asp.net中验证码的实现 (转自http://blog.csdn.net/zhoufoxcn/archive/2007/07/19/1698615.aspx)
主要用到一个类，一个aspx页面，还有一个使用图片验证码的aspx页面。
随机图片生成类：
using System;
using System.Collections.Generic;
using System.Text;
using System.Drawing;
namespace Sooyie.Common
{
/// <summary>
/// 产生随即图片
/// </summary>
public sealed class RandImage
{
private const string RandCharString = "0123456789";
private int width;
private int height;
private int length;
/// <summary>
/// 默认构造函数，生成的图片宽度为48×24，随即字符串字符个数
/// </summary>
public RandImage():this(48,24,4)
{
}
/// <summary>
/// 指定生成图片的宽和高，默认生成图片的字符串长度为4个字符
/// </summary>
/// <param name="width"></param>
/// <param name="height"></param>
public RandImage(int width, int height):this(width,height,4)
{
}
/// <summary>
/// 指定生成图片的宽和高以及生成图片的字符串字符个数
/// </summary>
/// <param name="width"></param>
/// <param name="height"></param>
/// <param name="length"></param>
public RandImage(int width, int height, int length)
{
this.width = width;
this.height = height;
this.length = length;
}
/// <summary>
/// 以默认的大小和默认的字符个数产生图片
/// </summary>
/// <returns></returns>
public Image GetImage()
{
Bitmap image = new Bitmap(width, height);
Graphics g = Graphics.FromImage(image);
g.Clear(Color.White);
string randString = "";
Random random=new Random();
do
{
randString += RandCharString.Substring(random.Next((int)DateTime.Now.Ticks)%RandCharString.Length, 1);
}
while (randString.Length < 4);
float emSize=(float)width/randString.Length;
Font font = new Font("Arial", emSize, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
Pen pen = new Pen(Color.Silver);
#region 画图片的背景噪音线
int x1,y1,x2,y2;
for (int i = 0; i < 25; i++)
{
x1 = random.Next(image.Width);
y1 = random.Next(image.Height);
x2 = random.Next(image.Width);
y2 = random.Next(image.Height);
g.DrawLine(pen, x1, y1, x2, y2);
}
#endregion
#region 画图片的前景噪音点
for (int i = 0; i < 100; i++)
{
x1 = random.Next(image.Width);
y1 = random.Next(image.Height);
image.SetPixel(x1, y1, Color.FromArgb(random.Next(Int32.MaxValue)));
}
#endregion
g.DrawString(randString, font, Brushes.Red, 2, 2);
g.Dispose();
return image;
}
}
}
using System.Collections.Generic;
using System.Text;
using System.Drawing;
namespace Sooyie.Common
{
/// <summary>
/// 产生随即图片
/// </summary>
public sealed class RandImage
{
private const string RandCharString = "0123456789";
private int width;
private int height;
private int length;
/// <summary>
/// 默认构造函数，生成的图片宽度为48×24，随即字符串字符个数
/// </summary>
public RandImage():this(48,24,4)
{
}
/// <summary>
/// 指定生成图片的宽和高，默认生成图片的字符串长度为4个字符
/// </summary>
/// <param name="width"></param>
/// <param name="height"></param>
public RandImage(int width, int height):this(width,height,4)
{
}
/// <summary>
/// 指定生成图片的宽和高以及生成图片的字符串字符个数
/// </summary>
/// <param name="width"></param>
/// <param name="height"></param>
/// <param name="length"></param>
public RandImage(int width, int height, int length)
{
this.width = width;
this.height = height;
this.length = length;
}
/// <summary>
/// 以默认的大小和默认的字符个数产生图片
/// </summary>
/// <returns></returns>
public Image GetImage()
{
Bitmap image = new Bitmap(width, height);
Graphics g = Graphics.FromImage(image);
g.Clear(Color.White);
string randString = "";
Random random=new Random();
do
{
randString += RandCharString.Substring(random.Next((int)DateTime.Now.Ticks)%RandCharString.Length, 1);
}
while (randString.Length < 4);
float emSize=(float)width/randString.Length;
Font font = new Font("Arial", emSize, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
Pen pen = new Pen(Color.Silver);
#region 画图片的背景噪音线
int x1,y1,x2,y2;
for (int i = 0; i < 25; i++)
{
x1 = random.Next(image.Width);
y1 = random.Next(image.Height);
x2 = random.Next(image.Width);
y2 = random.Next(image.Height);
g.DrawLine(pen, x1, y1, x2, y2);
}
#endregion
#region 画图片的前景噪音点
for (int i = 0; i < 100; i++)
{
x1 = random.Next(image.Width);
y1 = random.Next(image.Height);
image.SetPixel(x1, y1, Color.FromArgb(random.Next(Int32.MaxValue)));
}
#endregion
g.DrawString(randString, font, Brushes.Red, 2, 2);
g.Dispose();
return image;
