Getting started: NHibernate + SQLExpress

[beantaxi]

Hello all,

I'm trying to write a simple program, using VS C# 2005 Express and SQL
Server Express with NHib 1.0.2. No matter what I try, I'm unable to
connect:

cannot open connection
at NHibernate.Impl .SessionFactory Impl.OpenConnec tion()
at NHibernate.Impl .SessionImpl.ge t_Connection()
at NHibernate.Tran saction.AdoTran saction.Begin(I solationLevel
isolationLevel)
(etc)
Below is my configuration, which seems straightforward to me.

<nhibernate>
<add key="hibernate. connection.prov ider"
value="NHiberna te.Connection.D riverConnection Provider"/>
<add key="hibernate. connection.driv er_class"
value="NHiberna te.Driver.SqlCl ientDriver"/>
<add key="hibernate. connection.conn ection_string" value="Data
Source=.\SQLEXP RESS;AttachDbFi lename=|DataDir ectory|
\testdb.mdf;Int egrated Security=True;C onnect Timeout=30;User
Instance=True"/>
<add key="hibernate. connection.isol ation" value="ReadComm itted" />
<add key="hibernate. dialect"
value="NHiberna te.Dialect.MsSq l2000Dialect"/>
</nhibernate>

"testdb.mdf " is the db file I created. For my connection string, I'm
actually using what VStudio itself generated, when I created a form
with a DataGridView on the same database. The DGV populated just fine,
but the same connection string in NHib seems to give me problems.

Does anyone have NHib + SQLServerExpres s working locally?

Thanks,
Taxi