.Net实战之反射外卖计费

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2024-08-11 04:38:42 220人阅读

场景

叫外卖支付，可以有以下优惠：

1、满30元减12

2、是会员减配送费，比如5元

3、优惠券

….

问题? 如何在不改代码的情况下更灵活的去控制优惠的变化？？？

有些代码与实际业务可能不符合，旨在体验反射的用处

   public interface IDiscount    {        /// <summary>        /// 优惠名称        /// </summary>        string Name { get; }                /// <summary>        /// 金额        /// </summary>        /// <param name="money"></param>        /// <returns></returns>        double CalcMoney(double totalMoney);    }

--代金券

namespace CashLib{    /// <summary>    /// 代金券    /// </summary>    public class CashDiscount:IDiscount    {        public string Name        {            get { return "代金券:兔子粮票2元，可抵扣2元"; }        }        public double CalcMoney(double totalMoney)        {            return totalMoney - 2;        }    }}

--会员

namespace MembeLib{    /// <summary>    /// 会员    /// </summary>    public class MemberDiscount:IDiscount    {         public string Name        {            get { return "会员免5元配送费"; }        }        public double CalcMoney(double totalMoney)        {            return totalMoney - 5;        }    }}

--满金额减免

namespace MinusLib{    /// <summary>    /// 足价减金额    /// </summary>    public class MinusDiscount : IDiscount    {        public string Name        {            get { return "满30减12元"; }        }        public double CalcMoney(double totalMoney)        {            return totalMoney - 12;        }    }}

--读取优惠策略的程序集，动态创建类的对象并调用类的成员

    public partial class Form1 : Form    {        public Form1()        {            InitializeComponent();        }        Dictionary<string, object> dict = new Dictionary<string, object>();        private void Form1_Load(object sender, EventArgs e)        {            string dllPath = AppDomain.CurrentDomain.BaseDirectory + "DiscountLib/";            string[] assFiles = System.IO.Directory.GetFiles(dllPath, "*.dll");            foreach (var dllItem in assFiles)            {                Assembly ass = Assembly.LoadFrom(dllItem);                foreach (Type type in ass.GetTypes())                {                    if (typeof(IDiscount).IsAssignableFrom(type))                    {                        object instanceDiscount = ass.CreateInstance(type.FullName);                        PropertyInfo propDiscountName = type.GetProperty("Name");                        string discountName = propDiscountName.GetValue(instanceDiscount).ToString();                        this.listBox1.Items.Add(discountName);                        dict.Add(discountName, instanceDiscount);                    }                }            }        }        private void button1_Click(object sender, EventArgs e)        {            CustomerOrder cusOrder = new CustomerOrder("张三", 35);            foreach (string item in this.listBox1.SelectedItems)            {                cusOrder.AddDiscount(dict[item] as IDiscount);            }            cusOrder.UseDiscount();        }    }