}
}
}
将图片转换成html资源的aspx页面，这个页面前台没有任何代码，主要后台(.cs)的功能。
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;
using Sooyie.Common;
public partial class CheckImage : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
RandImage randImage=new RandImage();
System.Drawing.Image image = randImage.GetImage();
System.IO.MemoryStream memoryStream = new MemoryStream();
image.Save(memoryStream, ImageFormat.Jpeg);
Response.ClearContent();
Response.ContentType = "image/gif";
Response.BinaryWrite(memoryStream.ToArray());
image.Dispose();
Response.End();
}
}
}
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;
using Sooyie.Common;
public partial class CheckImage : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
RandImage randImage=new RandImage();
System.Drawing.Image image = randImage.GetImage();
System.IO.MemoryStream memoryStream = new MemoryStream();
image.Save(memoryStream, ImageFormat.Jpeg);
Response.ClearContent();
Response.ContentType = "image/gif";
Response.BinaryWrite(memoryStream.ToArray());
image.Dispose();
Response.End();
}
}
}
下面是怎么使用的例子：
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Login.aspx.cs" Inherits="Admin_Login" %>
<!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>后台管理用户登录</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<table border="0" cellpadding="0" cellspacing="0" width="480">
<tr>
<td colspan="2" align="center">
公文管理系统后台登陆</td>
</tr>
<tr>
<td style="width: 83px">
用户名</td><td>
<asp:TextBox ID="txtUserName" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="txtUserName"
ErrorMessage="用户名"></asp:RequiredFieldValidator></td>
</tr>
<tr>
<td style="height: 19px; width: 83px;">
密码</td><td>
<asp:TextBox ID="txtPassword" runat="server" TextMode="Password"></asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ControlToValidate="txtPassword"
ErrorMessage="密码"></asp:RequiredFieldValidator></td>
</tr>
<tr>
<td style="height: 19px; width: 83px;">
校验码</td><td>
<asp:TextBox ID="txtCheckCode" runat="server"></asp:TextBox><img src="CheckImage.aspx" alt="校验码" />
<asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server" ControlToValidate="txtCheckCode"
ErrorMessage="校验码必填"></asp:RequiredFieldValidator></td>
</tr>
<tr>
<td style="width: 83px">
<asp:Button ID="btnLogin" runat="server" Text="登陆" OnClick="btnLogin_Click" /></td><td style="width: 9px">
<input id="Reset1" type="reset" value="清除" /></td>
</tr>
</table>
</div>
<asp:Literal ID="lStatus" runat="server" Visible="False"></asp:Literal>
</form>
</body>
</html>
<!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>后台管理用户登录</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<table border="0" cellpadding="0" cellspacing="0" width="480">
<tr>
<td colspan="2" align="center">
公文管理系统后台登陆</td>
</tr>
<tr>
<td style="width: 83px">
用户名</td><td>
<asp:TextBox ID="txtUserName" runat="server"></asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="txtUserName"
ErrorMessage="用户名"></asp:RequiredFieldValidator></td>
</tr>
<tr>
<td style="height: 19px; width: 83px;">
密码</td><td>
<asp:TextBox ID="txtPassword" runat="server" TextMode="Password"></asp:TextBox>
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ControlToValidate="txtPassword"
ErrorMessage="密码"></asp:RequiredFieldValidator></td>
</tr>
<tr>
<td style="height: 19px; width: 83px;">
校验码</td><td>
<asp:TextBox ID="txtCheckCode" runat="server"></asp:TextBox><img src="CheckImage.aspx" alt="校验码" />
<asp:RequiredFieldValidator ID="RequiredFieldValidator3" runat="server" ControlToValidate="txtCheckCode"
ErrorMessage="校验码必填"></asp:RequiredFieldValidator></td>
</tr>
<tr>
<td style="width: 83px">
<asp:Button ID="btnLogin" runat="server" Text="登陆" OnClick="btnLogin_Click" /></td><td style="width: 9px">
<input id="Reset1" type="reset" value="清除" /></td>
</tr>
</table>
</div>
<asp:Literal ID="lStatus" runat="server" Visible="False"></asp:Literal>
</form>
</body>
</html>
请注意：<img src="CheckImage.aspx" alt="校验码" />这一句就使用了CheckImage.aspx.cs类中的功能，将图片通过HTTP输出。
posted on 2008-05-25 22:11 malaikuangren 阅读(397) 评论(0) 编辑 收藏 举报
