm1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            lblResult.Text = "";
        }

        private void btnOk_Click(object sender, EventArgs e)
        {
            //判断各项是否为空
            if (Convert.ToString(txtPrice.Text) == "")
            {
                MessageBox.Show("请输入单价！", "提示");
            }

            double total = 0.0;
            CashContext csuper = new CashContext(cbxType.SelectedItem.ToString());
            double totalPrices = 0;
            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 btnReSet_Click(object sender, EventArgs e)
        {
            txtPrice.Text = "";
            txtNum.Text = "";
            cbxType.Text = "";
            lbxList.Items.Clear();
            lblResult.Text = "";
            txtPrice.Focus();
        }
    }
}

界面：