一个简单的Web验证码程序

来源：互联网发布：淘宝信用卡在哪里开通编辑：程序博客网时间：2024/06/05 22:50

建立一个Web窗体程序Captcha.aspx,其代码如下:

前台文件 Captcha.aspx：

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

后台文件 Captcha.aspx.cs：

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.Drawing.Design; using System.Drawing;public partial class Captcha : System.Web.UI.Page{    protected void Page_Load(object sender, EventArgs e)    {        this.CreateImage();        this.Response.End();    }    /// <summary>    /// 字符串    /// </summary>    private string GetRand()    {        #region 字符串        string str = "";        //数字        for (int i = 0; i < 10; i++)        {            str += ((char)((char)'0' + (char)i)).ToString();        }        //字母        for (int i = 0; i < 26; i++)        {            str += ((char)((char)'a' + (char)i)).ToString();            str += ((char)((char)'A' + (char)i)).ToString();        }        #endregion        #region 重新排列字符串的顺序        Random rand = new Random();        string newStr = "";                do        {            if (str == null || str.Length < 1)            {                break;            }            int i = rand.Next(0, str.Length);                        newStr += str[i].ToString();            str = str.Remove(i,1);                    } while (true);        #endregion        str = newStr.Substring(rand.Next(0, newStr.Length - 4), 4);        this.Session.Add("CaptchaCode", str);        return str;    }    /// <summary>    /// 生成图片    /// </summary>    private void CreateImage()    {        string randCode = GetRand();        if (randCode == null || randCode.Trim() == String.Empty)        {            return;        }        System.Drawing.Bitmap image = new System.Drawing.Bitmap(80, 22);        Graphics g = Graphics.FromImage(image);        try        {            //生成随机生成器             Random random = new Random();            //清空图片背景色             g.Clear(Color.White);            //画图片的背景噪音线             for (int i = 0; i < 25; i++)            {                int x1 = random.Next(image.Width);                int x2 = random.Next(image.Width);                int y1 = random.Next(image.Height);                int y2 = random.Next(image.Height);                g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);            }            Font font = new System.Drawing.Font("Arial", 15, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));            System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width - 20, image.Height), Color.Orange, Color.DarkRed, 1.2f, true);            g.DrawString(randCode, font, brush, 12, 0);                        //画图片的前景噪音点             for (int i = 0; i < 100; i++)            {                int x = random.Next(image.Width);                int y = random.Next(image.Height);                image.SetPixel(x, y, Color.FromArgb(random.Next()));            }            //画图片的边框线             g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);                        System.IO.MemoryStream ms = new System.IO.MemoryStream();                        image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);            Response.ClearContent();            Response.ContentType = "image/Gif";            Response.BinaryWrite(ms.ToArray());        }        finally        {            //注销资源            g.Dispose();            image.Dispose();        }    }}

注意：如果您的网页文件不是Captcha.aspx，请替换文件中的Captcha；如果您的文件类型不是网页文件（.aspx），请替换Response

将验证码图像<img style="width:80px; height:60px; border:0px" src="{src}" /> 中的{src}替换为Captcha.aspx的网址就OK了