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Deleting entities using another collection

Printed From: IdeaBlade
Category: DevForce
Forum Name: DevForce 2010
Forum Discription: For .NET 4.0
URL: http://www.ideablade.com/forum/forum_posts.asp?TID=2723
Printed Date: 31-Oct-2025 at 2:19am


Topic: Deleting entities using another collection
Posted By: Randar
Subject: Deleting entities using another collection
Date Posted: 26-May-2011 at 3:28pm
What I'm trying to do is:
1) Keep track of the entities that need to be deleted in a List(Of T As IdeaBlade.EntityModel.Entity)
2) When the person actually hits the "save", take that list and actually delete the entities along with a bunch of other data.

I tried to create a new EntityManager and then take my list of entities and called .EntityAspect.Delete on them.  No big surprise, but they didn't get deleted because they originally belonged to a different EM.

Is there a way I can take those entities and attach them to the new EM and then delete them when I hit SaveChanges?  I'm just trying to not re-retrieve them from the server if I can.

I hope I explained myself well enough.

In case you ask, there are reasons, that would take a while to explain, but I can't just flag the entity at the time of deletion using .EntityAspect.Delete.  I have to keep track of the list.


Replies:
Posted By: robertg
Date Posted: 26-May-2011 at 3:45pm
Randar,
 
Have you considered adding a property to the entity with a partial class, and using that property to track entities you want to delete? Then, when it's time to save your changes, you can first run a query for that property, and delete each of the entities that match it. It's much more straight-forward than storing information about those entities in another object.
 
-- Robert

Posted By: Randar
Date Posted: 26-May-2011 at 3:51pm
Hmmm...wouldn't that accomplish the same thing as just keeping them in a list?  If I had a flag, I would have to keep them around for a while.  The problem is the time between the flagging and the call to SaveChanges may be some time apart.  I have an entity that was associated with with one EM and trying to delete it a different EM.  Are you saying that is possible and happens by default?

If so, I have to look through my code again and find out why they are not actually being deleted.

Posted By: robertg
Date Posted: 26-May-2011 at 4:00pm
It's not quite the same thing... if you're extending the entites so that you can use them to track their own state, you never have to worry about having extraneous copies of them, or merging anything. You'd just have one EM, and can thus keep it simple.

Posted By: robertg
Date Posted: 26-May-2011 at 4:44pm
Hey, Albert just filled me in a little on your project, and I understand why you'd want to use the original described behavior if it's a big conversion project. It sounds like you have the information you need now, but if there's anything else, please let us know.


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