Hello everyone,

I am just getting started with NHibernate, and I cant seem to get the quickstart demo running as described at:
http://www.hibernate.org/hib_docs/nhibe ... start.html.

The error I am getting is "Unknown entity class: QuickStart.Cat", which I believe means that NHibernate is not seeing my mapping file correctly. Other posts seem to point to the "embedded resource" problem in Visual Studio, but making that change did not seem to help anything. I also saw some mention that an error in the mapping file could cause this to happen, but since I copied/pasted right from the documentation, Im not sure how I could have got an error.

I took a screenshot of my project setup and mapping file in Visual Studio in case that might help determine what the problem is; that can be viewed by going here:
http://update.docutek.com/quickstart.gif

Im not sure what to try next, so I hope someone out there has some good ideas for me. So far getting started with NHibernate is taking much more effort than I had hoped, but Im not ready to give up yet!

Thanks in advance,

-Marc

What version of NHib are you using?
Also, please post your whole stack trace including any inner exceptions.

The mapping file is using nhibernate-mapping-2.0 where the latest version of Nhib should use nhibernate-mapping-2.2 in the xmlns.

MIKE

I have the same problem.
I use NHibernate 1.2.0 and if I change <hibernate-mapping xmlns="urn:nhibernate-mapping-2.0" to 2.2 I get an such error (QuickStart.Cat.hbm.xml(2,2): XML validation error: Could not find schema information for the element 'urn:nhibernate-mapping-2.2:hibernate-mapping'.) when I make AddAssambly to configuration. May be I should include schema in VS2005?

the main problem with ("Unknow class entity") occur in SessionFactoryImpl.cs owned by NHibernate.dll
GetEntityPersister method get the Cat class but result will get a null.
What can I do? Please help.
public IEntityPersister GetEntityPersister(System.Type theClass)
{
IEntityPersister result = classPersisters[theClass] as IEntityPersister;
if (result == null)
{
throw new MappingException("Unknown entity class: " + theClass.FullName);
}
return result;
}

I had the same problem as you, and as Mike mentioned the xml namespace in the new version is 2.2 and not 2.0 as indicated by the docs - changed this and it worked great.

I have changed the version to 2.2 still i am facing the same problem. Can any one help me on this?

Thanks,
RaviKumar

1-Make sure your mapping is correct
<class name="namespace.entityname, assembly name" table="tablename">

2- Make sure taht you have set the properties of hbm files as embedded Resource

This worked for me:D Resolved