设计模式之 State Pattern状态模式

State模式允许对象在内部状态变化时，变更其行为，并修改其类；

优点：

定位指定状态的行为，并且针对不同状态来划分行为，使状态转换显式进行；

适用：

对象的行为依赖于其状态，并且该对象必须在运行时根据其状态修改其行为；

操作具有大量的以及多部分组成的取决于对象状态的条件语句；

 public class Bank
    {
        private int hour;
        private Person person;
        public void SetClock(int hour)
        {
            this.hour = hour;
            Console.WriteLine($"现在时间是{hour}点");
            if (hour > 8 && hour < 18)
                ChangeState(Customer.GetInstance());
            else ChangeState(Thief.GetInstance());
        }
        public void ChangeState(Person person)
        {
            this.person = person;
            person.SayHi();

        }

    }
    public interface Person
    {
        void SayHi();

    }
    public class Customer : Person
    {
        private static Customer customer = new Customer();
        public static Customer GetInstance() => customer;
        public void SayHi()
        {
            Console.WriteLine("我是客户，我来取钱");
        }
    }
    public class Thief : Person
    {
        private static Thief thief = new Thief();
        public static Thief GetInstance() => thief;
        public void SayHi()
        {
            Console.WriteLine("我是窃贼，我来偷钱");
        }
    }
    
        public static void StatePatternTest()
        {
            Bank bank = new Bank();
            int hour = 0;
            while (true)
            {
                bank.SetClock(hour);
                hour++;
                hour %= 24;
                Thread.Sleep(1000);
            }
        
        }