EntityFramework show entities before saving changes

问题

Entity Framework ObjectSet with its method ToList shows just saved entities. That means, when I call

context.AddToCustomers(myNewCust);

and then (without calling SaveChanges)

myDataGrid.DataContext = context.Customers.ToList();

the DataGrid doesn't show the newly added entity (even context.Customers.Count() doesn't include it).

Is there any way to show these entities (those with EntityState = Added) ?

Thanks in advance.

回答1:

I think you can get unsaved added entities by calling something like:

var inserted = context.ObjectStateManager
                      .GetObjectStateEntries(EntityState.Added)
                      .Where(e => !e.IsRelationship)
                      .Select(e => e.Entity)
                      .OfType<Cutomer>();

But just by reading your question, I'm affraid that you are trying to do something wrong. Why do you need to combine unsaved entities with retrieved? If you need to show unsaved content you should simply keep it in your own separate collection.

回答2:

Look at the TryGetObjectStateEntry(EntityKey, ObjectStateEntry) method

http://msdn.microsoft.com/en-us/library/system.data.objects.objectstatemanager.aspx

来源：https://stackoverflow.com/questions/5455972/entityframework-show-entities-before-saving-changes