Question

I have a module which retrieve a serialized nhibernate object from the dragged object :

DragObject dragObject = e.Data.GetData(typeof(DragObject)) as DragObject;
Object content = XamlServices.Load((new StringReader(dragObject.Xaml)));

But I get an exception in the second line saying :

failed to lazily initialize a collection, no session or session was closed

Answer 1

I assume your dragObject is the object which is serialized with nhibernate. Apparently the Xaml property is lazy loaded (or accesses a lazy loaded property of the class).

You need to load the dragObject in the same session where you access all lazy loaded properties:

using (ISession session = sessionFactory.OpenSession())
{
    DragObject dragObject = e.Data.GetData(typeof(DragObject)) as DragObject;
    Object content = XamlServices.Load((new StringReader(dragObject.Xaml)));
}

Alternatively you can also eager load the lazy properties.