I working on a project that uses NHibernate. My problem is when I'm trying to add an object that contains a list of objects I receive the following exception:
Illegal attempt to associate a collection with two open sessions from Session.Save method
I don't know what is the problem or how to solve it, please if any one can help I will appreciated.
It seems that objects you try to add were loaded from different session that the destination object into which you are attaching them.
You are having session management problems. It seems that you are using an object from one session as collection item in a collection from some other session. Using multiple parallell sessions is usually not a good practice (at least not from the same thread).
Read up on Unit of Work here; http://blogs.hibernatingrhinos.com/nhibernate/archive/2008/04/10/nhibernate-and-the-unit-of-work-pattern.aspx .
There is an excellent and free implementation of this in Rhino.Commons, you can read more about that here: http://ayende.com/blog/archive/2007/06/08/rhino-commons-repositorylttgt-and-unit-of-work.aspx.