BinaryWrite方法输出二进制图像验证码

protected void Page_Load(object sender, EventArgs e)
        {
            string checkCode = "陌上花开，可缓缓归矣";
            //创建画板
            System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 20.5)), 22);
            Graphics g = Graphics.FromImage(image);//创建Graphics对象
            try
            {
                Random random = new Random();//生成随机生成器
                g.Clear(Color.White);//清空图片背景色
                for (int i = 0; i < 2; i++)//画图片的背景噪音线
                {
                    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.Black), x1, y1, x2, y2);
                }
                Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold));
                System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Gray, Color.DarkBlue, 1.2f, true);
                g.DrawString(checkCode, font, brush, 2, 2);
                for (int i = 0; i < 100; i++)//画图片的前景噪音点
                {
                    int x = random.Next(image.Width);
                    int y = random.Next(image.Height);
                    image.SetPixel(x, y, Color.FromArgb(random.Next()));
                }
                g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
                System.IO.MemoryStream ms = new System.IO.MemoryStream();//画图片的边框线
                image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
                Response.ClearContent();
                Response.ContentType = "image/Gif";
                Response.BinaryWrite(ms.ToArray());
            }
            finally
            {
                g.Dispose();
                image.Dispose();
            }
        }

运行效果：