设计模式之装饰器模式

装饰器模式是一个结构型设计模式

模式类图

实例类图

   interface IHumburger
    {
        double GetPrice();
        string Name { get; }
    }

    class ChickenHumbuger : IHumburger
    {
        public double GetPrice()
        {
            return 10;
        }

        public string Name
        {
            get { return "鸡肉堡"; }
        }
    }

    class PorkHumbuger : IHumburger
    {
        public double GetPrice()
        {
            return 12;
        }

        public string Name
        {
            get { return "手撕猪肉堡"; }
        }
    }

    abstract class Condiment : IHumburger
    {
        protected IHumburger Humburger;

        protected Condiment(IHumburger humburger)
        {
            Humburger = humburger;

        }

        protected abstract double GetCondimentPrice();
        protected abstract string GetCondimentName();

        public double GetPrice()
        {
            return Humburger.GetPrice() + GetCondimentPrice();
        }

        public string Name
        {
            get { return Humburger.Name + "加" + GetCondimentName(); }
        }
    }

    class Chilli : Condiment
    {
        public Chilli(IHumburger humburger)
            : base(humburger)
        {
        }

        protected override double GetCondimentPrice()
        {
            return 1;
        }

        protected override string GetCondimentName()
        {
            return "辣椒";
        }
    }

    class Lettuce : Condiment
    {
        public Lettuce(IHumburger humburger)
            : base(humburger)
        {
        }

        protected override double GetCondimentPrice()
        {
            return 1.5;
        }

        protected override string GetCondimentName()
        {
            return "生菜";
        }
    }

    class Cheese : Condiment
    {
        public Cheese(IHumburger humburger)
            : base(humburger)
        {
        }

        protected override double GetCondimentPrice()
        {
            return 2;
        }

        protected override string GetCondimentName()
        {
            return "芝士";
        }
    }

    class Program
    {
        static void Main(string[] args)
        {

            PrintMenu();
            IHumburger humburger = new ChickenHumbuger();
            ConsoleKey key = ConsoleKey.A;
            while (key != ConsoleKey.Escape)
            {
                key = Console.ReadKey(false).Key;
                switch (key)
                {
                    case ConsoleKey.C:
                        humburger = new ChickenHumbuger();
                        break;
                    case ConsoleKey.P:
                        humburger = new PorkHumbuger();
                        break;
                    case ConsoleKey.D1:
                    case ConsoleKey.NumPad1:
                        humburger = new Lettuce(humburger);
                        break;
                    case ConsoleKey.D2:
                    case ConsoleKey.NumPad2:
                        humburger = new Chilli(humburger);
                        break;
                    case ConsoleKey.D3:
                    case ConsoleKey.NumPad3:
                        humburger = new Cheese(humburger);
                        break;
                    default:
                        Console.WriteLine("没有此选项");
                        break;
                }
                PrintDetail(humburger);
            }
            Console.ReadLine();
        }

        private static void PrintMenu()
        {
            Console.WriteLine("C.鸡肉堡");
            Console.WriteLine("P.手撕猪肉堡");
            Console.WriteLine("1.生菜");
            Console.WriteLine("2.辣椒");
            Console.WriteLine("3.");
            Console.WriteLine("Esc.点餐完成");
        }

        private static void PrintDetail(IHumburger humburger)
        {
            Console.WriteLine("汉堡名称:" + humburger.Name + "
" + "总价:" + humburger.GetPrice());
            Console.WriteLine("---------------------------------------------");
        }
    }