The entities model works great with WPF for data retrieval and presentation. I haven’t actually tried using it for transactional updates. If you have a simple sample that demonstrates the problem you describe, I wouldn’t mind having a look. Feel free to send it to my ask[at]drwpf[dot]com address.

Cheers,
-dw

Specifically the Collection View as I found examples all over, but no one explaining quite what it does or why it’s necessary. Though I cannot say I am entirely clear on the topic, I have a decent idea now.

Perhaps this is because my situation is a bit different, in that my data is coming from a LINQ to Entities models, and I am trying to use a DataGrid.

I have been able to use ItemsSource and tie it directly to an entity like my Customers EntityObject class (the mapped table basically) and it displays items correctly.

All adds, edits, and deletes appear on the DataGrid regardless of further coding.

At this point I am trying to resolve the issue with changes being persisted to the database back through the entities layer.

The commits are made after most of the events are fired, so I am not sure where to write the code that pushes the changes through the entity model.

I’ve tried using the RowEditEnding handler to some success (using an IEditableCollectionView for queueing Adds and Edits to be commited), but again the event finishes before the commit to the collection is actually performed… so if I call entities.SaveChanges() I get concurrency exceptions and other issues with the model not matching the collection.

Any help here? Again, I’ve found many examples, but none of them very helpful when using Entities model for CRUD.

Thank you.

Yes, that binding should work fine. The ObservableCollection does implement INotifyPropertyChanged and it raises a change notification for the Count property whenever an item is removed or added to the collection.

Cheers,
-dw

Now for my question:
Does binding to the ObservableCollection.Count property work (in a DataTrigger) ?
Ie. {Binding Path=Accounts.Count} where Accounts is an ObservableCollection.
What I assume is that since ObservableCollection does not implement INotifyPropertyChanged it will not work.

Thanks.

The short answer is yes, you can perform custom validation using a custom validation rule, but it’s almost always easier to perform such validation within the viewmodel class using IDataErrorInfo or IEditableObject (see ‘E’ is for Editable Collection).