Solved Is it possible to cancel player changing slot?

I have a attempt for this butit failed, and i dont know whats going on. I search for this problem around the internet, but i still didnt get it
here's my code

PHP:

 public function onInventoryTransaction(InventoryTransactionEvent $event){
        $transaction = $event->getTransaction();
        $player = $transaction->getSource();
        $action = $transaction->getActions();
        if($action instanceof SlotChangeAction){
            $event->setCancelled();
         }
     }


sorry if my code was bad, cuz am new hehe

 

Based off what I can see getActions() returns an
array of actions, so checking if an array is an instance of SlotChangeAction will always result in false.
You can var_dump($action) to see what it is and how to achieve your goal

 

so how's var_dump do and how can i use it?
also, can i use other method to achieve my goal than this? so if i failed i can use other method

 

ups i was fixing my own problem UwU

PHP:

public function noInvMove(InventoryTransactionEvent $event){
        if($this->getServer()->getLevelByName("world")->getPlayers()){
         $event->setCancelled();
        }
    }


UwU, well i didnt even expain all in the thried yet but ok UwU