c# 自己写验证码

来源：互联网发布：小白菜软件编辑：程序博客网时间：2024/06/13 08:30

效果

后台代码

protected override void OnPreInit(EventArgs e)        {            //字符 去掉了 o0 i1l            string str = "A,B,C,D,E,F,G,H,G,K,M,N,P,Q,R,S,T,U,V,W,X,Y,Z,2,3,4,5,6,7,8,9";            //颜色            Color[] cs = new Color[] { Color.Red, Color.Green, Color.Black, Color.Blue, Color.Purple };            //字体            string[] fs = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" };            //字体大小            int[] size = new int[] { 16, 18, 20 };            //字体样式            FontStyle[] _fs = new FontStyle[] { FontStyle.Bold, FontStyle.Italic, FontStyle.Regular };            Random ram = new Random();            Bitmap img = new Bitmap(80, 25);            Graphics g = Graphics.FromImage(img);            //清空图片            g.Clear(Color.White);            //画干扰线            for (int i = 1; i <= 5; i++)            {                int x1 = ram.Next(img.Width);                int y1 = ram.Next(img.Height);                int x2 = ram.Next(img.Width);                int y2 = ram.Next(img.Height);                Pen p = new Pen(cs[ram.Next(cs.Length)]);                g.DrawLine(p, x1, y1, x2, y2);            }            //画字符            string[] array = str.Split(',');            string vcode = string.Empty;            for (int i = 1; i <= 4; i++)            {                Font f = new Font(fs[ram.Next(fs.Length)], size[ram.Next(size.Length)], _fs[ram.Next(_fs.Length)]);                Brush b = new SolidBrush(cs[ram.Next(cs.Length)]);                string temp = array[ram.Next(array.Length)];                vcode += temp.ToLower();                if (ram.Next(9) % 2 == 0)                {                    g.DrawString(temp, f, b, new Point(20 * (i - 1) + 0, 0));                }                else                {                    g.DrawString(temp.ToLower(), f, b, new Point(20 * (i - 1) + 0, 0));                }            }            //画噪点            for (int i = 1; i <= 30; i++)            {                int x = ram.Next(img.Width);                int y = ram.Next(img.Height);                Color clr = cs[ram.Next(cs.Length)];                img.SetPixel(x, y, clr);            }            //将验证码的值保存            Response.Cookies.Add(new HttpCookie("9FDFFFADBEF1A3D9612D39754765D442", StringHelper.EncryptAES(vcode)));            //设置页面无缓存            Response.Buffer = true;            Response.ExpiresAbsolute = System.DateTime.Now.AddSeconds(-1);            Response.Expires = 0;            Response.CacheControl = "no-cache";            Response.AppendHeader("Pragma", "No-Cache");            //写入文件流            System.IO.MemoryStream ms = new System.IO.MemoryStream();            img.Save(ms, System.Drawing.Imaging.ImageFormat.Png);            Response.Cache.SetNoStore();            Response.ClearContent();            Response.ContentType = "image/Jpeg";            Response.BinaryWrite(ms.ToArray());            //释放            g.Dispose();            img.Dispose();            Response.End();        }

前台调用

<img src="VCode.aspx" alt="看不清，换一个" title="看不清，换一个" style="cursor:pointer;" onclick="javascript:this.src='VCode.aspx?vc='+Math.random();" />