Nhibernate Throws Found shared references to a collection - nhibernate

Question

I have read thru a number of other questions similar to this one - but being new to Nhibernate, none of them seem to answer my question of why is Inhibernate throwing a "Found shared references to a collection: Order.ShippingAddress.Items" to the following code:
VendorOrderNotificationAcknowledgement ICheckoutVendorService.SendOrderNotification(VendorOrderNotification request)
{
OrderRepository repo = new OrderRepository();
var order =(AbstractOrder) repo.FindByCartId(request.OrderNotification.CartOrderId);
ShippingAddress billingAddress = order.ShippingAddresses[0];
var itemsFromDb = billingAddress.Items;
order.ClearAllShippingAddresses();
wcfFactory.UpdateOrder(order); //NO ERROR THROWN HERE!
ShippingAddress shippingAddress = orderHelper.CreateShippingAddress(request.ShippingDetails);
shippingAddress.Items = itemsFromDb;
order.AddShippingAddress(shippingAddress);
order.SourceCode = _sourceCode;
order.TaxAmount = 0;
order.GiftCertificateAmount = 0;
order.Status = StatusCode.Approved;
order.CreatedAt = request.OrderNotification.OrderTime.Year >2010
? request.OrderNotification.OrderTime
: DateTime.Now;
order.PurchasedDate=
request.OrderNotification.OrderTime.Year>2010
? request.OrderNotification.OrderTime
: DateTime.Now;
order.UpdatedAt = DateTime.Now;
if (request.OrderNotification.OrderCharges != null)
{
order.ShippingAmount = request.OrderNotification.OrderCharges.Shipping;
order.TaxAmount = request.OrderNotification.OrderCharges.DutyAndTaxes;
}
else
{
order.ShippingAmount = 0;
order.TaxAmount = 0;
}
order.UseGiftWrap = false;
order.SourceCode = _sourceCode;
UpdateEshopWorldOrder(order); // THROWS FOUND SHARED REFERENCES TO A COLLECTION: ORDER.SHIPPINGADDRESS.ITEMS
var orderDto = orderHelper.CreateOrderDto(billingAddress, orderHelper, order);
var dtoShippingAddresses = orderHelper.CreateDtoShippingAddresses(order);
orderDto.ShippingAddresses = dtoShippingAddresses;
ShippingMethodDto shippingMethodDto = 0;
var mine = wcfFactory.SendOrder(orderDto);
//More Code below here ...
}
public OrderDto CreateOrderDto(ShippingAddress billingAddress, OrderHelper orderHelper, AbstractOrder order)
{
OrderDto orderDto = new OrderDto();
orderDto.AlternateOrderId = order.Id.ToString();
orderDto.ConfirmationNumber = order.ConfirmationNumber;
orderDto.Coupons = new string[0];
orderDto.DiscountAmount = order.DiscountAmount;
orderDto.GiftCardAmount = order.GiftCertificateAmount;
orderDto.PurchaseDate = order.PurchasedDate;
orderDto.ShippingAmount = order.ShippingAmount;
orderDto.SourceCode = order.SourceCode;
orderDto.TaxAmount = order.TaxAmount;
orderDto.UseGiftWrap = order.UseGiftWrap;
var customerDto = orderHelper.CreateCustomerDto(billingAddress);
orderDto.SoldTo = customerDto;
return orderDto;
}
public void UpdateEshopWorldOrder(AbstractOrder order)
{
try
{
//Session.Update(order);
// transaction.Commit();
Session.Flush();
}
catch (Exception ex)
{
_logger.Debug("order saved failed with an error of " + ex.Message);
_logger.Error(ex);
throw;
}
}
Any insights are appreciated....
thnx

Answer 1

I think the problem is, that your itemsFromDB collection object is referenced by shippingAddress and also by billingAddress.
Both entities need their own collection-objects. Both collections however may contain references to the same address-objects.
So I assume replacing shippingAddress.Items = itemsFromDb; with something like
shippingAddress.Items.AddRange(itemsFromDb)
or
shippingAddress.Items = new List<ShippingAddress>(itemsFromDb) should do the trick