I am using ASP.net with the session-per-request pattern.

I found the need to implement lazy loading, which isn't a problem for most of my app except for in 2 places where I have a wizard-style interface. (multi-page transaction). The lazy load fails here because I need the same session that the original object was created on, but in this case it's on a separate page so the session is gone.

What I did was add a method to by base class to allow to mark an object as "Floating" which basically puts the current ISession into HttpSession. The session-per-request pattern is now bypassed and the site works on session-per-httpsession pattern (until I tell it to stop). This part works when lazy loading is turned off... the site behaves exactly as before.

When I turn lazy loading back on, I get the same error, only this time I KNOW that the current ISession is the same as the one that the object was loaded on.

Can anyone help me figure out what is wrong? Without lazy loading my entire object graph is loaded into memory, which will be a problem in production.

TIA.

just a thought -- will a lazy loaded collection RECONNECT a session that is open but disconnected?

I know it won't work if the session is closed, but I am disconnecting the session after a save/update/delete, so this may be the cause of the problem.

I think you'll run into threading issues if you leave the ISession in the HttpSession, even if you Reconnect() and Disconnect().

A couple of suggestions:

1) You can always hack around the lazy-load issue if you know ahead of time what parts you're going to need to load by accessing them at the time you first load the object.

Parent p = session.Get(typeof(Parent), parentID);
int throwaway = p.Children.Count; // force lazy-load of Children collection.

2) If you're not editing the object that is giving you the lazy-load issue in your multi-page transaction, you can just do a session.Refresh() on the object in question. This will reload its state from the DB and reassosciate it with the session.

3) If you're dealing with a bi-directional assosciation, you can work with the child objects alone and then just refresh the Parent object at the end.

i.e. instead of...
Parent p = session.Get(typeof(Parent), parentID);
// next request
p.AddChild(newChild); // this would give you the lazy-load exception

you do...
Parent p = session.Get(typof(Parent), parentID);
// next request
Child newChild = new Child();
newChild.Parent = p;
// do not add newChild to p.Children
// next request
session.Save(newChild);
session.Refresh(p); // p.Children now includes newChild

4) Look into ISession.SaveOrUpdateCopy(). I've never used it and I'm not sure precisely what it does, but it might have something to do with a solution to your problem.

OT: Are you from Ars?

Threading issues? why?

(I'm not really worried about this because it's an admin interface not a public page... only 1 user at a given time).

As of right now I'm getting the no session error if I try what you suggest at # 1). I'm not sure why. When I access the collection property, I check the current session and IsConnected is true, and IsOpen is false... this is quite odd!

2) I am editing the parent object, so I don't think this will work for me.

Thanks for the reply.

OT: what's ars?