public async Task <ApiError> BuyFromOfferAsync(int buyerid, long quantity, OfferModel offer, bool oldestfirst) { var checkresult = await ValidateModelAsync(offer, true); if (!checkresult.Successful) { return(checkresult); } if (buyerid <= 0) { return(new(string.Format(Strings.Invalid, "buyer id"))); } if (quantity == 0) { return(new(string.Format(Strings.Invalid, "quantity"))); } OfferEntity entity = offer !; try { return(ApiError.FromDalResult(await _offerRepository.BuyFromOfferAsync(buyerid, quantity, entity, oldestfirst))); } catch (Exception ex) { return(ApiError.FromException(ex)); } }