建造者模式(Builder Pattern)

为了应对复杂对象的创建，其通常由各个部分的子对象用一定的算法构成；由于需求的变化，这个复杂对象的各个部分经常面临着剧烈的变化，但是将它们组合在一起的算法确相对稳定。

using System;
using System.Collections;
using System.Reflection;

namespace DapperTest.Models
{
    // Food类，即产品类
    public class Food
    {
        Hashtable food = new Hashtable();
        // 添加食品
        public void Add(string strName, string Price)
        {
            food.Add(strName, Price);
        }

        // 显示食品清单
        public void Show()
        {
            IDictionaryEnumerator myEnumerator = food.GetEnumerator();
            Console.WriteLine("Food List:");
            Console.WriteLine("------------------------------");
            string strfoodlist = "";
            while (myEnumerator.MoveNext())
            {
                strfoodlist = strfoodlist + "\n\n" + myEnumerator.Key.ToString();
                strfoodlist = strfoodlist + ":\t" + myEnumerator.Value.ToString();
            }
            Console.WriteLine(strfoodlist);
            Console.WriteLine("\n------------------------------");
        }
    }
    // FoodManager类，即指导者
    public class FoodManager
    {
        public void Construct(Builder builder)
        {
            builder.BuildHamb();
            builder.BuildCoke();
            builder.BuildChip();
        }
    }
    // Builder类，即抽象建造者类，构造套餐
    public abstract class Builder
    {
        // 添加汉堡
        public abstract void BuildHamb();

        // 添加可乐
        public abstract void BuildCoke();

        // 添加薯条
        public abstract void BuildChip();

        // 返回结果 食品对象
        public abstract Food GetFood();
    }
    // NormalBuilder类，具体构造者，普通套餐
    public class NormalBuilder : Builder
    {
        private Food NormalFood = new Food();
        public override void BuildHamb()
        {
            NormalFood.Add("NormalHamb", "￥10.00");
        }
        public override void BuildCoke()
        {
            NormalFood.Add("CokeCole", "￥4.50");
        }
        public override void BuildChip()
        {
            NormalFood.Add("FireChips", "￥2.00");
        }
        public override Food GetFood()
        {
            return NormalFood;
        }
    }
    // GoldBuilder类，具体构造者，黄金套餐
    public class GoldBuilder : Builder
    {
        private Food GoldFood = new Food();
        public override void BuildHamb()
        {
            GoldFood.Add("GoldHamb", "￥25.00");
        }
        public override void BuildCoke()
        {
            GoldFood.Add("CokeCole", "￥4.50");
        }
        public override void BuildChip()
        {
            GoldFood.Add("FireChips", "￥3.50");
        }
        public override Food GetFood()
        {
            return GoldFood;
        }
    }
    //调用
    public class BuilderPattern
    {
        public static void BuildTest()
        {
            FoodManager foodmanager = new FoodManager();
            Console.WriteLine("Please Enter Food No:");
            string foodType = Console.ReadLine();
            if (foodType == "1")
            {
                foodType = "NormalBuilder";
            }
            if (foodType == "2")
            {
                foodType = "GoldBuilder";
            }
            Builder instance = (Builder)Assembly.Load("DapperTest").CreateInstance("DapperTest.Models." + foodType);
            foodmanager.Construct(instance);
            Food food = instance.GetFood();
            food.Show();
        }
    }
}