I am working on a system that has been architected using the suggested model in Billy McCafferty's article on codeproject

http://www.codeproject.com/aspnet/NHibe ... ctices.asp

and am trying to integrate this with the use of the Microsoft Validation Application Block (VAB) found in the latest version of the Enterprise Library.

I had implemented this such that when my IInterceptor implementation called OnSave or OnFlushDirty, the associated entity was validated. At the end of all validation, if any object failed validation an exception was thrown with the collection of validation messages.

What I then found was that because I'm using the session-per-request model, Flush would usually be called in the EndRequest event on the HttpModule. As a result, the exception would be thrown, but thrown after all soap processing had taken place, and therefore outside of the boundary within which anything useful could be done with it. Instead of catching a relevant exception on the front end, an error relating to incorrect response type would be displayed.

The other option I looked into was to call validate on the entity in the call to SaveOrUpdate, but it is necessary to validate the entire entity hierarchy, not just the entity. Therefore using [ObjectValidator] would allow the validation to propagate to associated entities, but this does not respect lazy loading, and a mass of data would be loaded from the database to be validated.

I realise there are flaws in both of these approaches, but am trying to find an approach that will work.

I am trying to achieve a validation implementation where the validation can all be localized to the entity being validated, that is called automatically so that the developer doesn't have to call Validate() in his code, and that will allow for the collection and reporting of all validation errors (rather than one by one).

Has anyone successfully integrated the VAB with NHibernate and if so how?

anyone? any tips?

Are you implemented the IValidatable interface (4.5 in the reference documentation)?
You can also validate your business object using validation concept from the CSLA Framework (http://www.lhotka.net/Area.aspx?id=4)

No I'm not implementing IValidatable, as it was deprecated in 1.2, along with ILifecycle.




Thanks - will have a look into this.

There is a recent show on DNRTV showing you how to integrate CSLA with "other" Data Access tecnology. They are using "DTOs" to move the Data from their business object to the persistance layer. The real Validation would only take place in the business objects, and it would determine if the object gets passed to the persistance layer or not... (But this Validation logic is also available on the client, so you can avoid saving an invalid object anyway)

Also all your objects must inherit from a set of certain base classes, in order to gain most of their functions (Undo/Redo, Dirty Tracking, Business Rules etc...)

Also note, that the most current non-beta Version (2.1) has some heavy redesign on the broken rules collections. They now also implement a warning and information level, and now support short circuting...