public async Task AddProduct(ProductModel product) { if (product.ContainsNullStrings()) { throw new InvalidOperationException(ServiceErrorsConstants.RequiredFields); } if (!_categoriesRepository.All().Any(c => c.Id == product.CategoryId)) { throw new InvalidOperationException(string.Format(ServiceErrorsConstants.CategoryDoesNotExist, product.CategoryId)); } var dbEntity = new Product { CategoryId = product.CategoryId, Manufacturer = product.Manufacturer, Model = product.Model, Title = product.Title, Description = product.Description, Quantity = product.Quantity, Price = product.Price, Discount = product.Discount, PurchaseId = 1, }; _productRepository.Add(dbEntity); await _productRepository.SaveChangesAsync(); var ent = _productRepository.All().ToList(); }