public void DownloadItemsCompleted(object sender,
                                           DownloadCompletedEventArgs e)
        {
            try
            {
                ItemCache.SetCurrentSchedule(e.schedule);

                // success
                Debug.WriteLine("++++!!! items downloaded: " + e.schedule.Items.Aggregate("", (s, i) => s + i.Number + ", "));

                // update fields (and GUI)
                UpdateItemFields();
            }
            catch (Exception ex)
            {
                // failure
                Debug.WriteLine("Item download did not succeed. There may have been a problem with the data received");
            }
        }