无法实例化连接提供程序：NHibernate.Driver.MySqlDataDriver

Question

I'm making a simple web project using NHibernate and i'm stuck at this error whenever i try to build the sessionfactory.

The line that causes the exception is this

ISessionFactory sessionFactory = new Configuration().Configure().BuildSessionFactory();

People with similar problem seems to solve them by referencing Mysql.data.dll which i've already done, and checked that the dll is in my bin folder.

i suspect the fault lies in my hibernate.cfg.xml which looks like this

<hibernate-configuration xmlns="urn:nhibernate-configuration-2.2">
<session-factory>
<property name="dialect">NHibernate.Dialect.MySQLDialect</property>
<property name="connection.provider">NHibernate.Driver.MySqlDataDriver</property>
<property name="connection.driver_class">NHibernate.Driver.SqlServerCeDriver</property>
<property name="connection.connection_string">connectionstring</property>
<property name='proxyfactory.factory_class'>NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle</property>
<mapping assembly="Mcgvd" />
</session-factory>
</hibernate-configuration>

the tutorial i followed to make this project was using a helperclass to create the sessionfactory looking like this

public sealed class NHibernateHelper
{
    private const string CurrentSessionKey = "nhibernate.current_session";
    private static readonly ISessionFactory sessionFactory;

    static NHibernateHelper()
    {
        sessionFactory = new Configuration().Configure().BuildSessionFactory();
    }

    public static ISession GetCurrentSession()
    {
        HttpContext context = HttpContext.Current;
        ISession currentSession = context.Items[CurrentSessionKey] as ISession;

        if (currentSession == null)
        {
            currentSession = sessionFactory.OpenSession();
            context.Items[CurrentSessionKey] = currentSession;
        }

        return currentSession;
    }

    public static void CloseSession()
    {
        HttpContext context = HttpContext.Current;
        ISession currentSession = context.Items[CurrentSessionKey] as ISession;

        if (currentSession == null)
        {
            // No current session
            return;
        }

        currentSession.Close();
        context.Items.Remove(CurrentSessionKey);
    }

    public static void CloseSessionFactory()
    {
        if (sessionFactory != null)
        {
            sessionFactory.Close();
        }
    }
}

hibernate.cfg.xml and hibernate.hbm.xml are both located at the root of my project.

What am I doing wrong here ?

Answer 1

Your configuration is wrong.

<property name="connection.provider">NHibernate.Driver.MySqlDataDriver</property>
<property name="connection.driver_class">NHibernate.Driver.SqlServerCeDriver</property>

You've specified a driver for the connection provider, and a SQL Server CE driver when you're apparently using MySQL. Try:

<property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
<property name="connection.driver_class">NHibernate.Driver.MySqlDataDriver</property>

Answer 2

besides the fault Jamie found i had to change the connection.provider property where i for some reason had put mysqldatadriver.

this is the working configuration i ended up with.

<hibernate-configuration xmlns="urn:nhibernate-configuration-2.2">
<session-factory>
<property name="dialect">NHibernate.Dialect.MySQLDialect</property>
<property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property>
<property name="connection.driver_class">NHibernate.Driver.MySqlDataDriver</property>
<property name="connection.connection_string">connectionstring</property>
<property name='proxyfactory.factory_class'>NHibernate.ByteCode.Castle.ProxyFactoryFactory, NHibernate.ByteCode.Castle</property>
<mapping assembly="Mcgvd" />
</session-factory>
</hibernate-configuration>