internal List <TDto> RetrieveOpportunitysByCustomer <TDto>(object customerId, IDataConverter <OpportunityData, TDto> converter) where TDto : class { ArgumentValidator.IsNotNull("customerId", customerId); ArgumentValidator.IsNotNull("converter", converter); IOpportunityService service = UnitOfWork.GetService <IOpportunityService>(); var query = service.SearchByCustomer(customerId); if (query.HasResult) { return(query.DataToDtoList(converter).ToList()); } return(null); }