Implementing auto-save in WPF / MVVM / NHibernate

Question

My client likes programs like Microsoft OneNote where changes are saved automatically, and he can choose to discard when he explicitly wants to do so. I will have to implement some undo functionality, but I'll figure that out some other time.

With NHibernate, I suppose I can call ISession.Update on every single property / binding change, but I can see real pain with this approach down the road. I am not a fan of timers, but maybe a 5 second timer that starts on property / binding change and at timer end use BackgroundWorker thread to save to db.

What do you think?

Answer 1

A ISession.Update on every property-change isn't a good idea normally. The property-change-events are fired quite often. It could slow down your application when you do ISession.Update on every change. This will probably lead to a bad user experience.

In our Application has the same behavior. We store the changes when a View is closed (an some other related event). For example when the user closes a tab, the data which was displayed in that tab is closed.

An additional timer is probably a good idea to prevent data loss when the application crashes / unexpected happens.