Dunk

using System.Collections.Generic;
using System.Text;

namespace DesignModelTest.其它
{

    /// <summary>
    /// 買方付錢事件
    /// </summary>
    public class BuyerPayEventArgs : EventArgs
    {
        private string _buyerName;
        public string buyerName
        {
            get{ return _buyerName;}
            set{ _buyerName = value;}
        }
    }
    class Buyer
    {
        private string _buyerName;
        public Buyer(string name)
        {
            this._buyerName = name;
        }
        public delegate void BuyerPayEventHandler(object sender, BuyerPayEventArgs args);
        public event BuyerPayEventHandler BuyerPay;
        /// <summary>
        /// 付錢.
        /// </summary>
        public void Pay()
        {
            Console.WriteLine("我是{0}", this._buyerName);
            //觸發事件
            if (BuyerPay != null)
            {                
                BuyerPayEventArgs e = new BuyerPayEventArgs();
                e.buyerName = this._buyerName;
                //記得要丢參數及觸發
                BuyerPay(this, e);
            }
        }
    }
    class Seller
    {
        private string _sellerName;
        public Seller(string name)
        {
            this._sellerName = name;
        }
        /// <summary>
        /// 賣商品.
        /// </summary>
        /// <param name="sender">The sender.</param>
        /// <param name="args">The <see cref="DesignModelTest.其它.BuyerPayEventArgs"/> instance containing the event data.</param>
        public void Sell(object sender, BuyerPayEventArgs args)
        {
            Console.WriteLine(args.buyerName+" 付錢 , "+this._sellerName+" 賣東西");
        }
    }
}

            DesignModelTest.其它.Buyer buyer = new DesignModelTest.其它.Buyer("買方一");
            DesignModelTest.其它.Seller seller1 = new DesignModelTest.其它.Seller("賣方一");
            DesignModelTest.其它.Seller seller2 = new DesignModelTest.其它.Seller("賣方二");
            //登記事件
            buyer.BuyerPay +=new DesignModelTest.其它.Buyer.BuyerPayEventHandler(seller1.Sell);
            buyer.BuyerPay += new DesignModelTest.其它.Buyer.BuyerPayEventHandler(seller2.Sell);
            buyer.Pay();
            Console.Read();
            #endregion