entity framework - Querying objects after AddObject before SaveChanges?

Question

In EntityFramework, is that possible to query the objects that have just been added to the context using AddObject but before calling the SaveChanges method?

Thanks

Answer 1

To persist an entity you usually add it to it's DbSet in the context.

For example

var bar = new Bar();
bar.Name = "foo";
var context = new Context();
context.Bars.Add(bar);

Surprisingly, querying context.Bars, the just added entity cannot be found

var howMany = context.Bars.Count(b => b.Name == "foo");
// howMany == 0

After context.SaveChanges() the same line will result 1

The DbSet seems unaware to changes until they're persisted on db.

Fortunately, each DbSet has a Local property that acts like the DbSet itself, but it reflect all in-memory operations

var howMany = context.Bars.Local.Count(b => b.Name == "foo");
// howMany == 1

You can also use Local to add entities

context.Bars.Local.Add(bar);

and get rid of the weird behavior of Entity Framework.