一、zip打包下载

1.依赖引用：ICSharpCode.SharpZipLib

2.设定网站有单独文件服务器，网站目录下有虚拟路径FileFolder，通过虚拟路径将文件映射到文件服务器。

设定根据Guid id可以获取到所需的文件集合

/// 
        /// 下载zip文件        /// 
        ///         public void DownloadFiles(Guid id)        {            var files = fileservice.GetFiles(c => c.GroupId == id).ToList();            List
     
       paths = new List
      
       (files.Count);            //数据库文件存储示例：\FileFolder\file/20161215170146_9767.pdf            string savePath = HttpContext.Server.MapPath(@"~\FileFolder\");            foreach (var file in files)            {                //验证文件是否存在...                paths.Add(savePath + file.FilePath.Replace(@"\FileFolder\", ""));            }            string downloadName = "批量下载" + files[0].FileName + "等";            HttpContext.Response.Clear();            HttpContext.Response.AddHeader("content-disposition", "attachment; filename=" + downloadName + ".zip");            HttpContext.Response.ContentType = "application/zip";            HttpContext.Response.CacheControl = "Private";            HttpContext.Response.Cache.SetExpires(DateTime.Now.AddMinutes(3));                        DownloadZipToBrowser(paths);        }
      
     

/// 
        /// 下载压缩文件        /// 
        ///         private void DownloadZipToBrowser(IEnumerable
     
       list)        {            ZipOutputStream zipOutputStream = null;            var response = HttpContext.Response;            try            {                byte[] buffer = new byte[4096];                zipOutputStream = new ZipOutputStream(response.OutputStream);                zipOutputStream.SetLevel(6); //0-9, 9 being the highest level of compression                foreach (string fileName in list)                {                    string filepath = Server.MapPath(fileName);                    Stream fs = System.IO.File.OpenRead(filepath);                    ZipEntry entry = new ZipEntry(Path.GetFileName(filepath));                    entry.Size = fs.Length;                    zipOutputStream.PutNextEntry(entry);                    int count = fs.Read(buffer, 0, buffer.Length);                    while (count > 0)                    {                        zipOutputStream.Write(buffer, 0, count);                        count = fs.Read(buffer, 0, buffer.Length);                        if (!response.IsClientConnected)                        {                            break;                        }                        response.Flush();                    }                    fs.Close();                }            }            catch (Exception)            {            }            finally            {                if (zipOutputStream != null)                    zipOutputStream.Close();                response.Flush();                response.End();            }        }
     

二、直接下载某一个文件：

/// 
        /// 下载文件        /// 
        /// FileId        public void DownloadFile(int id )        {            string savePath = HttpContext.Server.MapPath(@"~\FileFolder\");            var fileinfo = fileservice.Find(id);            string fullname = savePath + fileinfo.FilePath.Replace(@"\FileFolder\", "");            //string fullname = fileinfo.FilePath;            //判断文件是否存在            if (!System.IO.File.Exists(fullname))            {                Response.Write("该文件不存在服务器上");                Response.End();                return;            }            FileInfo fi = new FileInfo(fullname);            //**********处理可以解决文件类型问题            string fileextname = fi.Extension;            string DEFAULT_CONTENT_TYPE = "application/unknown";            RegistryKey regkey, fileextkey;            string filecontenttype;            try            {                regkey = Registry.ClassesRoot;                fileextkey = regkey.OpenSubKey(fileextname);                filecontenttype = fileextkey.GetValue("Content Type", DEFAULT_CONTENT_TYPE).ToString();            }            catch            {                filecontenttype = DEFAULT_CONTENT_TYPE;            }            //**********end            Response.Clear();            Response.Charset = "utf-8";            Response.ContentEncoding = System.Text.Encoding.UTF8;            Response.AppendHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(fileinfo.FileName, System.Text.Encoding.UTF8));            Response.ContentType = filecontenttype;            Response.WriteFile(fullname);            Response.End();        }