Merge Changes must ignore deleted items if not persisted

[noufionline]

Hi Tony,

I am facing an issue with the change tracker.

If a user adds a record and then changes his mind and deletes it, ChangeTracker should not keep a reference to this item in the tracker.

Please see the code snippet extracted from your demo.

var createdOrder = CreateOrder(client, newOrder, formatter);
            PrintOrderWithDetails(createdOrder);

            // Update the order
            Console.WriteLine("\nPress Enter to update order details");
            Console.ReadLine();

            // Start change-tracking the order
            var changeTracker = new ChangeTrackingCollection<Order>(createdOrder);

            // Modify order details
            createdOrder.OrderDetails[0].UnitPrice++;
            createdOrder.OrderDetails.RemoveAt(1);
            var newItem = new OrderDetail
            {
                OrderId = createdOrder.OrderId,
                ProductId = 3,
                Quantity = 15,
                UnitPrice = 30
            };
            createdOrder.OrderDetails.Add(newItem);
           //Problem occures after this deletion which is not persisted yet in the database.
            createdOrder.OrderDetails.Remove(newItem);
            
           // At this point neither change tracker deleted collection nor the orderDetails collection has the deleted item.
            // Submit changes
            var changedOrder = changeTracker.GetChanges().SingleOrDefault();
           // Once the GetChanges called OrderDetails is again populated with Deleted Item
            var updatedOrder = UpdateOrder(client, changedOrder, formatter);

            // Merge changes
            changeTracker.MergeChanges(updatedOrder);

           // After merge changes only 2 records must be available but its shows 3. The deleted item which is not persisted in the database is still shown

            Console.WriteLine("Updated order:");
            PrintOrderWithDetails(createdOrder);

[noufionline]

Please find some time to fix this.

[cbgreely]

Hi Tony,

I am hitting this issue also. In debugging the code, it appears that ChangeTrackingCollection.RemoveItem is adding the item to the _deletedEntities collection even though it was newly added. Does the TrackingState need to be set to deleted AFTER deciding whether or not to add it to _deletedEntities? See my code snippet below. Thanks

        protected override void RemoveItem(int index)
        {
            // Mark existing item as deleted, stop listening for property changes,
            // then fire EntityChanged event, and cache item.
            if (Tracking)
            {
                // Get item by index
                TEntity item = Items[index];

                // Exclude this collection and Parent entity (used in M-M relationships)
                // from recusive algorithms: SetModifiedProperties, SetTracking and SetState.
                var visitationHelper = new ObjectVisitationHelper(Parent);
                visitationHelper.TryVisit(this);

                // Remove modified properties
                item.ModifiedProperties = null;
                item.SetModifiedProperties(null, visitationHelper.Clone());

                // Stop listening for property changes
                item.PropertyChanged -= OnPropertyChanged;

                // Disable tracking on trackable properties
                item.SetTracking(false, visitationHelper.Clone(), true);

                // Mark item and trackable collection properties
                item.SetState(TrackingState.Deleted, visitationHelper.Clone());

                // Fire EntityChanged event
                if (EntityChanged != null) EntityChanged(this, EventArgs.Empty);

                //SHOULD THE FOLLOWING STATEMENT GO ABOVE "item.SetState(TrackingState.Deleted, visitationHelper.Clone());" ??
                // Cache deleted item if not added or already cached
                if (item.TrackingState != TrackingState.Added
                    && !_deletedEntities.Contains(item))
                    _deletedEntities.Add(item);
            }
            base.RemoveItem(index);
        }