public static void UpdateOrder(this Order entity, OrderModel viewModel)
        {
            entity.CustomerNumber = viewModel.CustomerNumber;
            entity.OrderDate = viewModel.OrderDate;
            entity.DeliveryDate = viewModel.DeliveryDate;

            if (viewModel.OrderPositions != null)
            {
                if (entity.OrderPositions == null)
                    entity.OrderPositions = new List<OrderPosition>();

                foreach (OrderPositionModel pos in viewModel.OrderPositions)
                {
                    var posEntity = entity.OrderPositions.SingleOrDefault(x => x.ID == pos.PositionOrderId);
                    if (posEntity == null || posEntity.ID == 0)
                    {
                        posEntity = new OrderPosition();
                        posEntity.UpdateOrderPosition(pos);
                        entity.OrderPositions.Add(posEntity);
                    }
                    else
                    {
                        posEntity.UpdateOrderPosition(pos);
                    }
                }
            }

            entity.TotalPrice = entity.OrderPositions.Sum(x => x.Total);
        }
        public int AddOrder(OrderModel orderModel)
        {
            if (orderModel.OrderPositions.Count < 1)
                return -1;

            var order = new Order
            {
                CustomerNumber = orderModel.CustomerNumber.Trim(),
                TotalPrice = orderModel.TotalPrice,
                DeliveryDate = orderModel.DeliveryDate,
                OrderDate = DateTime.Now
            };

            foreach (var position in orderModel.OrderPositions)
            {
                var positionOrder = new OrderPosition
                {
                    OrderID = order.ID,
                    Pieces = position.Pieces != null ? position.Pieces.Trim() : null,
                    PositionNumber = position.PositionNumber,
                    Price = position.Price,
                    Text = position.Text != null ? position.Text.Trim() : null,
                    Total = position.Total
                };
                order.TotalPrice += positionOrder.Total;
                order.OrderPositions.Add(positionOrder);
            }

            try
            {
                _orderBusinessService.AddOrder(order);
            }
            catch (Exception ex)
            {
                //TODO:
                throw;
            }
            return order.ID;
        }