C# 設計模式實戰：Prototype 原型模式完整解析（一）

編輯：關於C語言

模式意圖

用原型實例指定建立物件的種類，並透過拷貝這些原型建立新物件。

應用場景：遊戲敵人群組生成

場景中大量相似敵人（相同技能、模型），唯位置與能力值異。若為每種能力建立子類，將爆炸性增加類別數。且步兵模型初始化極耗時。解決方案：建立單一原型 → 複製多份 → 微調屬性。

完整實作代碼


using System;
using System.Threading;
using System.Collections.Generic;
using System.IO;
using System.Runtime.Serialization.Formatters.Binary;
using System.Diagnostics;

namespace PrototypeExample
{
    class Program
    {
        static void Main(string[] args)
        {
            Stopwatch sw = new Stopwatch();
            sw.Start();

            Enemy enemyPrototype = new FootMan(5, 4, new Location(100, 200));
            GameScene gs = new GameScene();
            List<Enemy> enemyGroup = gs.CreateEnemyGroup(enemyPrototype);

            foreach (FootMan ft in enemyGroup)
            {
                ft.ShowInfo();
                ft.FootmanAttack();
            }
            Console.WriteLine(sw.ElapsedMilliseconds);
        }
    }

    class GameScene
    {
        public List<Enemy> CreateEnemyGroup(Enemy enemyPrototype)
        {
            var group = new List<Enemy>();
            Enemy e1 = enemyPrototype.Clone(true);
            e1.Location.x = enemyPrototype.Location.x - 10;

            Enemy e2 = enemyPrototype.Clone(true);
            e2.Location.x = enemyPrototype.Location.x + 10;

            Enemy elite = enemyPrototype.Clone(true);
            elite.Power = enemyPrototype.Power * 2;
            elite.Speed = enemyPrototype.Speed * 2;
            elite.Location.x = enemyPrototype.Location.x;
            elite.Location.y = enemyPrototype.Location.y + 10;

            group.Add(e1); group.Add(e2); group.Add(elite);
            return group;
        }
    }

    [Serializable]
    class Location { public int x, y; public Location(int x, int y) { this.x = x; this.y = y; } }

    [Serializable]
    abstract class Enemy
    {
        protected Location location;
        public Location Location { get { return location; } set { location = value; } }
        protected int power;
        public int Power { get { return power; } set { power = value; } }
        protected int speed;
        public int Speed { get { return speed; } set { speed = value; } }

        public abstract Enemy Clone(bool isDeepCopy);
        public abstract void ShowInfo();

        public Enemy(int power, int speed, Location location)
        {
            Thread.Sleep(1000); // 模擬高運算建構
            this.power = power; this.speed = speed; this.location = location;
        }
    }

    [Serializable]
    class FootMan : Enemy
    {
        private string model;
        public FootMan(int power, int speed, Location location) : base(power, speed, location)
        { model = "footman"; }

        public override void ShowInfo()
        {
            Console.WriteLine($"model:{model} power:{power} speed:{speed} location:({location.x},{location.y})");
        }

        public override Enemy Clone(bool isDeepCopy)
        {
            FootMan footman;
            if (isDeepCopy)
            {
                MemoryStream ms = new MemoryStream();
                BinaryFormatter formatter = new BinaryFormatter();
                formatter.Serialize(ms, this);
                ms.Position = 0;
                footman = (FootMan)formatter.Deserialize(ms);
            }
            else
                footman = (FootMan)this.MemberwiseClone();
            return footman;
        }

        public void FootmanAttack() => Console.WriteLine("FootmanAttack");
    }
}