Preventing listpicker items from showing

i want to prevent lispicker items from displaying when it is touch unless a condition is met.
i am using list picker to display available bluetooth list and if the screen initialize and the bluetooth is ON the command works but after pressing the phone's back button then the command don't work again.
any help?

What happens when you do this ? Does this disconnect your bluetooth ?

no bluetooth don't disconnect, but even if the condition is not met the list picker items displays.

You are doing this visibility work only in the touchdown event.

maybe do it in a repeating Clock Timer?

i try using repeating clock timer but with that the notifier massage is constantly showing once the selection has not been made, what i want is when the user press the listpicker and the selection is not made then the notifier show the massage.

I would avoid using a Notifier in the middle of a selection component's processing.
A Label would be less intrusive to the component's workflow.