• λ我爱Aspx >> Asp.Net >> ASP.NET 2.0 HttpHandler实现生成图片验证码(示例代码下载)

    • ASP.NET 2.0 HttpHandler实现生成图片验证码(示例代码下载)

  • :KeNtEr' Blog  Դ:csdn blog  :2007-9-5 16:05:24  ؼ:ASP.NET 2.0 HttpHandler实现生成图片验证码(示例代码下载)
  • 学习整理了一下
     
    (一).功能
     
          用HttpHandler实现图片验证码
     
         
     
    (二).代码如下
     
     1. 处理程序文件 ValidateImageHandler.ashx代码如下
     
     1 <%@ WebHandler Language="C#" Class="ValidateImageHandler" %>
     2 
     3 using System;
     4 using System.Web;
     5 using System.Web.SessionState;
     6 using System.Drawing;
     7 using System.Drawing.Imaging;
     8 using System.Text;
     9 
    10 /// <summary>
    11 /// ValidateImageHandler 生成网站验证码功能
    12 /// </summary>
    13 public class ValidateImageHandler : IHttpHandler, IRequiresSessionState
    14 {
    15     int intLength = 5;               //长度
    16     string strIdentify = "Identify"; //随机字串存储键值，以便存储到Session中
    17     public ValidateImageHandler()
    18     {        
    19     }
    20 
    21     /// <summary>
    22     ///  生成验证图片核心代码
    23     /// </summary>
    24     /// <param name="hc"></param>
    25     public void ProcessRequest(HttpContext hc)
    26     {
    27         //设置输出流图片格式
    28         hc.Response.ContentType = "image/gif";
    29         
    30         Bitmap b = new Bitmap(200, 60);
    31         Graphics g = Graphics.FromImage(b);
    32         g.FillRectangle(new SolidBrush(Color.YellowGreen), 0, 0, 200, 60);
    33         Font font = new Font(FontFamily.GenericSerif, 48, FontStyle.Bold, GraphicsUnit.Pixel);
    34         Random r = new Random();
    35 
    36         //合法随机显示字符列表
    37         string strLetters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
    38         StringBuilder s = new StringBuilder();
    39         
    40         //将随机生成的字符串绘制到图片上
    41         for (int i = 0; i < intLength; i++)
    42         {
    43             s.Append(strLetters.Substring(r.Next(0, strLetters.Length - 1), 1));
    44             g.DrawString(s[s.Length - 1].ToString(), font, new SolidBrush(Color.Blue), i * 38, r.Next(0, 15));
    45         }
    46 
    47         //生成干扰线条
    48         Pen pen = new Pen(new SolidBrush(Color.Blue), 2);
    49         for (int i = 0; i < 10; i++)
    50         {
    51             g.DrawLine(pen, new Point(r.Next(0, 199), r.Next(0, 59)), new Point(r.Next(0, 199), r.Next(0, 59)));
    52         }
    53         b.Save(hc.Response.OutputStream, ImageFormat.Gif);
    54         hc.Session[strIdentify] = s.ToString(); //先保存在Session中，验证与用户输入是否一致
    55         hc.Response.End();
    56    
    57     }
    58     
    59     /// <summary>
    60     /// 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)
    61     /// </summary>
    62     public bool IsReusable
    63     {
    64         get
    65         {
    66             return true;
    67         }
    68     }
    69 }
    70 

