.net 生成html文件后压缩成zip文件并下载

这里只做一个简单的实例
 public ActionResult Index()
        {

            string path = Server.MapPath("/test/");//文件输出目录

            Encoding code = Encoding.GetEncoding("gb2312");

            StreamWriter sw = null;

            string str = "<html><body>$ShowArticle$</body></html>";//读取模版页面html代码

            string htmlfilename = DateTime.Now.ToString("yyyyMMddHHmmss") + ".html";//静态文件名

            // 替换内容

            str = str.Replace("$ShowArticle$", "你好");

            // 写文件
            try
            {
                sw = new StreamWriter(Path.Combine(path, htmlfilename), true, code);
                sw.Write(str);
                sw.Close();
                byte[] buffer = null;
                var ms = new MemoryStream();
                using (var file = ZipFile.Create(ms))
                {
                    file.BeginUpdate();
                    foreach (string item in Directory.GetFiles(Server.MapPath("/test")))
                    {
                        file.Add(Server.MapPath(Path.Combine( "test",Path.GetFileName(item))));
                    }

                    file.CommitUpdate();

                    buffer = new byte[ms.Length];
                    ms.Position = 0;
                    ms.Read(buffer, 0, buffer.Length);
                }

                //IE和其它浏览器都要进行UTF-8编码，中文不编码会出现乱码

                Response.AddHeader("content-disposition", "attachment;filename=" + HttpUtility.UrlEncode("test") + ".zip");
                Response.BinaryWrite(buffer);
                Response.Flush();
                Response.End();
            }
            catch (Exception ex)
            {
                return Content(ex.Message);
            }

            finally
            {
                sw.Close();
            }
            return View();
        }