ASP.NET 2.0 HttpHandler实现生成图片验证码(转)

最新推荐文章于 2025-04-08 17:22:17 发布

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最新推荐文章于 2025-04-08 17:22:17 发布

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文章标签： asp.net server textbox login random border

1. 处理程序文件 ValidateImageHandler.ashx代码如下

<% @ WebHandler Language = " C# " Class = " ValidateImageHandler " %>

using System;

using System.Web;

using System.Web.SessionState;

using System.Drawing;

using System.Drawing.Imaging;

using System.Text;

/**/ /// <summary>

/// ValidateImageHandler 生成网站验证码功能

/// </summary>

public class ValidateImageHandler : IHttpHandler, IRequiresSessionState

{

int intLength = 5; //长度

string strIdentify = "Identify"; //随机字串存储键值，以便存储到Session中

public ValidateImageHandler()

{

}

/**//// <summary>

/// 生成验证图片核心代码

/// </summary>

/// <param name="hc"></param>

public void ProcessRequest(HttpContext hc)

{

//设置输出流图片格式

hc.Response.ContentType = "image/gif";

Bitmap b = new Bitmap(200, 60);

Graphics g = Graphics.FromImage(b);

g.FillRectangle(new SolidBrush(Color.YellowGreen), 0, 0, 200, 60);

Font font = new Font(FontFamily.GenericSerif, 48, FontStyle.Bold, GraphicsUnit.Pixel);

Random r = new Random();

//合法随机显示字符列表

string strLetters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";

StringBuilder s = new StringBuilder();

//将随机生成的字符串绘制到图片上

for (int i = 0; i < intLength; i++)

{

s.Append(strLetters.Substring(r.Next(0, strLetters.Length - 1), 1));

g.DrawString(s[s.Length - 1].ToString(), font, new SolidBrush(Color.Blue), i * 38, r.Next(0, 15));

}

//生成干扰线条

Pen pen = new Pen(new SolidBrush(Color.Blue), 2);

for (int i = 0; i < 10; i++)

{

g.DrawLine(pen, new Point(r.Next(0, 199), r.Next(0, 59)), new Point(r.Next(0, 199), r.Next(0, 59)));

}

b.Save(hc.Response.OutputStream, ImageFormat.Gif);

hc.Session[strIdentify] = s.ToString(); //先保存在Session中，验证与用户输入是否一致

hc.Response.End();

}

/**//// <summary>

/// 表示此类实例是否可以被多个请求共用(重用可以提高性能)

/// </summary>

public bool IsReusable

{

get

{

return true;

}

2.前台代码

@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_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 > ImageValidateCode_HttpHandler </ title >

</ head >

< body >

< form id ="form1" runat ="server" >

< div >

  < br />

< asp:Login ID ="Login1" runat ="server" BackColor ="#EFF3FB" BorderColor ="#B5C7DE" BorderPadding ="4"

BorderStyle ="Solid" BorderWidth ="1px" Font-Names ="Verdana" Font-Size ="0.8em"

ForeColor ="#333333" OnAuthenticate ="Login1_Authenticate" >

< TitleTextStyle BackColor ="#507CD1" Font-Bold ="True" Font-Size ="0.9em" ForeColor ="White" />

< InstructionTextStyle Font-Italic ="True" ForeColor ="Black" />

< TextBoxStyle Font-Size ="0.8em" />

< LoginButtonStyle BackColor ="White" BorderColor ="#507CD1" BorderStyle ="Solid" BorderWidth ="1px"

Font-Names ="Verdana" Font-Size ="0.8em" ForeColor ="#284E98" />

< LayoutTemplate >

< table border ="0" cellpadding ="4" cellspacing ="0" style ="border-collapse: collapse" >

< tr >

< td style ="width: 292px" >

< table border ="0" cellpadding ="0" >

< tr >

< td align ="center" colspan ="2" style ="font-weight: bold; font-size: 0.9em; color: white;

background-color: #507cd1" >

</ tr >

< tr >

< td align ="left" style ="width: 84px; height: 31px;" >

< asp:Label ID ="UserNameLabel" runat ="server" AssociatedControlID ="UserName" > 用户名: </ asp:Label ></ td >

< td style ="height: 31px; width: 215px;" >

< asp:TextBox ID ="UserName" runat ="server" Font-Size ="0.8em" Width ="113px" ></ asp:TextBox >

< asp:RequiredFieldValidator ID ="UserNameRequired" runat ="server" ControlToValidate ="UserName"

ErrorMessage ="必须填写“用户名”。" ToolTip ="必须填写“用户名”。" ValidationGroup ="Login1" > * </ asp:RequiredFieldValidator >

</ td >

</ tr >

< tr >

< td align ="left" style ="width: 84px" >

< asp:Label ID ="PasswordLabel" runat ="server" AssociatedControlID ="Password" > 密码: </ asp:Label ></ td >

< td style ="width: 215px" >

< asp:TextBox ID ="Password" runat ="server" Font-Size ="0.8em" TextMode ="Password" ></ asp:TextBox >

< asp:RequiredFieldValidator ID ="PasswordRequired" runat ="server" ControlToValidate ="Password"

ErrorMessage ="必须填写“密码”。" ToolTip ="必须填写“密码”。" ValidationGroup ="Login1" > * </ asp:RequiredFieldValidator >

</ td >

</ tr >

< tr >

< td style ="width: 84px; height: 4px;" align ="left" >

验证码: </ td >

< td valign ="middle" style ="height: 31px; width: 215px;" align ="left" >

< asp:TextBox ID ="TextBox1" runat ="server" Font-Size ="0.8em" TextMode ="Password" ></ asp:TextBox >  

< img width ="100px" height ="25px" src ="ValidateImageHandler.ashx" /></ td >

</ tr >

< tr >

< td align ="left" colspan ="2" style ="color: red" >

< asp:CheckBox ID ="RememberMe" runat ="server" Text ="下次记住我。" />   </ td >

</ tr >

< tr >

< td align ="right" colspan ="2" >

< asp:Button ID ="LoginButton" runat ="server" BackColor ="White" BorderColor ="#507CD1"

BorderStyle ="Solid" BorderWidth ="1px" CommandName ="Login" Font-Names ="Verdana"

Font-Size ="0.8em" ForeColor ="#284E98" Text ="登录" ValidationGroup ="Login1" />

</ td >

</ tr >

</ table >

</ td >

</ tr >

</ table >

</ LayoutTemplate >

</ asp:Login >

</ div >

</ form >

</ body >

</ html >