title: How to manage NHibernate sessions in a long lived Windows forms application?
body: <p>We are using NHibernate to manage our persistence in a complex modular windows forms application - but one thought keeps bothering me. We currently open a session on launch and open all objects through that session. I am worried that all loaded objects get loaded into the NHibernate session cache, so that they cant be garbage collected, and ultimately we will end up with the whole database in memory.</p>
  
  <p>This never happens with web applications because web page requests (and even better Ajax requests) represent the perfect short lived transaction so a session can be opened and closed to handle each request.</p>
  
  <p>However if I load an tree of objects in my forms application and put then into a navigation pane on the screen they may stay their for the life of the application - and at any point the user may click on them, resulting in our code needing to navigate the object relationships to other objects (which only works within an NHibernate session).</p>
  
  <p>What do StackOverflow readers do to keep the benefits of NHibernate without the issues I describe?</p>