(转)验证码
1CheckCode.aspx.cs
2/*********************************************************************/
3using System;
4using System.Data;
5using System.Configuration;
6using System.Collections;
7using System.Web;
8using System.Web.Security;
9using System.Web.UI;
10using System.Web.UI.WebControls;
11using System.Web.UI.WebControls.WebParts;
12using System.Web.UI.HtmlControls;
13using System.Drawing;
14public partial class CheckCode : System.Web.UI.Page
15{
16 private void Page_Load(object sender, System.EventArgs e)
17 {
18 this.CreateCheckCodeImage(GenerateCheckCode());
19 }
20 private string GenerateCheckCode()
21 {
22 int number;
23 char code;
24 string checkCode = String.Empty;
25 System.Random random = new Random();
26 for (int i = 0; i < 5; i++)
27 {
28 number = random.Next();
29 if (number % 2 == 0)
30 code = (char)('0' + (char)(number % 10));
31 else
32 code = (char)('A' + (char)(number % 26));
33 checkCode += code.ToString();
34 }
35 Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));
36 return checkCode;
37 }
38 private void CreateCheckCodeImage(string checkCode)
39 {
40 if (checkCode == null || checkCode.Trim() == String.Empty)
41 return;
42 System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22);
43 Graphics g = Graphics.FromImage(image);
44 try
45 {
46 //生成随机生成器
47 Random random = new Random();
48 //清空图片背景色
49 g.Clear(Color.White);
50 //画图片的背景噪音线
51 for (int i = 0; i < 25; i++)
52 {
53 int x1 = random.Next(image.Width);
54 int x2 = random.Next(image.Width);
55 int y1 = random.Next(image.Height);
56 int y2 = random.Next(image.Height);
57
58 g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
59 }
60 Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
61 System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
62 g.DrawString(checkCode, font, brush, 2, 2);
63 //画图片的前景噪音点
64 for (int i = 0; i < 100; i++)
65 {
66 int x = random.Next(image.Width);
67 int y = random.Next(image.Height);
68
69 image.SetPixel(x, y, Color.FromArgb(random.Next()));
70 }
71 //画图片的边框线
72 g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
73 System.IO.MemoryStream ms = new System.IO.MemoryStream();
74 image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
75 Response.ClearContent();
76 Response.ContentType = "image/Gif";
77 Response.BinaryWrite(ms.ToArray());
78 }
79 finally
80 {
81 g.Dispose();
82 image.Dispose();
83 }
84 }
85}
登录页面中使用“<ImageButton>” 这个 HTML 元素来显示生成的验证码图片:<asp:ImageButton ID="ImageButton1" ImageUrl="CheckCode.aspx" runat="server"/>
在登录页面的登录按钮的处理事件中使用以下代码判断验证码:
private void btnLogin_Click(object sender, System.Web.UI.ImageClickEventArgs e)
{
if(Request.Cookies["CheckCode"] == null)
{
lblMessage.Text = "您的浏览器设置已被禁用 Cookies,您必须设置浏览器允许使用 Cookies 选项后才能使用本系统。";
lblMessage.Visible = true;
return;
}
2/*********************************************************************/
3using System;
4using System.Data;
5using System.Configuration;
6using System.Collections;
7using System.Web;
8using System.Web.Security;
9using System.Web.UI;
10using System.Web.UI.WebControls;
11using System.Web.UI.WebControls.WebParts;
12using System.Web.UI.HtmlControls;
13using System.Drawing;
14public partial class CheckCode : System.Web.UI.Page
15{
16 private void Page_Load(object sender, System.EventArgs e)
17 {
18 this.CreateCheckCodeImage(GenerateCheckCode());
19 }
20 private string GenerateCheckCode()
21 {
22 int number;
23 char code;
24 string checkCode = String.Empty;
25 System.Random random = new Random();
26 for (int i = 0; i < 5; i++)
27 {
28 number = random.Next();
29 if (number % 2 == 0)
30 code = (char)('0' + (char)(number % 10));
31 else
32 code = (char)('A' + (char)(number % 26));
33 checkCode += code.ToString();
34 }
35 Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));
36 return checkCode;
37 }
38 private void CreateCheckCodeImage(string checkCode)
39 {
40 if (checkCode == null || checkCode.Trim() == String.Empty)
41 return;
42 System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22);
43 Graphics g = Graphics.FromImage(image);
44 try
45 {
46 //生成随机生成器
47 Random random = new Random();
48 //清空图片背景色
49 g.Clear(Color.White);
50 //画图片的背景噪音线
51 for (int i = 0; i < 25; i++)
52 {
53 int x1 = random.Next(image.Width);
54 int x2 = random.Next(image.Width);
55 int y1 = random.Next(image.Height);
56 int y2 = random.Next(image.Height);
57
58 g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
59 }
60 Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
61 System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
62 g.DrawString(checkCode, font, brush, 2, 2);
63 //画图片的前景噪音点
64 for (int i = 0; i < 100; i++)
65 {
66 int x = random.Next(image.Width);
67 int y = random.Next(image.Height);
68
69 image.SetPixel(x, y, Color.FromArgb(random.Next()));
70 }
71 //画图片的边框线
72 g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
73 System.IO.MemoryStream ms = new System.IO.MemoryStream();
74 image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
75 Response.ClearContent();
76 Response.ContentType = "image/Gif";
77 Response.BinaryWrite(ms.ToArray());
78 }
79 finally
80 {
81 g.Dispose();
82 image.Dispose();
83 }
84 }
85}
登录页面中使用“<ImageButton>” 这个 HTML 元素来显示生成的验证码图片:<asp:ImageButton ID="ImageButton1" ImageUrl="CheckCode.aspx" runat="server"/>
在登录页面的登录按钮的处理事件中使用以下代码判断验证码:
private void btnLogin_Click(object sender, System.Web.UI.ImageClickEventArgs e)
{
if(Request.Cookies["CheckCode"] == null)
{
lblMessage.Text = "您的浏览器设置已被禁用 Cookies,您必须设置浏览器允许使用 Cookies 选项后才能使用本系统。";
lblMessage.Visible = true;
return;
}
if(String.Compare(Request.Cookies["CheckCode"].Value, txtCheckCode.Text, true) != 0)
{
lblMessage.Text = "验证码错误,请输入正确的验证码。";
lblMessage.Visible = true;
return;
}
}
http://www.spdevelop.com/forum/Answer.aspx?QuestionId=38