生成验证码-优快云博客

本文介绍了一种生成包含字母和数字的随机验证码的方法，并详细展示了如何通过C#编程创建带有背景线条和随机噪点的验证码图片。

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Code
        public string RandomWords(int maxLength)
        {
            string words = "1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,I,J,K,L,M,N,P,Q,R,S,T,U,V,W,X,Y,Z";
            string[] wordsArr = words.Split(new char[] { ',' });
            Random random = new Random();
            string code = string.Empty;
            for (int i = 0; i < maxLength; i++)
            {
                code += wordsArr[random.Next(0, 33)];
            }
            return code;
        }

        public void CreateImage(string content)
        {
            //图片长度
            int imageWidth = (int)(content.Length * 15);
            //创建位图
            Bitmap image = new Bitmap(imageWidth, 23);
            //根据图片大小生成画板
            Graphics grap = Graphics.FromImage(image);
            //字体
            Font font = new Font("Arial", 14, FontStyle.Italic);
            //笔刷
            Brush brush = new SolidBrush(Color.FromArgb(204, 0, 240));
            //生成画板背景
            grap.Clear(Color.FromArgb(235,235,235));
            //画笔
            Pen pen = new Pen(Color.White,1);
            //生成三条背景线
            Random random = new Random();
            for(int i = 0; i < 3; i++)
            {
                int y = random.Next(image.Height);
                grap.DrawLine(pen,0,y,image.Width,y);
            }
            //在画板上画随机码内容
            grap.DrawString(content,font,brush,1,1);

            //增加随机噪点
            Random randomPoints = new Random((int)DateTime.Now.Ticks);
            Random randomXY = new Random(unchecked((int)DateTime.Now.Ticks));
            for (int i = 0; i < 10; i++)
            {
                int x = random.Next(image.Width);
                int y = random.Next(image.Height);

                grap.DrawLine(new Pen(Color.FromArgb(randomPoints.Next(0, 255), randomPoints.Next(0, 255), randomPoints.Next(0, 255)), 1), x, y, x + randomXY.Next(0, 10), y + randomXY.Next(0, 10));
            }

            for (int i = 0; i < 100; i++)
            {
                int x = random.Next(image.Width);
                int y = random.Next(image.Height);

                grap.DrawLine(new Pen(Color.FromArgb(randomPoints.Next(0, 255), randomPoints.Next(0, 255), randomPoints.Next(0, 255)), 0), x, y, x + randomXY.Next(0, 3), y + randomXY.Next(0, 3));
            }

            //以流的形式返回图片
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            image.Save(ms,System.Drawing.Imaging.ImageFormat.Jpeg);
            Response.ClearContent();
            Response.ContentType ="image/Jpeg";
            Response.BinaryWrite(ms.ToArray());
            grap.Dispose();

image.Dispose();

}

转载于:https://www.cnblogs.com/jhxgtl/archive/2009/02/03/1383165.html