Using NHibernate ActiveRecord and LINQ

I'm trying to learn NHibernate ActiveRecord and LINQ all in the same day. I ran into the following exception:

Session is closed!
Object name: 'ISession'.

When trying to execute the following code:

      public static User FindByUserName(string username)
      {
          // Note that we use the property name, _not_ the column name
          return (from p in User.Queryable
                  where p.Username == username
                  select p).First();
      }

It took me a couple hours to get by this one, so I thought I would post it. I had to wrap it in a using (new SessionScope()) statement. Like this:

       public static User FindByUserName(string username)
       {
           using (new SessionScope())
           {
               // Note that we use the property name, _not_ the column name
               return (from p in User.Queryable
                       where p.Username == username
                       select p).First();
           }
       }

Happy Coding.