public class HomeController : Controller    {        public byte[] Test()        {            Random r = new Random((int)DateTime.Now.Ticks);            int startChar = 64;            string result = String.Empty;            for (int i = 0; i < 4; i++)            {                int t = r.Next(1, 27);                result += Convert.ToChar(t + startChar);            }            var image = new Bitmap((int)Math.Ceiling(result.Length * 15.0), 22);            var g = Graphics.FromImage(image);            try            {                var random = new Random();                g.Clear(Color.White);                for (int i = 0; i < 25; i++)                {                    var x1 = random.Next(image.Width);                    var x2 = random.Next(image.Width);                    var y1 = random.Next(image.Height);                    var y2 = random.Next(image.Height);                    g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);                }                Font font = new Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic));                var brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height),                Color.Blue, Color.DarkRed, 1.2f, true);                g.DrawString(result, font, brush, 3, 2);                //画图片的前景干扰点                for (var i = 0; i < 100; i++)                {                    var x = random.Next(image.Width);                    var 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);                //保存图片数据                var stream = new MemoryStream();                image.Save(stream, ImageFormat.Jpeg);                //输出图片流                return stream.ToArray();            }            finally            {                g.Dispose();                image.Dispose();            }        }        //        // GET: /Home/        public ActionResult Index()        {            return View();        }        public ActionResult GenerateImage()        {            return File(Test(), @"image/gif");        }    }