public Entities.Product Save(int? id, string productCode, int? productGroupId, int? customerId,
            int? supplierId, string name, string description, decimal? weight, string image,
            decimal? outerDiameter, decimal? innerDiameter, decimal? height, decimal? width,
            decimal? length, DateTime? dateCreated, DateTime? dateModified, string createdBy,
            string modifiedBy, string remarks)
        {
            _da = new ProductDataAccess();
            if (id.HasValue)
                return _da.Update(id.Value, productCode, productGroupId, customerId, supplierId, name,
                          description, weight, image, outerDiameter, innerDiameter, height, width,
                          length, dateCreated, dateModified, createdBy, modifiedBy, remarks);

            return _da.Insert(productCode, productGroupId, customerId, supplierId, name,
                        description, weight, image, outerDiameter, innerDiameter, height, width,
                        length, DateTime.Now, dateModified, createdBy, modifiedBy, remarks);
        }