问题
Is there a way to query or just access newly added object (using ObjectContext.AddObject method) in Entity Framework? I mean situation when it is not yet saved to data store using SaveChanges
I understand that queries are translated to underlying SQL and executed against data store, and it don't have this new object yet. But anyway, I'm curious - if it is not oficially supported, maybe it is possible in theory. If it's not, how developer can deal with it? Manually track new objects and query them using Linq to objects?
The same question also applies to LinqToSql.
回答1:
In EF, if you use this code, you have all the entities that are already loaded in the context (including newly added ones) :
context.ObjectStateManager.GetObjectStateEntries(EntityState.Added | EntityState.Modified | EntityState.Unchanged).Select(o => o.Entity).OfType<YourObjectType>()
回答2:
"The same question also applies to LinqToSql."
For LINQ-to-SQL, look at DataContext.GetChangeSet(); this has 3 separate collections for the pending .Inserts, .Updates and .Deletes
Note that the ChangeSet is a snapshot of when the GetChangeSet() method is called; you need to re-query to see any additional changes.
来源：https://stackoverflow.com/questions/326186/is-query-to-new-added-object-possible-in-ms-entity-framework