public void UploadFile2() { //获取文件值 string filename = Request.QueryString["value"]; //获取图片 string oldfilename = "wechat.png"; var contentType = MimeMapping.GetMimeMapping(oldfilename); var bytes = mongoDBHelper.DownloadAsBytesByName(oldfilename); //通过Metadata 添加附加信息 GridFSUploadOptions option = new GridFSUploadOptions(); option.ContentType = contentType; mongoDBHelper.UploadFromBytes(bytes, filename, option); ViewImg(); }