ObjectSet query not returning added EntityObject until SaveChanges() called

Question

I think I'm missing something very simple here.

I have an EF4 ObjectContext that contains an ObjectSet of type Thing, which is mapped to a table in my database called Things. If I add a Thing to the Things ObjectSet, that Thing is not visible in Things until I call SaveChanges() on the ObjectContext.

So, in the following test fixture, AddToThings_AddsItemsToContext_WithSaveChanges passes but AddToThings_AddsItemsToContext_WithoutSaveChanges fails:

[TestFixture]
public class Ef4Tests
{
    [SetUp]
    public void SetUp()
    {
        var ef4PocEntities = new Ef4PocEntities();
        ef4PocEntities.DeleteDatabase();
        ef4PocEntities.CreateDatabase();
    }

    // this test passes
    [Test]
    public void AddToThings_AddsItemsToContext_WithSaveChanges()
    {
        var ef4PocEntities = new Ef4PocEntities();
        Assert.AreEqual(0, ef4PocEntities.Things.Count());

        ef4PocEntities.AddToThings(new Thing {Name = "Bob"});
        ef4PocEntities.SaveChanges();
        Assert.AreEqual(1, ef4PocEntities.Things.Count());
    }

    // this test fails
    [Test]
    public void AddToThings_AddsItemsToContext_WithoutSaveChanges()
    {
        var ef4PocEntities = new Ef4PocEntities();
        Assert.AreEqual(0, ef4PocEntities.Things.Count());

        ef4PocEntities.AddToThings(new Thing {Name = "Bob"});
        Assert.AreEqual(1, ef4PocEntities.Things.Count());
    }
}

Is there a way to do what I want? I.e. add Entities to an ObjectSet and have them visible without saving to the database?

Answer 1

The answer is here: http://stackoverflow.com/questions/2716359/help-me-understand-entity-framework-contexts-please.