C#验证码公用类

来源：互联网发布：linux 装网卡编辑：程序博客网时间：2024/05/16 09:09
  protected void GetCode()      {            System.Random rand = new Random();            int len = 4;    //这里设置验证码长度，我的定义为4，最近见到些网上上有随机4，5，6位的。这里自己写个随机函数就可以了。             //char[] chars = "0123456789ABCDEFGHJKMNOPQRSTUVWXYZ".ToCharArray();            char[] chars = "123456789ABCDEFGHJKMNPQRSTUVWXYZ".ToCharArray();            System.Text.StringBuilder myStr = new System.Text.StringBuilder();            for (int iCount = 0; iCount < len; iCount++)            {                myStr.Append(chars[rand.Next(chars.Length)]);            }            string text = myStr.ToString();            // 保存验证码到 session 中以便其他模块使用             Session["code"] = text;   //这里你的登陆页面判断输入验证码是否正确，if (txtCode.text == Session["code"]) 正确读库检索User/Password,不正确弹窗。自己写            Size ImageSize = Size.Empty;            Font myFont = new Font("MS Sans Serif", 14, FontStyle.Bold);  //绘制在验证图片上的文字大小            // 计算验证码图片大小             using (Bitmap bmp = new Bitmap(5, 5))            {                using (Graphics g = Graphics.FromImage(bmp))                {                    SizeF size = g.MeasureString(text, myFont, 10000);                    ImageSize.Width = (int)size.Width + 3;                    ImageSize.Height = (int)size.Height + 3;                }            }            // 创建验证码图片             using (Bitmap bmp = new Bitmap(ImageSize.Width, ImageSize.Height))            {                // 绘制验证码文本                 using (Graphics g = Graphics.FromImage(bmp))                {                    g.Clear(Color.White);                    using (StringFormat f = new StringFormat())                    {                        f.Alignment = StringAlignment.Near;                        f.LineAlignment = StringAlignment.Center;                        f.FormatFlags = StringFormatFlags.NoWrap;                        g.DrawString(text, myFont, Brushes.Black, new RectangleF(0, 0, ImageSize.Width, ImageSize.Height), f);                    }//using                 }//using                 // 制造杂点 杂点面积占图片面积的 20%                 int num = ImageSize.Width * ImageSize.Height * 20 / 100;                for (int iCount = 0; iCount < num; iCount++)                {                    // 在随机的位置使用随机的颜色设置图片的像素                     int x = rand.Next(ImageSize.Width);                    int y = rand.Next(ImageSize.Height);                    int r = rand.Next(255);                    int g = rand.Next(255);                    int b = rand.Next(255);                    Color c = Color.FromArgb(r, g, b);                    bmp.SetPixel(x, y, c);                }//for                 // 输出图片                 System.IO.MemoryStream ms = new System.IO.MemoryStream();                bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Png);                this.Response.ContentType = "image/png";                ms.WriteTo(this.Response.OutputStream);                ms.Close();            }//using             myFont.Dispose();        }
阅读全文
0 0