Key System

I need to know how to implement a key system into my map via triggers / items, it has to follow the rules:
-Hero must be carrying key in slot (1-6)
-May only carry one key of it's type
-Will enable "close/open" "X" text triggers (player types, Close Bar, and the bar is closed, same if he said open)

I'm just not sure how to check if they are carrying item. Note the hero nore the item are not pre-place, and cannot be pre-placed.

there is a trigger to do all of this, look in WE

Isnt there a boolean "Hero Has item of type"?

I looked i couldn't do it, i need help, please give me it in this form:

Event
EXACT TRIGGER LINE
Condition
EXACT TRIGGER LINE
Action
EXACT TRIGGER LINE

-or-

you could guess make a map with it working for one area and ill use it as tut...

any1?

variables used are
Hero[array] = unit
Gate = destructable

Event-
Player 1 types chat message = open bar as exact match
Player 2 types chat message = open bar as exact match
Player 3 types chat message = open baras exact match
Ect
Condition -
Hero[number of triggering player] has item = item of type Bar Key
Action-
Destructable - open gate = Gate

that should do it

...Also, if you already have your other text triggers setup and don't want to give Dark Alucard's method a shot (not trying to out-do you Dark, just giving an alternate suggestion ;)), maybe:

Events
Unit - A unit enters [Pre-defined Gate Region]
Conditions
(Item-type of (Item carried by (Triggering unit)
in slot 1)) Equal to [Your Key]
(Item-type of (Item carried by (Triggering unit) in slot 2)) Equal to [Your Key]
(Item-type of (Item carried by (Triggering unit) in slot 3)) Equal to [Your Key]
---------- etc ----------
Actions
Trigger - Turn on [Your Text Trigger]

Read Alucard's post below mine :P. You need to chain each Condition with an OR (simple enough :)).

[edit] Spelling ;p
[EDIT 2] Thanks Alucard :). I do most stuff straight in JASS myself, so I couldn't remember if Conditions chained themselves as ORs automatically or not :).

that would work DescX but Ox if you do what he said you also need to put the OR(multiple condtions) condition, or the unit would need a full inventory of keys

OR open the war chasers and check out their perfect key system