生成并保存二维码

public class QRcode
    {
        //检测是否存在二维码(不存在则生成)
        public static void CheckCode(string nr, string url, string fileName)
        {
            try
            {
                var uploadFolder = HttpContext.Current.Server.MapPath(url);
                string filepath = uploadFolder + fileName;
                FileInfo fi = new FileInfo(filepath);
                if (!fi.Exists)
                {
                    QRCodeEncoder qrCodeEncoder = new QRCodeEncoder();
                    qrCodeEncoder.QRCodeEncodeMode = QRCodeEncoder.ENCODE_MODE.BYTE;
                    qrCodeEncoder.QRCodeScale = 4;
                    qrCodeEncoder.QRCodeVersion = 7;
                    qrCodeEncoder.QRCodeErrorCorrect = QRCodeEncoder.ERROR_CORRECTION.M;
                    System.Drawing.Image image = qrCodeEncoder.Encode(nr);
                    image = new Bitmap(image, 1280, 1280);
                    if (!Directory.Exists(uploadFolder))
                    {
                        Directory.CreateDirectory(uploadFolder);
                    }
                    System.IO.FileStream fs = new System.IO.FileStream(filepath, System.IO.FileMode.OpenOrCreate, System.IO.FileAccess.Write);
                    image.Save(fs, System.Drawing.Imaging.ImageFormat.Jpeg);

                    fs.Close();
                    image.Dispose();
                }
            }
            catch
            {
                return;
            }
        }
    }