I'm using NH to map DB to an object named `location` which has some properties and on List `<Attachments>` attachments (one-to-many relation with instance of `lcocation`).


I use lambda expression to init `location` istance:

public IList<T> GetAllByExpression(Expression<Func<T,bool>> expression)
{
using (ISession session = NHibernateHelper.OpenSession())
{
return session.Query<T>().Where(expression).ToList();
}
}

at some later point in the code I try to access `location.attachments` collection but get an exception:

> {"Initializing[Location#543c7367-08fa-4469-a252-8e2c6163be22]-failed
> to lazily initialize a collection of role: Location.Attachments, no
> session or session was closed"}

I understand the session is closed, but there is no much I can do.

I understand the session is closed, but there is no much I can do.

I have a dilema:
1) The code uses the collection after fetching from the DB and needs the session to still be open.
leaving the session open for the whole time is a bad practice. (without `using`).

2) Even if i leave the session open during the whole application runtime, I have build an n-tier web application.
The DAL should be general and not expose some implementation's session (NH in this case).

3) Eager loading seems to be the solution, but it's wastefull - as I'll have to eager load all the data in case of an object with list of other objects in it. (And that can even continue recurrsively)

What should I do?

TIA