Guild Wars 2

If I use,say,Dagger Storm on a combo field,it only triggers once right?

It will only send 1 bolt of X (Fire bolts,Stunning bolts,etc..) or it will keep throwing bolts until it ends?

Because the “Whirl Combo” thingy only appears once,when you trigger it

Yeah, it only triggers once. But it triggers once per player that shoots through the combo field, so if there were a bunch of you using Dagger Storm on a combo field, the target would receive multiple affected bolts.

No, whirl finishers actually throw out bolts for as long as the skill is being channelled. A guardian using Whirling Wrath on his own Symbol of Wrath is a very good example.