     2. 前台页面代码

     1 <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">
     2             <TitleTextStyle BackColor="#507CD1" Font-Bold="True" Font-Size="0.9em" ForeColor="White" />
     3             <InstructionTextStyle Font-Italic="True" ForeColor="Black" />
     4             <TextBoxStyle Font-Size="0.8em" />
     5             <LoginButtonStyle BackColor="White" BorderColor="#507CD1" BorderStyle="Solid" BorderWidth="1px"
     6                 Font-Names="Verdana" Font-Size="0.8em" ForeColor="#284E98" />
     7             <LayoutTemplate>
     8                 <table border="0" cellpadding="4" cellspacing="0" style="border-collapse: collapse">
     9                     <tr>
    10                         <td style="width: 292px">
    11                             <table border="0" cellpadding="0">
    12                                 <tr>
    13                                     <td align="center" colspan="2" style="font-weight: bold; font-size: 0.9em; color: white;
    14                                         background-color: #507cd1">
    15                                         登录</td>
    16                                 </tr>
    17                                 <tr>
    18                                     <td align="left" style="width: 84px; height: 31px;">
    19                                         <asp:Label ID="UserNameLabel" runat="server" AssociatedControlID="UserName">用户名:</asp:Label></td>
    20                                     <td style="height: 31px; width: 215px;">
    21                                         <asp:TextBox ID="UserName" runat="server" Font-Size="0.8em" Width="113px"></asp:TextBox>
    22                                         <asp:RequiredFieldValidator ID="UserNameRequired" runat="server" ControlToValidate="UserName"
    23                                             ErrorMessage="必须填写“用户名”。" ToolTip="必须填写“用户名”。" ValidationGroup="Login1">*</asp:RequiredFieldValidator>
    24                                     </td>
    25                                 </tr>
    26                                 <tr>
    27                                     <td align="left" style="width: 84px">
    28                                         <asp:Label ID="PasswordLabel" runat="server" AssociatedControlID="Password">密码:</asp:Label></td>
    29                                     <td style="width: 215px">
    30                                         <asp:TextBox ID="Password" runat="server" Font-Size="0.8em" TextMode="Password"></asp:TextBox>
    31                                         <asp:RequiredFieldValidator ID="PasswordRequired" runat="server" ControlToValidate="Password"
    32                                             ErrorMessage="必须填写“密码”。" ToolTip="必须填写“密码”。" ValidationGroup="Login1">*</asp:RequiredFieldValidator>
    33                                     </td>
    34                                 </tr>
    35                                 <tr>
    36                                     <td style="width: 84px; height: 4px;" align="left">
    37                                         验证码:</td>
    38                                     <td valign="middle" style="height: 31px; width: 215px;" align="left">
    39                                         <asp:TextBox ID="TextBox1" runat="server" Font-Size="0.8em" TextMode="Password"></asp:TextBox>&nbsp;
    40                                         
                                     <img width="100px" height="25px" src="ValidateImageHandler.ashx"/>
                                            </td>
    41                                 </tr>
    42                                 <tr>
    43                                     <td align="left" colspan="2" style="color: red">
    44                                         <asp:CheckBox ID="RememberMe" runat="server" Text="下次记住我。" />&nbsp;</td>
    45                                 </tr>
    46                                 <tr>
    47                                     <td align="right" colspan="2">
    48                                         <asp:Button ID="LoginButton" runat="server" BackColor="White" BorderColor="#507CD1"
    49                                             BorderStyle="Solid" BorderWidth="1px" CommandName="Login" Font-Names="Verdana"
    50                                             Font-Size="0.8em" ForeColor="#284E98" Text="登录" ValidationGroup="Login1" />
    51                                     </td>
    52                                 </tr>
    53                             </table>
    54                         </td>
    55                     </tr>
    56                 </table>
    57             </LayoutTemplate>
    58         
    59         </asp:Login>
    60 

      3.这里因为使用的是默认 *.asah处理文件类型，在machine.config文件中已经有此类型的默认注册，

     因为这里不需要注册
     
    1 <httpHandlers>
    2   <add verb="*" path="*.asah" type="System.Web.UI.SimpleHandlerFactory" />
    3 </httpHandlers>
    4 

     注意:

    1.再注册一下也不会出错，会覆盖machine.config文件配置

    2.如果在同一个配置文件中注册多次，默认后者也会覆盖前者.

    3.如果其它格式(系统默认没有注册)的，务必要在Web.config文件中注册一下.

     
    (三).示例代码下载
       
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