public void RetrieveHistoryList()
        {
            HistoryItems = _dataStore.GetAllWeatherHistory();

            if (!HistoryItems.Count.Equals(0))
            {
                DisplayErrorMsg = false;

                var data = HistoryItems.Select(
                    x => new HistoryRowViewModel()
                {
                    HistoryDataItem = x,
                    Id              = x.Id,
                    City            = x.City,
                    TempDescription = x.TempDescription,
                    WeatherIcon     = x.WeatherIcon,
                    Temp            = x.Temp,
                    MinTemp         = x.MinTemp,
                    MaxTemp         = x.MaxTemp,
                    SearchDate      = x.SearchDate.ToString("g")
                });

                HistoryDataItem = new ObservableCollection <HistoryRowViewModel>(data);
            }
            else
            {
                HistoryDataItem = null;
                DisplayErrorMsg = true;
                ErrorMsg        = "You have no weather history.";
            }
        }