asp.net mvc 文件压缩下载

    public class ZIPCompressUtil
    {
        public static Tuple<bool, Stream> Zip(string strZipTopDirectoryPath, int intZipLevel, string strPassword, string[] filesOrDirectoriesPaths)
        {
            try
            {
                List<string> AllFilesPath = new List<string>();
                if (filesOrDirectoriesPaths.Length > 0) // get all files path
                {
                    for (int i = 0; i < filesOrDirectoriesPaths.Length; i++)
                    {
                        if (File.Exists(filesOrDirectoriesPaths[i]))
                        {
                            AllFilesPath.Add(filesOrDirectoriesPaths[i]);
                        }
                        else if (Directory.Exists(filesOrDirectoriesPaths[i]))
                        {
                            GetDirectoryFiles(filesOrDirectoriesPaths[i], AllFilesPath);
                        }
                    }
                }

                if (AllFilesPath.Count > 0)
                {
                    MemoryStream ms = new MemoryStream();
                    ZipOutputStream zipOutputStream = new ZipOutputStream(ms);
                    zipOutputStream.SetLevel(intZipLevel);
                    zipOutputStream.Password = strPassword;

                    for (int i = 0; i < AllFilesPath.Count; i++)
                    {
                        string strFile = AllFilesPath[i];
                        try
                        {
                            if (Directory.Exists(strFile)) //folder
                            {
                                string strFileName = strFile.Replace(strZipTopDirectoryPath, "");
                                if (strFileName.StartsWith(""))
                                {
                                    strFileName = strFileName.Substring(0);
                                }
                                ZipEntry entry = new ZipEntry(strFileName + "/");
                                entry.DateTime = DateTime.Now;
                                zipOutputStream.PutNextEntry(entry);
                            }
                            else //file
                            {
                                FileStream fs = File.OpenRead(strFile);

                                byte[] buffer = new byte[fs.Length];
                                fs.Read(buffer, 0, buffer.Length);

                                string strFileName = strFile.Replace(strZipTopDirectoryPath, "");
                                if (strFileName.StartsWith(""))
                                {
                                    strFileName = strFileName.Substring(0);
                                }
                                ZipEntry entry = new ZipEntry(strFileName);
                                entry.DateTime = DateTime.Now;
                                zipOutputStream.PutNextEntry(entry);
                                zipOutputStream.Write(buffer, 0, buffer.Length);

                                fs.Close();
                                fs.Dispose();
                            }
                        }
                        catch
                        {
                            continue;
                        }
                    }

                    zipOutputStream.Finish();
                    return new Tuple<bool, Stream>(true, ms);
                }
                else
                {
                    return new Tuple<bool, Stream>(false, null);
                }
            }
            catch
            {
                return new Tuple<bool, Stream>(false, null);
            }
        }

        private static void GetDirectoryFiles(string strParentDirectoryPath, List<string> AllFilesPath)
        {
            string[] files = Directory.GetFiles(strParentDirectoryPath);
            for (int i = 0; i < files.Length; i++)
            {
                AllFilesPath.Add(files[i]);
            }
            string[] directorys = Directory.GetDirectories(strParentDirectoryPath);
            for (int i = 0; i < directorys.Length; i++)
            {
                GetDirectoryFiles(directorys[i], AllFilesPath);
            }
            if (files.Length == 0 && directorys.Length == 0) //empty folder
            {
                AllFilesPath.Add(strParentDirectoryPath);
            }
        }
    }

        public ActionResult Export()
        {
            List<long> productIds = null;
            var url = Request.RawUrl;
            if (url.Contains("?"))
            {
                string paramStr = url.Substring(url.LastIndexOf("?"));
                string[] paramArray = paramStr.Split(‘&‘);
                productIds = paramArray
                    .Select(item => item.Split(‘=‘).Length > 1 ? item.Split(‘=‘)[1] : "0")
                    .Select(value => value.TryLong(0)).ToList();
            }

            if (Directory.Exists(Server.MapPath("~/上架商品")))
            {
                Directory.Delete(Server.MapPath("~/上架商品"), true);
            }

            var productlist = ProductOnSaleService.Instance.GetProductSkuImgsExportList(productIds);
            foreach (var productItem in productlist)
            {
                var dir = Server.MapPath("~/上架商品/") + productItem.ProductId + "-" + productItem.LongName;
                if (!Directory.Exists(dir))
                {
                    Directory.CreateDirectory(dir);
                }
                foreach (var skuItem in productItem.Skus)
                { 
                    Bitmap rqBtimap = QrCodeHelper.Encode(BizKeyValService.Instance.Get(EnumBizKey.ProductShareUrl).BizVal
                        + "?id=" + productItem.ProductId + "&skuid=" + skuItem.SkuId, 430, 430);
                    rqBtimap.Save(dir + "/" + productItem.ProductId + "-" + skuItem.SkuId + "-" + skuItem.SkuName + ".jpg");
                    
                }
            }

            var strZipTopDirectoryPath = Server.MapPath("~/");
            const int intZipLevel = 6;
            const string strPassword = "";
            var filesOrDirectoriesPaths = new string[] { Server.MapPath("~/上架商品") };
            var result = ZIPCompressUtil.Zip(strZipTopDirectoryPath, intZipLevel, strPassword, filesOrDirectoriesPaths);
            var buffer = new byte[result.Item2.Length];
            result.Item2.Position = 0;
            result.Item2.Read(buffer, 0, buffer.Length);
            result.Item2.Close();
            Response.AppendHeader("content-disposition", "attachment;filename=上架商品.zip");
            Response.BinaryWrite(buffer);
            Response.Flush();
            Response.End();
            return new EmptyResult();
        }

$("#btnExpress").click(function () {
        var selectedList = $.getSelectId(true);
        if (selectedList.length == 0) {
            $.alert("请选择商品");
            return;
        }
        var url = "/Product/ProductOnSale/Export";
        for (var i = 0; i < selectedList.length; i++) {
            url = (i == 0 ? url + "?param" + i + "=" + selectedList[i].toString() 
                : url + "&param" + i + "=" + selectedList[i].toString());
        }
        location.href = url;
    });