何时在ASP.NET MVC 2应用程序中提交NHibernate事务？

类似的东西(这是从我的架构的不同部分一起被黑客攻击)：

public class TransactionalAttribute : ActionFilterAttribute,IAuthorizationFilter,IExceptionFilter
{

    ITransaction transaction = NullTransaction.Instance;
    public IsolationLevel IsolationLevel { get; set; } 

    public TransactionalAttribute() 
    {
        IsolationLevel = IsolationLevel.ReadCommitted;
    }

    public override void OnResultExecuted(ResultExecutedContext filterContext)
    {
        try
        {
            transaction.Commit();
            transaction = NullTransaction.Instance;
        }
        catch (Exception exception)
        {
            Log.For(this).FatalFormat("Problem trying to commit transaction {0}",exception);
        }

    }

    public override void OnActionExecuting(ActionExecutingContext filterContext)
    {
        if (transaction == NullTransaction.Instance) transaction = UnitOfWork.Current.BeginTransaction(IsolationLevel);
    }

    public override void OnActionExecuted(ActionExecutedContext filterContext)
    {
        if (filterContext.Result != null) return;

        transaction.Commit();
        transaction = NullTransaction.Instance;
    }

    public void OnAuthorization(AuthorizationContext filterContext)
    {
        transaction = UnitOfWork.Current.BeginTransaction(IsolationLevel);
    }

    public void OnException(ExceptionContext filterContext)
    {
        try
        {
            transaction.Rollback();
            transaction = NullTransaction.Instance;
        }
        catch (Exception exception)
        {
            Log.For(this).FatalFormat("Problem trying to rollback transaction {0}",exception);
        }
    }

    private class NullTransaction : ITransaction
    {
        public static ITransaction Instance { get { return Singleton<NullTransaction>.Instance; } }

        public void Dispose()
        {

        }

        public void Commit()
        {
        }

        public void Rollback()
        {
        }
    }
}