public void Login()
        {
            TimetableEvents.Clear();
            ClearEventArrays();

            if (Username == "Gergely")
            {
                //logins automatically
                Cs.UserLogin(Username, "pw123");
                isLoggedIn = true;

                ObservableCollection <Event> temp = new ObservableCollection <Event>(Cs.ListEvents(Username));
                foreach (Event e in temp)
                {
                    TimetableEvents.Add(e);
                }
                SortEvents();
            }
            else if (Username == "Adrian")
            {
                //logins automatically
                Cs.UserLogin(Username, "pw789");
                isLoggedIn = true;

                ObservableCollection <Event> temp = new ObservableCollection <Event>(Cs.ListEvents(Username));
                foreach (Event e in temp)
                {
                    TimetableEvents.Add(e);
                }
                SortEvents();
            }
            else
            {
                Alert("Invalid username!");
                isLoggedIn = false;
            }

            DeleteCommand.Update();
            AddCommand.Update();
        }