递归操作文件

        /// <summary>
        /// 找出全部的子文件夹
        /// </summary>
        /// <param name="rootPath">根目录</param>
        /// <returns></returns>
        public static List<DirectoryInfo> GetAllDirectory(string rootPath)
        {
            if (!Directory.Exists(rootPath))
                return new List<DirectoryInfo>();

            List<DirectoryInfo> directoryList = new List<DirectoryInfo>();//容器
            DirectoryInfo directory = new DirectoryInfo(rootPath);//root文件夹
            directoryList.Add(directory);

            return GetChild(directoryList, directory);            
        }

        /// <summary>
        /// 完成 文件夹--子目录--放入集合
        /// </summary>
        /// <param name="directoryList"></param>
        /// <param name="directoryCurrent"></param>
        /// <returns></returns>
        private static List<DirectoryInfo> GetChild(List<DirectoryInfo> directoryList, DirectoryInfo directoryCurrent)
        {
            var childArray = directoryCurrent.GetDirectories();
            if (childArray != null && childArray.Length > 0)
            {
                directoryList.AddRange(childArray);
                foreach (var child in childArray)
                {
                    GetChild(directoryList, child);
                }
            }
            return directoryList;
        }