NHibernate: At what scope I should use transaction?

Question

I am developing Data Access Layer using NHibernate. It will be used in my Business Logic Layer. My application is collection of multiple other applications (ASP.NET MVC, Windows

Answer 1

Why not make the service(s) transaction aware?

something like

    protected virtual TResult Transact(Func func)
    {
        if (_session.Transaction.IsActive)
            return func.Invoke();

        TResult result;
        using (var tx = _session.BeginTransaction(IsolationLevel.ReadCommitted))
        {
            result = func.Invoke();
            tx.Commit();
        }

        return result;
    }

    protected virtual void Transact(System.Action action)
    {
        Transact(() =>
        {
            action.Invoke();
            return false;
        });
    }

in your service or repo that checks if a transaction is active and participates in an active one or creates a new transaction if non exists.

Now you can compose multiple service calls together under one transcation instead of having each call in isolation.