从数组中筛选出我的对象会得到一个空数组

这是我的函数，我第一次使用ophalencontact（）在这些联系人被放入我的类中之后，为了从我的DB中检索联系人，我将它们放在一个数组中（因为1个"klant"可以有多个联系人）

现在我想把我的联系人放入我的"klant（客户）"中，并使用过滤方法

$contact= array();
foreach($contactlijst as $CT ){
    if($key['idklanten']==$CT->getklantID()){
        array_push($contact,$CT);
    }
    else{$contact="";}
}

我想可能是这个功能出了问题，有人能帮我吗？代码不会出现调试错误，但当我在网站上呈现它时，它会给我一个空数组。

提前谢谢。

function ophalen(){
    $this->ophalencontact();
    $dbh = new pdo( 'mysql:host=localhost;dbname=nextlead_spreker','nextlead_spreker', 'xxxxxx',array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));
    try {$sth = $dbh->prepare("select * from klanten;");
        $sth->execute();
        $row = $sth->fetchAll(PDO::FETCH_ASSOC);
        $lijst =array();

        foreach($row as $key){
            $contact= array();
            foreach($contactlijst as $CT ){
                if($key['idklanten']==$CT->getklantID()){
                    array_push($contact,$CT);
                }
                else{$contact="";}
            }
            $I= new Klanten($key['idklanten'],$key['naam'],$key['adres'],$key['postcode'],$key['stad'],$contact);
            array_push($lijst,$I); 

        }
        return $lijst;
    }
    catch(PDOException $ex){
        print_r($ex);
        die(json_encode(array('outcome' => false, 'message' => 'Unable to connect')));
    }  
}
function ophalencontact(){
    $dbh = new pdo( 'mysql:host=localhost;dbname=nextlead_spreker',      'nextlead_spreker', 'xxxxxxx',array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION));
    try {$sth = $dbh->prepare("select * from contactpersoonklant;");
        $sth->execute();
        $row = $sth->fetchAll(PDO::FETCH_ASSOC);
        $contactlijst =array();
        foreach($row as $key){
            $CT= new klantContact($key['idcontactpersoonklant'],$key['Voornaam'],$key['tussenvoegsel'],$key['achternaam'],$key['tel'],$key['email'],$key['klanten_idklanten']);
            array_push($contactlijst,$CT); 
            print_r($contactlijst);
        }
        return $contactlijst;
    }
    catch(PDOException $ex){
        print_r($ex);
        die(json_encode(array('outcome' => false, 'message' => 'Unable to connect')));
    }  
}