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in Technique[技术] by (71.8m points)

Entity Framework: Re-finding objects recently added to context

I am using the entity framework and I'm having a problem with "re-finding" objects I just created... basically it goes like this:

string theId = "someId";

private void Test()
{
  using(MyEntities entities = new MyEntities())
  {
    EntityObject o = new EntityObject();
    o.Id = theId;
    entities.AddToEntityObject(o);
    CallSomeOtherMethod(entities);
  }
}

void CallSomeOtherMethod(MyEntities ents)
{
  EntityObject search = ents.EntityObject.FirstOrDefault(o => o.Id == theId);
  if(search == null) 
  {
    Console.WriteLine("wha happened???");
  }
}

(no guarantee the code works btw - it's all from my head)

Why doesn't the query "find" the EntityObject that was just created?

If I call SaveChanges() after the AddToEntityObject it works (which doesn't surprise me) but why doesn't it pull from the cache properly?

I'm still green on this stuff so I'm hoping that there's some really easy thing that I'm just overlooking...

Thanks

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by (71.8m points)

The newly added object is in the local DataSource, since it's not persisted yet in the database,

so you may say:

EntityObject search = ents.EntityObject.FirstOrDefault(o => o.Id == theId) ??
                      ents.EntityObject.Local.FirstOrDefault(o => o.Id == theId);

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