Hi,

I'm using NHibernate and C#. I've problem using the 'lazy' directive. When I try to access a set (in the case below, is the parentDocs of the Document class) which has lazy set to true, I hit error (the error line is on the om.parentDocs.Count) stating that system use lazy instantiation since there is no session available. As such, I've added line to open/get the session again (see=NHibernateSessionUtil.Session will give open session). But this doesn't help.

Hope you guides tell me which area I should take note/modify when I set to 'lazy'? Or my code can't call like this (i.e. om.parentDocs.Count is invalid) or I need to explicitly call a HQL query to get the count result?

thanks in advance,
jL

code below:
public ArrayList getRootParentDocs(Document om)
{
ArrayList alResult = new ArrayList();
Document doc = new Document();
sess = NHibernateSessionUtil.Session;
ITransaction tx = sess.BeginTransaction();

if (om.parentDocs.Count == 0)
{
alResult.Add(om);
tx.Commit();
sess.Close();
}
else {
for (IEnumerator ie = om.parentDocs.GetEnumerator(); ie.MoveNext(); )
{
doc = (Document)ie.Current;
getRootParentDocs(doc);
}
sess.Close();
}
return alResult;
}

You have to keep the same session open in order to use lazy loading. Usually to achieve this people implement some kind of Unit of Work pattern to cleanly know when to flush and close the session.

In a web app, typically this is done in the begin/end request. Begin request opens the session, end request flushes and closes it. Anything in between gets the same session, so lazy loading works fine.

HTH. Lazy loading is a tough subject to learn in NHib.