Hi,
I'm new to NHibernate and am having difficulty getting it to work.

the following code causes the Mapping Exception "Duplicate class/entity mapping User";

string AssemblyName;
config = new Configuration();
AssemblyName=Assembly.GetExecutingAssembly().GetName().Name);
config.AddAssembly(AssemblyName);
config.AddClass(typeof(QuickStart.User));

The assembly is called quickstart and I have one class named User.

If I remove the config.AddClass statement I get the error:

"Unknown entity class: QuickStart.User"

when executing the session.Save(us) in the following code;

User us = new User();
...set properties before saving
ISessionFactory dal = new Configuration().BuildSessionFactory();
ISession session=dal.OpenSession();

ITransaction trans = session.BeginTransaction();
session.Save(us);

I have set the build action on the mapping file to embedded so thought the problem was not registering the classes at the start.

can anyone help with this as I am out of ideas.

thanks.

post your class and mapping file. it makes sense that you are getting a duplicate class error when adding the assembly and then adding the class explicitly.

-devon

Thanks,
in the interim I have sorted the problem. As you say, the duplicate makes sense, so I removed it.

After some digging around it seems I needed to make the properties on my class virtual.

thanks

yes, if the class is to be loaded lazily (through an association) then the methods must be virtual. classes are configured for lazily loading in two ways:

1) the association has a lazy="true" attribute:



2) the class mapping file itself has a lazy="true"