【設計模式】之備忘錄模式

• UML

• 原型

 //備忘錄
    class Memento
    {
        private string state;
        public Memento(string state)
        {
            this.State = state;
        }
        public string State { get => state; set => state = value; }
    }

 //發起人
    class Originator
    {
        //狀態（可能不止一種）
        private string state;

        public Memento CreateMemento()
        {
            return new Memento(state);
        }
        public void SetMemento(Memento m)
        {
            this.state = m.State;
        }
        public void Show()
        {
            Console.WriteLine("State=" + state);
        }
        public string State { get => state; set => state = value; }
    }

	//管理者
    class Caretaker
    {
        private Memento memento;

        public Memento Memento { get => memento; set => memento = value; }
    }

class Program
    {
        static void Main(string[] args)
        {
            Originator o = new Originator();
            o.State = "On";
            o.Show();

            Caretaker c = new Caretaker();
            c.Memento = o.CreateMemento();

            o.State = "Off";
            o.Show();

            o.SetMemento(c.Memento);
            o.Show();

        }
    }