操作文件夹，删除所有空文件夹

public static void RemoveAllEmptyDirectories(string physicalPath)
        {
            foreach (var directory in Directory.GetDirectories(physicalPath))
            {
                RemoveAllEmptyDirectories(directory);

                if (Directory.GetFiles(directory).Length == 0 && Directory.GetDirectories(directory).Length == 0)
                {
                    Directory.Delete(directory, false);
                }
            }
        }