Hi,

I have a problem (or maybe I'm the problem).
I've been working with NHibernate for a while now, and I learned it from the book NHibernate In Action.

I was looking for a solution to the problem of opening only one session per request, and that book gives the following solution:

public void Init(HttpApplication context)
{
context.BeginRequest += new EventHandler(Application_BeginRequest);
context.EndRequest += new EventHandler(Application_EndRequest);
}

private void Application_BeginRequest(object sender, EventArgs e)
{
ISession sesion = NHibernateHelper.AbrirSession();
sesion.BeginTransaction();
CurrentSessionContext.Bind(sesion);
}

private void Application_EndRequest(object sender, EventArgs e)
{
ISession sesion = CurrentSessionContext.Unbind(NHibernateHelper.FabricaSesion);

if(sesion != null)
try
{
sesion.Transaction.Commit();
}
catch (HibernateException ex)
{
sesion.Transaction.Rollback();
throw new Exception(Constantes.ERROR_TRANSACCION, ex);
}
finally
{
sesion.Close();
}
}

This works fine. The other day I was debugging my web application, and found out that when I refreshed de page (by clicking on a button), it entered here to end the request (Application_EndRequest), but it did it like 5 times. Is this correct?? Shouldn't do it only once, and inmediately then enter the Application_BeginRequest method and open one and only one session??

I'm thinking of this as a problem because of the following:

I have a class which contains a list of objects of the same class. I add and remove objects from that list, and then I save de object. Sometimes it works fines, but on others it triggers the following message error: unexpected row count 0 expected 1.
Especially when it happens the following: I delete a Contact from the list, save it (which does OK), and next I add a Contact to the list and save it (throws this error)

Here is the code of my Entity:
Contact
{
//........//
private Contact parentContact;
private IList<Contact> sons = new List<Contact>();

public virtual Contact ParentContact
{
get { return parentContact; }
set { parentContact = value; }
}

public virtual IList<Contact> Sons
{
get { return sons; }
}

public virtual void AddSon(Contact son)
{
son.ParentContact = this;
Sons.Add(son);
}

public virtual void DeleteSon(Contact son)
{
son.ParentContact = null;
Sons.Remove(son);
}
}

And the property mapping is the following:

<bag name="Sons" inverse="true" cascade="all-delete-orphan" lazy="true" access="nosetter.camelcase">
<key column="ParentContact" />
<one-to-many class="Contact" />
</bag>

I use the two convenience methods from above to add and delete contacts from the list. Am I doing something wrong???
If you need more info please let me know.

Thanks a lot!

Sebastian