在网上找了一个压缩文件夹的例子，需要要把压缩文件保存到流中，不知道为什么流转换成文件就一直打开失败

代码如下：

  class Class1
    {
        public static void Main(string[] args)
        {
            var zipFileDirectory = ZipFileDirectory("C:\\test\\test1");
      File.WriteAllBytes("C:\\test\\test1.zip", ZipFile.ToArray());
        }
        private static byte[] ZipFileDirectory(string strDirectory)
        {
            using (System.IO.MemoryStream ZipFile = new MemoryStream())
            {
                using (ZipOutputStream s = new ZipOutputStream(ZipFile))
                {
                    s.SetLevel(9);
                    ZipSetp(strDirectory, s, "");
                    var buffer = ZipFile.ToArray();
                    return buffer;
                }
            }
        }

        private static void ZipSetp(string strDirectory, ZipOutputStream s, string parentPath, List<string> files = null)
        {
            if (strDirectory[strDirectory.Length - 1] != Path.DirectorySeparatorChar)
            {
                strDirectory += Path.DirectorySeparatorChar;
            }

            string[] filenames = Directory.GetFileSystemEntries(strDirectory);


            foreach (string file in filenames)// 遍历所有的文件和目录
            {
                if (files != null && !files.Contains(file))
                {
                    continue;
                }
                if (Directory.Exists(file))// 先当作目录处理如果存在这个目录就递归Copy该目录下面的文件
                {
                    string pPath = parentPath;
                    pPath += Path.GetFileName(file);
                    pPath += "\\";
                    ZipSetp(file, s, pPath, files);
                }
                else // 否则直接压缩文件
                {
                    //打开压缩文件
                    string fileName = parentPath + Path.GetFileName(file);
                    ZipEntry entry = new ZipEntry(fileName) { DateTime = DateTime.Now };

                    s.PutNextEntry(entry);
                    using (FileStream fs = File.OpenRead(file))
                    {
                        int sourceBytes;
                        do
                        {
                            byte[] buffer = new byte[2048];
                            sourceBytes = fs.Read(buffer, 0, buffer.Length);
                            s.Write(buffer, 0, sourceBytes);
                        } while (sourceBytes > 0);

                    }
                }
            }
        }
    }