Entity Framework duplicating class when trying to insert related entity

Question

I have an ASP.NET application with a view trying to update an existing entity's title, price, and another bool and string. I have a simple one to many relation of Modifier_Categories and Modifiers. Each Modifier_Category can have many Modifiers. Modifier is the entity I'm trying to update.

When I call dbContext.SaveChanges() it updates the Modifier entity like I want but then for some reason duplicates and inserts its related Modifier_Category entity.

Nowhere in my functions can I find anywhere that instantiates a new instance of the related Modifier_Category and inserts it using the dbContext.Modifier_Category.AddObject();

Is there a way to figure out when the context is getting a new entity attached? How is the entity being added without me stating I want to add it?

Answer 1

If you're using MVC there could be some model binding occurring that's creating that Modifier_Category entity and attaching it to your Modifier model. There's not really a good way to find out unless you just step through the code until you find it. You need to look for any situation in which your Modifier model has a Modifier_Category object added to it not just for that Modifier_Category object to be added to the context, because when you add/attach the Modifier entity it's going to try to add/attach any related objects tacked on to that model*.

*Provided those objects haven't been marked as not mapping back to your database