InsertOnSubmit not attached?

Question

After creating a new object (Foo), I set the key (BarId) for the association property EntityRef (Bar). Then I want to insert a new object into the database and after that access the lazy loaded child.

Unfortunately, the lazy-load property returns null after calling InsertOnSubmit (). It returns the correct object if I instead bind () the object to a data context.

Here is the code that successfully inserts my new object into the database, but incorrectly configured lazy loading for the property of the child bar:

var foo = new Foo();
foo.BarId = 123;
context.GetTable<Foo> ().InsertOnSubmit( foo );
foo.Bar.Something();    // throws NullReferenceException

Here the Bar object is loaded correctly:

var foo = new Foo();
foo.BarId = 123;
context.GetTable<Foo> ().Attach( foo );
foo.Bar.Something();    // method is called on lazy-loaded Bar object

The Attach call before InsertOnSubmit causes the latter to throw an exception "Cannot add an entity that already exists."

, LINQ-to-SQL, ?

?

Answer 1

Bar BarId Foo. , , Linq-to-sql , , BarId. . , - :

var foo = new Foo();
foo.Bar = //get bar with id: 123;
context.GetTable<Foo> ().InsertOnSubmit(foo);
foo.Bar.Something();