public List <Currency> GetCurrencyDataByProvider_itemList(List <Provider_item> provider_itemList) { List <Currency> result = new List <Currency>(); foreach (Provider_item provider_item in provider_itemList) { var currencyFoundList = _dataSet.GetCurrencyDataByProvider_item(provider_item); if (currencyFoundList.Count() > 0) { result.Add(currencyFoundList.First()); } } return(result); }