protected function prepareKeys($models)
{
$keys = [];
if ($this->key !== null) {
foreach ($models as $model) {
if (is_string($this->key)) {
$keys[] = $model[$this->key];
} else {
$keys[] = call_user_func($this->key, $model);
}
}
return $keys;
} elseif ($this->query instanceof ActiveQueryInterface) {
/* @var $class \yii\db\ActiveRecord */
$class = $this->query->modelClass;
$pks = $class::primaryKey();
if (count($pks) === 1) {
$pk = $pks[0];
foreach ($models as $model) {
$keys[] = $model[$pk];
}
} else {
foreach ($models as $model) {
$kk = [];
foreach ($pks as $pk) {
$kk[$pk] = $model[$pk];
}
$keys[] = $kk;
}
}
return $keys;
} else {
return array_keys($models);
}
}