C# 設計模式實戰：Builder 建造者模式完整解析（二）

完整實作代碼：電腦組裝案例

using System;
using System.Collections.Generic;
using System.Text;
using System.Reflection;

namespace BuilderExample
{
    class Program
    {
        static void Main(string[] args)
        {
            ComputerFactory factory = new ComputerFactory();
            ComputerBuilder office = new OfficeComputerBuilder();
            factory.BuildComputer(office);
            office.Computer.ShowSystemInfo();

            ComputerBuilder game = new GameComputerBuilder();
            factory.BuildComputer(game);
            game.Computer.ShowSystemInfo();
        }
    }

    class ComputerFactory // Director
    {
        public void BuildComputer(ComputerBuilder cb)
        {
            Console.WriteLine("\n>>>>>>>>>>>>>>>>>> Start Building " + cb.Name);
            cb.SetupMainboard();
            cb.SetupCpu();
            cb.SetupMemory();
            cb.SetupHarddisk();
            cb.SetupVideocard();
            Console.WriteLine(">>>>>>>>>>>>>>>>>> Build " + cb.Name + " Completed\n");
        }
    }

    abstract class ComputerBuilder // Abstract Builder
    {
        protected string name;
        public string Name { get { return name; } set { name = value; } }
        protected Computer computer;
        public Computer Computer { get { return computer; } set { computer = value; } }

        public ComputerBuilder() { computer = new Computer(); }

        public abstract void SetupMainboard();
        public abstract void SetupCpu();
        public abstract void SetupMemory();
        public abstract void SetupHarddisk();
        public abstract void SetupVideocard();
    }

    class OfficeComputerBuilder : ComputerBuilder // Concrete Builder
    {
        public OfficeComputerBuilder() { name = "OfficeComputer"; }
        public override void SetupMainboard() => computer.Mainboard = "Abit 升技 LG-95C 主板 (Intel 945GC/LGA 775/1066MHz)";
        public override void SetupCpu() => computer.Cpu = "Intel Celeron D 336 (2.8GHz/LGA 775/256K/533MHz)";
        public override void SetupMemory() => computer.Memory = "Patriot DDR2 667 512MB";
        public override void SetupHarddisk() => computer.Harddisk = "Hitachi SATAII 80G 7200轉 8M";
        public override void SetupVideocard() => computer.Videocard = "主板集成";
    }

    class GameComputerBuilder : ComputerBuilder
    {
        public GameComputerBuilder() { name = "GameComputer"; }
        public override void SetupMainboard() => computer.Mainboard = "GIGABYTE GA-965P-DS3 3.3 主板 (Intel P965)";
        public override void SetupCpu() => computer.Cpu = "Intel Core 2 Duo E4400 (2.0GHz/LGA 775/2M/800MHz)";
        public override void SetupMemory() => computer.Memory = "G.SKILL F2-6400CL5D-2GBNQ DDR2 800 1G*2";
        public override void SetupHarddisk() => computer.Harddisk = "Hitachi SATAII 250G 7200轉 8M";
        public override void SetupVideocard() => computer.Videocard = "七彩虹 GT-GD3 UP 烈焰戰神 H10 (GeForce 8600GT/256M/DDR3/HDMI)";
    }

    class Computer // Product
    {
        private string _videocard, _cpu, _mainboard, _memory, _harddisk;
        public string Videocard { get { return _videocard; } set { _videocard = value; } }
        public string Cpu { get { return _cpu; } set { _cpu = value; } }
        public string Mainboard { get { return _mainboard; } set { _mainboard = value; } }
        public string Memory { get { return _memory; } set { _memory = value; } }
        public string Harddisk { get { return _harddisk; } set { _harddisk = value; } }

        public void ShowSystemInfo()
        {
            Console.WriteLine("==================SystemInfo==================");
            Console.WriteLine("CPU: " + _cpu);
            Console.WriteLine("MainBoard: " + _mainboard);
            Console.WriteLine("Memory: " + _memory);
            Console.WriteLine("VideoCard: " + _videocard);
            Console.WriteLine("HardDisk: " + _harddisk);
        }
    }
}

角色對應與流程

模式優勢體現

• 相同組裝流程（Director）產出截然不同配置（Builder）
• 新增機型（如 Workstation）只需新增 Builder，零修改 Director
• 建構細節封裝在 Builder，Client 僅需選擇 Builder 類型