Question

I know I can manually set each Id property to assigned using Assigned().

Is there any way of applying this globally, as I want to do it on every entity?

Answer 1

Sure, just register FluentNHibernate convention like this:

public class AssignedIdConvention : IIdConvention
{
    public void Apply(IIdentityInstance instance)
    {
        instance.GeneratedBy.Assigned();
    }
}

Registration goes like this:

Fluently.Configure()
    .Mappings(...)
    .Conventions.Add<AssignedIdConvention>()