public List <File> GetFiles(Folder folder)
        {
            string sql  = "SELECT * FROM files WHERE folder_id =" + folder.FolderId + " ";
            var    file = m_manager.ExecuteSelectQuery(sql);

            List <File> files = new List <File>();

            for (int i = 0; i < file.Rows.Count; i++)
            {
                File currentfile = new File(file.Rows[i].ItemArray);
                files.Add(currentfile);
            }
            return(files);
        }