Help Need to disable a Hero to Learn a certain hero ability.

How can I disable Learn button for a certain hero ability ?
I want it learn trough a certain event. not trough hero skill point.

I try to set learn ability Icon to None. but it's appear green when I play it.
Is Unit Ability(Non Hero) support multiple Level ?

Do you want the Hero to have to learn the ability, when the event goes off?? If not, then just add the ability to the hero when he triggers the event.

unit abilities can support multiple level. You could use upgrades to level up unit abilities and set level of upgrade in triggers which automatically increases level of ability. Or just increase level of the unit ability itself.

to azhag, it's multiple level ability, if I add it, to hero then the hero can learn the next level through skill point. which I don't want it.

to Strategy Master, I don't know how to used upgrade with unit(non hero) ability multiple level.
if you mean I have to create one unit ability for each level. it's too hard since i need to create 20 unit ability for a one type of ability( 20 Level )for a hero.
Is there a simple way ?

You can create a multi-level unit ability and give it to the hero. since it's a unit-ability, not a hero skill, the hero will not be able to level up the ability with the use of skill points. Instead, you can change the level of the ability with triggers (unit - set level of ability for unit (it's the last action on the unit-actions list))whenever you see fit.

thanx, I didn't notice if there is a unit set level of ability. (+1 rep)