会议室状态订阅（发布-订阅模式）

发布者接口

    public interface IMeetingRoom
    {
        void AddPerson(IPerson person);
        void RemovePerson(IPerson person);
        void NotifyPerson();
    }

订阅者接口

    public interface IPerson
    {
　　　　 void SubscibeMeetingRoom();
        void CancleSubscibeMeetingRoom();
        void PrintMeetingRoomMessage(string meetingRoomPublishMessage);
    }

发布者实现

　　 public class MeetingRoom : IMeetingRoom
    {
        private List<IPerson> PersonList = new List<IPerson>();
        private string meetingRoomMessage;

        public void AddPerson(IPerson person)
        {
            PersonList.Add(person);
        }

        public void NotifyPerson()
        {
            foreach(IPerson person in PersonList)
            {
                person.PrintMeetingRoomMessage(meetingRoomMessage);
            }
        }

        public void RemovePerson(IPerson person)
        {
            if(PersonList.Contains(person))
            {
                PersonList.Remove(person);
            }
        }

        public void PublishMeetingRoomStatus(bool enabled)
        {
            string strStatus = "不可用";
            if(enabled)
            {
                strStatus = "可用";
            }

            meetingRoomMessage = $"当前会议室{strStatus}";
            NotifyPerson();
        }
    }

订阅者实现

   public class PM : IPerson
    {
        private string PersonName { get; set; }
        private IMeetingRoom MeetingRoom { get; set; }

        public PM(string PMName, IMeetingRoom meetingRoom)
        {
            this.PersonName = PMName;
            this.MeetingRoom = meetingRoom;
            
        }

        public void PrintMeetingRoomMessage(string meetingRoomPublishMessage)
        {
            Console.WriteLine($"PM - {PersonName} : {meetingRoomPublishMessage}");
        }

        public void SubscibeMeetingRoom()
        {
            MeetingRoom.AddPerson(this);
        }

        public void CancleSubscibeMeetingRoom()
        {
            MeetingRoom.RemovePerson(this);
        }
    }

   public class Engineer : IPerson
    {
        private string PersonName { get; set; }
        private IMeetingRoom MeetingRoom { get; set; }

        public Engineer(string engineerName, IMeetingRoom meetingRoom)
        {
            this.PersonName = engineerName;
            this.MeetingRoom = meetingRoom;
        }

        public void PrintMeetingRoomMessage(string meetingRoomPublishMessage)
        {
            Console.WriteLine($"Engineer - {PersonName} : {meetingRoomPublishMessage}");
        }

        public void SubscibeMeetingRoom()
        {
            MeetingRoom.AddPerson(this);
        }

        public void CancleSubscibeMeetingRoom()
        {
            MeetingRoom.RemovePerson(this);
        }
    }

代码测试

        public static void Test()
        {
            MeetingRoom meetingRoom = new MeetingRoom();
            IPerson person1 = new PM("张总", meetingRoom);
            IPerson person2 = new PM("李总", meetingRoom);
            IPerson person3 = new PM("李工", meetingRoom);
            IPerson person4 = new PM("张工", meetingRoom);
            person1.SubscibeMeetingRoom();

            int num = 0;
            bool status = false;
            while (num < 6)
            {
                if (num % 2 == 0)
                {
                    status = true;
                }
                else
                {
                    status = false;
                }

                meetingRoom.PublishMeetingRoomStatus(status);

                num++;
                Console.WriteLine(num);
                if (num == 2)
                {
                    person2.SubscibeMeetingRoom();
                }

                if (num == 3)
                {
                    person3.SubscibeMeetingRoom();
                }

                if (num == 4)
                {
                    person4.SubscibeMeetingRoom();
                }
            }

            Console.ReadKey();
        }

效果