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asp.net验证码制作实例代码

2010-05-25 09:46 861 查看
效果图


Default.aspx页面的内容

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="Verify._Default" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title>无标题页</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<img src="viewImg.aspx" />
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />
<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
</div>
</form>
</body>
</html>

Default.aspx.cs页面的内容

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;

namespace Verify
{
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}

protected void Button1_Click(object sender, EventArgs e)
{
string text = this.TextBox1.Text.ToString();//获得用户输入的验证码

string chkcode = Request.Cookies["validateCookie"].Values["ChkCode"].ToString();//获得系统生成的验证码

if (!string.IsNullOrEmpty(text) && !string.IsNullOrEmpty(chkcode))
{

if (!chkcode.Equals(chkcode.ToUpper()))//如果系统生成的不为大写则转换成大写形式

chkcode.ToUpper();

if (text.ToUpper().Trim().Equals(chkcode.Trim())) //将输入的验证码转换成大写并与系统生成的比较

this.Label1.Text = "this is right";

else
{

this.Label1.Text = "this is not right";

}

}

else if (string.IsNullOrEmpty(text))
{

this.Label1.Text = "Please input checkcode!!";

}

}
}
}

viewImg.aspx的内容

不用写任何东西

viewImg.aspx.cs

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;

namespace Verify
{
public partial class image : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

string chkCode = string.Empty;

//颜色列表,用于验证码、噪线、噪点

Color[] color ={ Color.Black, Color.Red, Color.Blue, Color.Green, Color.Orange,

Color.Brown, Color.DarkBlue };

//字体列表,用于验证码

string[] font ={ "Times New Roman", "MS Mincho", "Book Antiqua", "Gungsuh",

"PMingLiU", "Impact" };

//验证码的字符集,去掉了一些容易混淆的字符

char[] character ={ '2', '3', '4', '5', '6', '8', '9', 'A', 'B', 'C', 'D', 'E',

'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'R', 'S', 'T', 'W', 'X', 'Y' };

Random rnd = new Random();

//生成验证码字符串

for (int i = 0; i < 4; i++)
{

chkCode += character[rnd.Next(character.Length)];

}

//保存验证码的Cookie

HttpCookie anycookie = new HttpCookie("validateCookie");

anycookie.Values.Add("ChkCode", chkCode);

HttpContext.Current.Response.Cookies["validateCookie"].Values["ChkCode"] =

chkCode;

Bitmap bmp = new Bitmap(150, 30);

Graphics g = Graphics.FromImage(bmp);

g.Clear(Color.White);

//画噪线

for (int i = 0; i < 5; i++)
{

int x1 = rnd.Next(150);

int y1 = rnd.Next(30);

int x2 = rnd.Next(150);

int y2 = rnd.Next(30);

Color clr = color[rnd.Next(color.Length)];

g.DrawLine(new Pen(clr), x1, y1, x2, y2);

}

//画验证码字符串

for (int i = 0; i < chkCode.Length; i++)
{

string fnt = font[rnd.Next(font.Length)];

Font ft = new Font(fnt, 16);

Color clr = color[rnd.Next(color.Length)];

g.DrawString(chkCode[i].ToString(), ft, new SolidBrush(clr), (float)i * 20 +

20, (float)6);

}

//画噪点

for (int i = 0; i < 100; i++)
{

int x = rnd.Next(bmp.Width);

int y = rnd.Next(bmp.Height);

Color clr = color[rnd.Next(color.Length)];

bmp.SetPixel(x, y, clr);

}

//清除该页输出缓存,设置该页无缓存

Response.Buffer = true;

Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds(0);

Response.Expires = 0;

Response.CacheControl = "no-cache";

Response.AppendHeader("Pragma", "No-Cache");

//将验证码图片写入内存流,并将其以"image/Png" 格式输出

MemoryStream ms = new MemoryStream();
try
{
bmp.Save(ms, ImageFormat.Png);

Response.ClearContent();

Response.ContentType = "image/Png";

Response.BinaryWrite(ms.ToArray());

}

finally
{
//显式释放资源

bmp.Dispose();

g.Dispose();

}

}
}
}
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