private async void LoadExchangeRateList() { if (isExchangeRateListLoaded) { return; } if (queryDispatcher == null) { return; } List <ExchangeRateModel> exchangeRates = await queryDispatcher.QueryAsync(new ListTargetCurrencyExchangeRates(UniqueCode)); if (exchangeRates == null) { return; } ExchangeRates.AddRange(exchangeRates); ExchangeRates.SortDescending(e => e.ValidFrom); RaisePropertyChanged(nameof(ExchangeRates)); isExchangeRateListLoaded = true; }