点滴积累【C#】---验证码，ajax提交

效果：

思路：

借用ashx文件创建四位验证，首先生成四位随机数字。然后创建画布，再将创建好的验证码存入session,然后前台进行button按钮将文本框中的值进行ajax请求到后台，和session中的验证码进行对比，成功返回true,失败返回false.

代码：

【前台】

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

 <!DOCTYPE html>

 <html xmlns="http://www.w3.org/1999/xhtml">

 <head runat="server">

     <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />

     <title>青苹果验证码例子</title>

     <script src="jquery-1.3.2.min.js"></script>

     <script type="text/javascript">

         //切换验证码

         function ToggleCode(obj, codeurl) {

             $("#" + obj).attr("src", codeurl + "?time=" + Math.random());

         }

         //ajax提交后台验证

         function postAjax() {

             var VerifyCodeValue = $("#txtVerifyCode").val();

             $.ajax({

                 type: 'post',

                 dataType: "text",

                 url: "verifycodeDemo.aspx",

                 data: "action=comparison&VerifyCode=" + VerifyCodeValue,

                 cache: false,

                 async: false,

                 success: function (msg) {

                     if (msg == "false") {

                         alert("验证失败!sorry,青苹果");

                         ToggleCode("Verify_codeImag", "VerifyCode.ashx");

                         $("#txtVerifyCode").val("");

                     }

                     else {

                         alert("验证成功！hello,青苹果!");

                     }

                 }

             });

         }

     </script>

 </head>

 <body>

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

         <div>

             <input type="text" id="txtVerifyCode" />

             <img src="VerifyCode.ashx" id="Verify_codeImag" alt="点击切换验证码" style="CURSOR: pointer" width="65" height="25" title="点击切换验证码" onclick="ToggleCode(this.id, 'VerifyCode.ashx');return false;" />

             <input type="button" value="青苹果验证码" onclick="postAjax()" />

         </div>

     </form>

 </body>

 </html>

【后台】

 using System;

 using System.Collections.Generic;

 using System.Linq;

 using System.Web;

 using System.Web.UI;

 using System.Web.UI.WebControls;

 namespace verifycodeDemo

 {

     public partial class verifycodeDemo : System.Web.UI.Page

     {

         protected void Page_Load(object sender, EventArgs e)

         {

             string action = Request.Params["action"];

             string VerifyCodeValue = Request.Params["VerifyCode"];

             if (action == "comparison")

             {

                 string Msg = "true";

                 //对session中存储的验证码对比

                 if (HttpContext.Current.Session["dt_session_code"] == null || VerifyCodeValue.ToLower() != HttpContext.Current.Session["dt_session_code"].ToString().ToLower())

                 {

                     Msg = "false";//验证码输入不正确

                 }

                 Response.Write(Msg);

                 Response.End();

             }

         }

     }

 }

【ashx文件】

 using System;

 using System.Collections.Generic;

 using System.Drawing;

 using System.Drawing.Imaging;

 using System.IO;

 using System.Linq;

 using System.Web;

 using System.Web.SessionState;

 namespace ESoftMS.Web.Frame

 {

     /// <summary>

     /// VerifyCode 的摘要说明 青苹果(www.cnblogs.com/xinchun)

     /// </summary>

     public class VerifyCode : IHttpHandler, IRequiresSessionState

     {

         public void ProcessRequest(HttpContext context)

         {

             int codeW = ;

             int codeH = ;

             int fontSize = ;

             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.Brown, Color.DarkBlue };

             //字体列表，用于验证码

             string[] font = { "Times New Roman", "Verdana", "Arial", "Gungsuh", "Impact" };

             //验证码的字符集，去掉了一些容易混淆的字符

             char[] character = { '', '', '', '', '', '', '', 'a', 'b', 'd', 'e', 'f', 'h', 'k', 'm', 'n', 'r', 'x', 'y', '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 = ; i < ; i++)

             {

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

             }

             //写入Session

             context.Session["dt_session_code"] = chkCode;

             //创建画布

             Bitmap bmp = new Bitmap(codeW, codeH);

             Graphics g = Graphics.FromImage(bmp);

             g.Clear(Color.White);

             //画噪线

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

             {

                 int x1 = rnd.Next(codeW);

                 int y1 = rnd.Next(codeH);

                 int x2 = rnd.Next(codeW);

                 int y2 = rnd.Next(codeH);

                 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 = ; i < chkCode.Length; i++)

             {

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

                 Font ft = new Font(fnt, fontSize);

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

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

             }

             ////画噪点

             //for (int i = 0; i < 1; 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

             context.Response.Buffer = true;

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

             context.Response.Expires = ;

             context.Response.CacheControl = "no-cache";

             context.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);

                 context.Response.ClearContent();

                 context.Response.ContentType = "image/Gif";

                 context.Response.BinaryWrite(ms.ToArray());

             }

             catch (Exception)

             {

             }

             finally

             {

                 g.Dispose();

                 bmp.Dispose();

             }

         }

         public bool IsReusable

         {

             get

             {

                 return false;

             }

         }

     }

 }

Demo下载：

http://files.cnblogs.com/xinchun/verifycodeDemo.rar

巴特西

点滴积累【C#】---验证码，ajax提交

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