I'm gradually realizing that in order to provide a Save/Cancel button I need an NPersist style N-level cache. What I need is to be able to create a copy of a business object that behaves exactly like an NHibernate proxy (duplicates child collections lazily) but with an in-mem object as it's datastore, not the database. Any way I can accomplish this myself today by creating my own proxy. Seems a shame to roll my own given how similar this is to Nhibernate's functionality.

Am I barking up the wrong tree? How do other people provide a Save/Cancel features?

I use a struct as my backing datastore (and properties to retrieve it). Then I implement IEditable and in the corresponding BeginEdit() I make a copy of the struct to a temp location.
When CancelEdit() is called, i just replace the 'current' struct with the temp struct.
If endedit is called, I just dispose the temp struct.

This is how microsoft recommends doing it.

I hope that helps

The problem with disposing of the NHibernate business object returned from the session and replacing it with a new one is that the business object returned by the session is actually an NHibernate proxy with special collections that remember what changes have been made. If I simply try and update NHibnerate with the copy when the user clicks "Save" NHibernate will attempt to insert all the objects in the child collection (I think?). I tried to ask this question earlier in the forum and I didn't get a response:

If I make a binary copy of an NHibernate proxy (via binary serialization), dereference the original, and call session.Save on the copy will the behaviour be the same as if I called session.Save on the NHibernate proxy?

In other words: Does the session store a pointer to the retrieved object in the cache or does it simply use the ID?

Thanks,
Jafar