enchanting Question

I frequently dual farm tthe UW with an Ss necro and had a question about enchanting. To get the bonus, do I have to be holding the wpn with the 20% enchanting mod when I cast it, or can I switch weapons TO the enchanting weapon and still get the bonus.

Just wonderin. Thanks.

i think you have to wield it then cast a spell, not the other way around

The weapon needs to be equipped at the time of casting to have any effect.

Yes, Natalie is correct, however once the spell is cast you can immediately switch off the weapon and it will still have the extended time.