/// <summary>
        ///   用来遍历删除目录下的文件以及该文件夹
        /// </summary>
        public void DeleteFileByDirectory(DirectoryInfo info)
        {
            foreach (DirectoryInfo newInfo in info.GetDirectories())
            {
                DeleteFileByDirectory(newInfo);
            }
            foreach (FileInfo newInfo in info.GetFiles())
            {
                newInfo.Attributes = newInfo.Attributes &~(FileAttributes.Archive | FileAttributes.ReadOnly | FileAttributes.Hidden);
                newInfo.Delete();
            }
            info.Attributes = info.Attributes & ~(FileAttributes.Archive | FileAttributes.ReadOnly | FileAttributes.Hidden);
            info.Delete();

        }