c# 备忘录模式

结构图：


memento类：保存状态的容器

    class memento
    {
        public string state { get; set; }
        public memento(string state)
        {
            this.state = state;
        }
    }

caretaker是保存memento类：

    class caretaker
    {
        public memento memento { get; set; }
    }

originator类就是需要保存状态的类：

    class originator
    {
        public string state { get; set; }
        public memento creatememento()
        {
            return (new memento(state));
        }
        public void setmemento(memento memento)
        {
            state = memento.state;
        }
        public void show()
        {
            console.writeline("state:" + state);
        }
    }

 主函数调用：

    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();
            console.readkey();
        }
    }