生成验证码

来源：互联网发布：查看淘宝隐形降权编辑：程序博客网时间：2024/06/05 15:16

后台:

protected void Page_Load(object sender, EventArgs e)        {            createCheckCodeImage(generateCheckCode(4));        }        /// <summary>        /// 生成验证码        /// </summary>        /// <param name="codeNum"></param>        /// <returns></returns>        private string generateCheckCode(int codeNum)        {            int ranNum;            char[] cArray = new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };            string checkCode = string.Empty;            Random random = new Random();            for (int i = 0; i < codeNum; i++)            {                ranNum = random.Next(62);                checkCode += cArray[ranNum];            }            Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));            Session["ValidateCode"] = checkCode.ToLower();            return checkCode;        }        /// <summary>        /// 生成背景图片        /// </summary>        /// <param name="checkCode"></param>        private void createCheckCodeImage(string checkCode)        {            if (checkCode == null || checkCode.Trim() == string.Empty)                return;            Bitmap image = new Bitmap((int)Math.Ceiling(checkCode.Length * 12.5), 22);            Graphics g = Graphics.FromImage(image);            try            {                Random random = new Random();                g.Clear(Color.White);                //画背景干扰线                for (int i = 0; i < 2; 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.OrangeRed), x1, y1, x2, y2);                }                Font font = new Font("Arial", 13, (FontStyle.Bold));                LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.DarkGreen, Color.DarkOrchid, 1.2f, true);                g.DrawString(checkCode, font, brush, 2, 2);                //画图片前景噪音点                for (int i = 0; i < 30; i++)                {                    int x = random.Next(image.Width);                    int y = random.Next(image.Height);                    image.SetPixel(x, y, Color.FromArgb(random.Next()));                }                //画图片边框线                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            {                g.Dispose();                image.Dispose();            }        }

要调用的页面:

js:

function CetCode() {             document.getElementById("txtYanZen").src = "Validate.aspx";             document.forms[0].submit();         }

aspx:

  <img src="Validate.aspx" alt="验证码" id="YanZen"/>                   <a href="javascript:CetCode()">看不清换一张</a>