高校手机签到系统——zxing.net生成二维码（补充）

　　高校手机签到系统——第一部分Authority权限系统（上）

　　高校手机签到系统——第一部分Authority权限系统（下）

　　高校手机签到系统——手机客户端

　　关于zxing.net的使用网上已有很多说明，可是在mvc模式下，怎么保存生成的图片返回链接？

使用zxing生成bitmap:

BarcodeWriter writer = new BarcodeWriter
            {
                Format = BarcodeFormat.QR_CODE,
                Options = new EncodingOptions
                    {
                        Width = 400,
                        Height = 400
                    }
            };
            string time = DateTime.Now.ToString();
            Bitmap bitmap = writer.Write(id + "|" + time);

 此bitmap有一save方法Image.Save (String, ImageCodecInfo, EncoderParameters)，参数分别是路径，编码器，以及编码器参数。

初始化编码器ImageCodecInfo imageCodecInfo = (from e in ImageCodecInfo.GetImageEncoders() where e.MimeType == "image/jpeg" select e).First();

初始化编码器参数EncoderParameters encoderParameters = new EncoderParameters(1);
            EncoderParameter encoderParameter = new EncoderParameter(Encoder.Quality, 75L);

接下来保存到相应的路径即可。完整的代码：

public ActionResult LoadQrcode(string id)
        {
            BarcodeWriter writer = new BarcodeWriter
            {
                Format = BarcodeFormat.QR_CODE,
                Options = new EncodingOptions
                    {
                        Width = 400,
                        Height = 400
                    }
            };
            string time = DateTime.Now.ToString();
            Bitmap bitmap = writer.Write(id + "|" + time);
            ImageCodecInfo imageCodecInfo = (from e in ImageCodecInfo.GetImageEncoders() where e.MimeType == "image/jpeg" select e).First();
            EncoderParameters encoderParameters = new EncoderParameters(1);
            EncoderParameter encoderParameter = new EncoderParameter(Encoder.Quality, 75L);
            encoderParameters.Param[0] = encoderParameter;
            if (Directory.Exists(Server.MapPath("/Images/" + id + "/")))
            {
                FileInfo[] files = new DirectoryInfo(Server.MapPath("/Images/" + id + "/")).GetFiles();
                foreach (FileInfo fi in files)
                    System.IO.File.Delete(Path.Combine(Server.MapPath("/Images/" + id + "/"), fi.Name));
            }
            else
                Directory.CreateDirectory(Server.MapPath("/Images/" + id + "/"));
            bitmap.Save(Path.Combine(Server.MapPath("/Images/" + id + "/"), DateTime.Now.Date.ToFileTimeUtc()+ ".jpeg"), imageCodecInfo, encoderParameters);
            return Json("/Images/" + id + "/" + DateTime.Now.Date.ToFileTimeUtc() + ".jpeg", JsonRequestBehavior.AllowGet);
        }