c#绘制验证码

public class ValidateCode
    {

        public void CerateValidateGraphic(HttpContext context)
        {
            //0.0得到字符串
            string code = GetVcode(5);
            //0.1将验证码保存在Session["对象命名"]中
            context.Session["Code"] = code;

            //1.0准备一个画板对象装载子类对象绘画纸并确定绘画纸的长宽
            using (Bitmap img = new Bitmap((int)Math.Ceiling(code.Length * 13.0), 25))
            {
                //2.0给画板配备一个画家
                using (Graphics g = Graphics.FromImage(img))
                {
                    //将验证码的背景变为白色（默认为黑色）
                    g.Clear(Color.White);

                    //绘制边框(即绘图范围),Pens.Black边框宽度
                    g.DrawRectangle(Pens.Black, 0, 0, img.Width - 1, img.Height - 1);

                    //画一些干扰点
                    DrawPoint(g, img, 30);

                    //话图片的前景噪音点
                    for (int i = 0; i < 100; i++)
                    {
                        int x = r.Next(img.Width);
                        int y = r.Next(img.Height);
                        img.SetPixel(x, y, Color.FromArgb(r.Next()));
                    }


                    //3.0将验证码划到图片上
                    g.DrawString(code, new Font("微软雅黑", 12, FontStyle.Italic | FontStyle.Strikeout), Brushes.Red, 0, 0);

                }

                //3.0将图片保存到Response的输出流中
                img.Save(context.Response.OutputStream, ImageFormat.Jpeg);

            }
        }



        /// 

        /// 绘制干扰线
        /// 
        /// 画家对象
        /// 画板对象
        /// 干扰线数量
        public void DrawPoint(Graphics g, Image img, int number)
        {
            //得到X,Y的坐标
            int x;
            int y;
            int x2;
            int y2;

            //随机生成x和y的数据，但不能跑出绘画纸范围
            for (int i = 0; i < number; i++)
            {
                x = r.Next(0, img.Width);
                x2 = r.Next(0, img.Width);
                y = r.Next(0, img.Height);
                y2 = r.Next(0, img.Height);

                //连接两点，Pens.Black线宽
                g.DrawLine(new Pen(Color.Silver), x, y, x2, y2);
            }
        }

        Random r = new Random();

        /// 

        /// 得到随机生成的验证码
        /// 
        /// 验证码长度
        /// 
        public string GetVcode(int number)
        {
            //准备一个数据源
            char[] arr =
                {
                '0','1','2','3','4','5','6','7','8','9',
                'q','w','e','r','t','y','u','i','o','p',
                'a','s','d','f','g','h','j','k','l','z',
                'x','c','v','b','n','m','Q','W','E','R',
                'T','Y','U','I','O','P','A','S','D','F',
                'G','H','J','K','L','Z','X','C','V','B',
                'N','M'};
            //  创建一个验证码字符串

            string code = null;
            for (int i = 0; i < number; i++)
            {
                //得到数组的索引
                int index = r.Next(0, arr.Length);//包括0，不包括arr.lenght
                code += arr[index];
            }

            return code;
        }


        //c# MVC升级版
        /// 

        /// 创建验证码图片
        /// 
        /// 
        public byte[] CreateValidateGraphic(string code)
        {
            //0.0得到字符串

            //1.0准备一个画板对象装载子类对象绘画纸并确定绘画纸的长宽
            using (Bitmap img = new Bitmap((int)Math.Ceiling(code.Length * 13.0), 25))
            {
                //2.0给画板配备一个画家
                using (Graphics g = Graphics.FromImage(img))
                {
                    //将验证码的背景变为白色（默认为黑色）
                    g.Clear(Color.White);

                    //绘制边框(即绘图范围),Pens.Black边框宽度
                    g.DrawRectangle(Pens.Black, 0, 0, img.Width - 1, img.Height - 1);

                    //画一些干扰点
                    //DrawPoint(g, img, 30);

                    //话图片的前景噪音点
                    for (int i = 0; i < 100; i++)
                    {
                        int x = r.Next(img.Width);
                        int y = r.Next(img.Height);
                        img.SetPixel(x, y, Color.FromArgb(r.Next()));
                    }


                    //3.0将验证码划到图片上
                    g.DrawString(code, new Font("微软雅黑", 12, FontStyle.Italic | FontStyle.Strikeout), Brushes.Red, 0, 0);

                }

                //保存图片数据
                MemoryStream stream = new MemoryStream();
                //将图片以流的形式存储为jgep格式
                img.Save(stream, ImageFormat.Jpeg);
                //输出图片流
                return stream.ToArray();

            }
        }
    }

/// 

        /// 生成验证码
        /// 
        /// 
        public ActionResult ShowValidateCode()
        {
            ValidateCode validateCode = new ValidateCode();
            string code = validateCode.GetVcode(5);//产生验证码
            Session["validateCode"] = code;//将验证码数据存储至session中
            byte[] buffer = validateCode.CreateValidateGraphic(code);//将验证码画到画布上
            return File(buffer, "image/jpeg");//传输图片数据
        }

将验证码图片数据传输至前端