my appliction post the following error:
The hibernate.connection.driver_class must be specified in the NHibernate configuration section


my configure file:
<?xml version="1.0" encoding="utf-8" ?>
<hibernate-configuration xmlns="urn:nhibernate-configuration-2.0" >
<session-factory name="NHibernate.Test">
<!-- properties -->
<property name="hibernate.connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
<property name="hibernate.connection.driver_class">NHibernate.Driver.SqlClientDriver</property>
<property name="hibernate.connection.connection_string">Server=localhost;initial catalog=leopold;User ID=leopold;Password=password;Min Pool Size=2</property>
<property name="show_sql">false</property>
<property name="dialect">NHibernate.Dialect.MsSql2000Dialect</property>
<property name="use_outer_join">true</property>
<property name="query.substitutions">true 1, false 0, yes 'Y', no 'N'</property>
<!-- mapping files -->
<mapping assembly="Demo" />
</session-factory>

</hibernate-configuration>



and I put this file in the root direction of the assembly;

please help

"in the root direction of the assembly" ???
I assume that you are using Configuration.Configure().

You must put the "hibernate.cfg.xml" in your "working" directory, that is where your compiled assemblies are (like /bin/Debug/ or /bin/Release/).

You can put it in your project directory (where your source code is) and add:

in the properties of your project (in "PreBuildEvent" or "PostBuildEvent")