Code
 1 using System;
 2 using System.Collections.Generic;
 3 using System.Text;
 4 
 5 namespace CreditCardForm
 6 {
 7     public class ValidateCreditCardFormEventArgs:EventArgs 
 8     {
 9         private string paymentMethod;
10         public string PaymentMethod
11         {
12             get
13             {
14                 return this.paymentMethod;
15             }
16         }
17 
18 
19         private string creditCardNo;
20         public string CreditCardNo
21         {
22             get
23             {
24                 return this.creditCardNo;
25             }
26         }
27 
28 
29         private string cardholderName;
30         public string CardholderName
31         {
32             get
33             {
34                 return this.cardholderName;
35             }
36         }
37 
38         private DateTime expirationDate;
39         public DateTime ExpirationDate
40         {
41             get
42             {
43                 return this.expirationDate;
44             }
45         }
46 
47 
48         public ValidateCreditCardFormEventArgs(string paymentmenthod, string creditcardno,
49             string cardholdername, DateTime expirationdate)
50         {
51             this.paymentMethod = paymentmenthod;
52             this.creditCardNo = creditcardno;
53             this.cardholderName = cardholdername;
54             this.expirationDate = expirationdate;
55         }
56     }
57 }
58 

Code
1 using System;
2 using System.Collections.Generic;
3 using System.Text;
4 
5 namespace CreditCardForm
6 {
7     public delegate void ValidateCreditCardFormEventHandler(object sender,ValidateCreditCardFormEventArgs args);
8 }
9 

Code
1  public event ValidateCreditCardFormEventHandler ValidateCreditCardForm;

Code
1  
2 //这个方法是受保护的虚方法
3 protected void OnValidateCreditCardForm(ValidateCreditCardFormEventArgs args)
4         {
5              if (ValidateCreditCardForm != null)
6                 handler(this, args);
7         }