C#事件

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

// 事件发布者/订阅者 EventArgs
namespace Donis.CSharpBook
{
    public class Starter
    {
        static void Main(string[] args)
        {
            Bank account = new Bank();
            account.NSF += NSFHandler;    //  订阅者
            account.Deposit(500);
            account.withdrawal(750);
        }

        public static void NSFHandler(object o, BankEventArgs e){   // 事件处理函数
            Console.WriteLine("NSF Transaction");
            Console.WriteLine("Balance: {0}", e.Balance);
            Console.WriteLine("Transaction:{0}", e.Transaction);
        }

    }

    public delegate void OverDrawn(object o, BankEventArgs e);   // 委托

    public class Bank{
        public event OverDrawn NSF;    // non-sufficient funds      委托类型的事件

        // 存入
        public decimal Deposit(decimal amountDeposit){
            propBalance += amountDeposit;
            return propBalance;
        }

        // 取钱
        public decimal withdrawal(decimal amountWithdrawn){
            decimal newBalance = propBalance - amountWithdrawn;
            if (newBalance < 0)
            {
                if (NSF != null)
                {
                    BankEventArgs args = new BankEventArgs(Balance, amountWithdrawn);  // 构造事件参数
                    NSF(this, args);           // 引发事件
                }
            }
            return propBalance = newBalance;
        }

        private decimal propBalance = 0;
        public decimal Balance
        {
            get
            {
                return propBalance;
            }
        }

    }

    public class BankEventArgs: EventArgs{   // 事件参数
                
        public BankEventArgs(decimal amountBalance, decimal amountTransaction){
            propBalance = amountBalance;
            propTransaction = amountTransaction;
        }

        // 存款余额
        private decimal propBalance;
        public decimal Balance{
            get{
                return propBalance;
            }
        }

        // 取款金额
        private decimal propTransaction;
        public decimal Transaction{
            get{
                return propTransaction;
            }
        }
    }
}

运行结果：
NSF Transaction
Balance: 500
Transaction:750