public override IList <MediaItem> GetMediaItems(string parentId)
        {
            var mediaItems = new List <MediaItem>();

            EnsureAzureConnection();
            if (parentId == "-1")
            {
                List <string> containers = _factory.GetAllContainers();
                mediaItems.AddRange(containers.Select(container => container.ContainerToMediaItem()));
            }
            else
            {
                List <string> items = _factory.GetBlobsForContainer(parentId);
                mediaItems.AddRange(items.Select(item => GetMediaItemWithUrl(_config.CdnDomain, item)));
            }

            return(mediaItems);
        }