private void UpdateMails() { LastUpdate = DateTime.Now; var lastDate = _proc.LastMailDate(_fsMails); FSharpList <Common.EMail> newMails; try { newMails = MailReader.downloadMailsAfterDate(lastDate); } catch (Exception ex) { Debug.WriteLine("{0} - Exception: {1}", DateTime.Now, ex.Message); return; } var updatedCollection = MailReader.updateAndWriteAfterLastDate(_fsMails, lastDate); LastUpdate = DateTime.Now; Debug.WriteLine("{0} - New items: {1}", LastUpdate, updatedCollection.Length - _fsMails.Length); _fsMails = updatedCollection; _mails = _fsMails.ToList(); }