private void ReloadChildrens(int categoria_id)
 {
     if (this.is_folder)
     {
         List <media_files>   mflist = DBManager.MediaFilesRepo.FindByCategoria(categoria_id, this.id, false);
         MediaFile_Basic_Info child;
         foreach (media_files mf in mflist)
         {
             child = new MediaFile_Basic_Info();
             child.ReadMediaFile(mf);
             this.Childrens.Add(child);
         }
     }
 }
        private long calculate_size(MediaFile_Basic_Info mfbi)
        {
            long size = 0;

            if (mfbi.is_folder)
            {
                foreach (MediaFile_Basic_Info item in mfbi.Childrens)
                {
                    if (mfbi.is_folder)
                    {
                        size += calculate_size(item);
                    }
                }
            }
            else
            {
                FileInfo fi = new FileInfo(mfbi.file_url);
                size += fi.Length;
            }

            return(size);
        }