Trigger question

Hi,

looking for some help for a trigger.
I need a trigger that starts an upgrading of a building if a hero gives (or sells or something like this) the building a special item.
Would be glad if someone can help me.

Thanks,

Drevlin

Place a region around the building you want to be upgraded then use the following trigger.

Events -
Unit - A unit enters (The region aound the building here)

Conditions -
(Owner of (Triggering Unit)) equal to (Whatever player controls the unit)
(Item-type of (Item carried by (Whatever Hero has it) in slot 1) Equal to (Whatever item you want this to be)

Actions -
Hero - Drop ( Item carried by (Hero carrying item) in slot 1) from (Hero carrying item)
Item - Remove last dropped item
Unit - Order (The building you want upgraded) to train/upgrade to a (Whatever you want the building to upgrade to)

And that should be it.