entity framework - DBContext Added/Attached Event?

Question

EF 4.1 RC. I want to run some code after an entity has been added/attached to the DBContext. Is there an event for this (I can't find one). Basically I want to check if the added/attached entity is of a certain interface and if it is, do some stuff with it. Thanks!

Answer 1

To track changes to the Context you can use the ObjectStateManagerChanged event of the ObjectStateManager. To access the ObjectStateManager, you have to use the IObjectContextAdapter for casting the DbContext like

var contextAdapter = ((IObjectContextAdapter)dbcontext);            
contextAdapter.ObjectContext
              .ObjectStateManager
              .ObjectStateManagerChanged += ObjectStateManagerChanged;

Once you got the event, it fires every time the collection gets changed by adding or removing entities to the ObjectStateManager. To track the state of the entity, use GetObjectStateEntry() of the ObjectStateManager and use the Element of the CollectionChangeEventArgs param.

Combining both states of CollectionChangeEventArgs and ObjectStateEntry you can track, what is going on....