static void Main(string[] args)
{
//何时使用：很多时候我们总是需要记录一个对象的内部状态，这样做的目的就是为了允许用户取消不确定或者错误的操作，能够恢复到他原先的状态，使得他有"后悔药"可吃。
Originator originator = new Originator();
CareTaker careTaker = new CareTaker();
originator.SetState("State #1");
originator.SetState("State #2");
careTaker.Add(originator.SaveStateToMemento());
originator.SetState("State #3");
careTaker.Add(originator.SaveStateToMemento());
originator.SetState("State #4");
Console.WriteLine("Current State: " + originator.GetState());
originator.GetStateFromMemento(careTaker.Get(0));
Console.WriteLine("First saved State: " + originator.GetState());
originator.GetStateFromMemento(careTaker.Get(1));
Console.WriteLine("Second saved State: " + originator.GetState());
Console.ReadLine();
}
public Caretaker(Originator <T> originator)
{
this._originator = originator;
}