WEB Service产生随机验证码图片

WEB服务端方法：

[WebMethod]
        public byte[] GenerateVerifyImage(int nLen, ref string strKey)
        {
            int nBmpWidth = 13 * nLen + 5;
            int nBmpHeight = 25;
            System.Drawing.Bitmap bmp = new System.Drawing.Bitmap(nBmpWidth, nBmpHeight);

            int nRed, nGreen, nBlue;  // 背景的三元色
            System.Random rd = new Random((int)System.DateTime.Now.Ticks);
            nRed = rd.Next(255) % 128 + 128;
            nGreen = rd.Next(255) % 128 + 128;
            nBlue = rd.Next(255) % 128 + 128;
            System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(bmp);
            graph.FillRectangle(new SolidBrush(System.Drawing.Color.FromArgb(nRed, nGreen, nBlue))
             , 0
             , 0
             , nBmpWidth
             , nBmpHeight);
            int nLines = 3;
            System.Drawing.Pen pen = new System.Drawing.Pen(System.Drawing.Color.FromArgb(nRed - 17, nGreen - 17, nBlue - 17), 2);
            for (int a = 0; a < nLines; a++)
            {
                int x1 = rd.Next() % nBmpWidth;
                int y1 = rd.Next() % nBmpHeight;
                int x2 = rd.Next() % nBmpWidth;
                int y2 = rd.Next() % nBmpHeight;
                graph.DrawLine(pen, x1, y1, x2, y2);
            }
            string strCode = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
            string strResult = "";
            for (int i = 0; i < nLen; i++)
            {
                int x = (i * 13 + rd.Next(3));
                int y = rd.Next(4) + 1;
                System.Drawing.Font font = new System.Drawing.Font("Courier New",
                 12 + rd.Next() % 4,
                 System.Drawing.FontStyle.Bold);
                char c = strCode[rd.Next(strCode.Length)];  // 随机获取字符
                strResult += c.ToString();
                graph.DrawString(c.ToString(),
                 font,
                 new SolidBrush(System.Drawing.Color.FromArgb(nRed - 60 + y * 3, nGreen - 60 + y * 3, nBlue - 40 + y * 3)),
                 x,
                 y);
            }
            System.IO.MemoryStream bstream = new System.IO.MemoryStream();
            bmp.Save(bstream, System.Drawing.Imaging.ImageFormat.Jpeg);
            bmp.Dispose();
            graph.Dispose();

            strKey = strResult;
            byte[] byteReturn = bstream.ToArray();
            bstream.Close();

            return byteReturn;
        }

客户端应用：

string code1 = GenerateCheckCode();//产生随机字符串方法如下：
            ValidateCodeService.ValidateCodeWebServiceSoapClient vws = new ValidateCodeService.ValidateCodeWebServiceSoapClient();
            byte[] data = vws.enValidateByte(code1);
            MemoryStream ms = new MemoryStream(data);
            Image img = Image.FromStream(ms);//将字符流转化为图片，用于显示在picturebox控件中;
            pictureBox2.Image = img;

private string GenerateCheckCode() 
        { 
            int number;
            char code; 
            string checkCode = String.Empty; 
            Random random = new Random(); 
            for (int i = 0; i < 4; i++) 
            { number = random.Next(); 
                if (number % 2 == 0)                
                    code = (char)('0' + (char)(number % 10));
                else                
                    code = (char)('A' + (char)(number % 26));
                checkCode += code.ToString(); 
            } 
             
            return checkCode; 
        }