刘铁猛老师视频课程“事件”讲解程序

刘铁猛老师视频课程“事件”讲解程序

namespace DelegateExample
{
    class Program
    {
        static void Main(string[] args)
        {
            Customer customer = new Customer();
            Waiter waiter = new Waiter();

            customer.Order += waiter.Action;
            customer.Action();
            customer.PayTheBill();
        }
    }

    public class OrderEventArgs : EventArgs
    {
        public OrderEventArgs()
        {
        }

        public string DishName { get; set; }
        public string Size { get; set; }
    }

    public delegate void OrderEventHandler(Customer cunstomer, OrderEventArgs e);

    public class Customer
    {
        private OrderEventHandler orderEventHandler;

        public event OrderEventHandler Order
        {
            add
            {
                this.orderEventHandler += value;

            }
            remove
            {
                this.orderEventHandler -= value;

            }
        }

        public double Bill { get; set; }

        public void PayTheBill()
        {
            Console.WriteLine("I will pay the Bill {0}", this.Bill);
        }

        public void WalkIn()
        {
            Console.WriteLine("Walk into the restaurant");
        }

        public void SitDown()
        {
            Console.WriteLine("Sit Down");
        }

        public void Think()
        {
            for (int i = 0; i < 5; i++)
            {
                Console.WriteLine("Let me think...");
                Thread.Sleep(1000);
            }

            if (this.orderEventHandler != null)
            {
                OrderEventArgs e = new OrderEventArgs
                {
                    DishName = "KongPao Chicken",
                    Size = "large"
                };

                this.orderEventHandler.Invoke(this, e);
            }
        }

        public void Action()
        {
            Console.ReadKey(); 
            this.WalkIn();
            this.SitDown();
            this.Think();
        }
    }

    public class Waiter
    {
        public void Action(Customer customer, OrderEventArgs e)
        {
            Console.WriteLine("I will server you the dish {0}", e.DishName);
            double price = 10.0;

            switch (e.Size)
            {
                case "small":
                    price *= 0.5;
                    break;
                case "large":
                    price *= 1.5;
                    break;
                default:
                    break;
            }

            customer.Bill += price;
        }
    }
}