One way could be, hook On Saving Events and Cancel Saving on validation
http://world.episerver.com/blogs/K-Khan-/Dates/2015/5/hook-into-catalog-events/
Regards
/K

Thanks for the reply :)  That was one of my first ideas and in theory it would work.  One question though is that to add a varient to a node, I'm physiucally dragging varients over and using the link option when prompted, this updates and moves it automatically (reference here http://prntscr.com/8bt8go).

Does linking still call the published event even though I don't need to actually hit the publish button?

Hi,

With this approach, you will add handler for SavingContent (Not publishing events)

http://world.episerver.com/documentation/class-library/?documentId=cms/7/bcf6284c-22d0-5375-5b15-142b35138eb0

Regards
/K

Changes to Relations/Associations between nodes and entries can be listened via CatalogEventListenerBase http://world.episerver.com/documentation/Class-library/?documentId=commerce/8/1E7D1BBB . What I think that might work for you is:

- Implement an implemenation of CatalogEventListenerBase

- Override AssociationUpdating and RelationUpdating methods

- In these method, check if the changes satisfy your conditions or not.

Those events are ecf events, they work with DTO (CatalogRelationDto and CatalogAssociationDto).

Regards.

/Q

+1 for Quan's Solution.
/K

That looks promsiing, lathoguth my codes not getting hit.  How do i register it?  

I've got this

    public class MyCatalogEventListenerBase : CatalogEventListenerBase
    {
        public new void AssociationUpdating(object source, AssociationEventArgs args)
        {
            var variant = source as GameVariation;

            var boo = variant != null;
        }

        public new void RelationUpdating(object source, RelationEventArgs args)
        {
            var variant = source as GameVariation;


            var boo = variant != null;
        }
    }

and I also added in a structure map config but still nothign, is there somethign i'm missing?

            container.For<CatalogEventListenerBase>()
                .Use(ctx => new MyCatalogEventListenerBase());

Hi,

You are using "new". You should use "override" instead.

P/s: And you can use the attribute registration: [ServiceConfiguration(typeof(CatalogEventListenerBase)]

/Q

Perfect, thanks for your help.  That's got it working.  Last question though.. I can now do look-ups and prevent extra nodes, is there a recommened way that I can feed this back to the user?  I assume I'd write somethign like this :

        public override void RelationUpdating(object source, RelationEventArgs args)
        {
            var variant = source as GameVariation;


            var boo = variant != null;

            if (beep == NotUnderAnotherNode())
                base.RelationUpdating(source, args);

            else
                // Display Error Somehow
        }

In the CMS I'd use soemthig like IValidate to return a ValidationError, any suggestions?