Yii2 activeDropDownList fundamentals -

i'm new yii2 not mvc (trying move focus ms yii2). i've scaffolded app db using gii. have table called track have table called music_category. there's n:n relationship via link table called track_has_music_category. track model (as scaffolded gii) has function

 public function getmusiccategories() {     return $this->hasmany(musiccategory::classname(), ['id' => 'music_category_id'])->viatable('track_has_music_category', ['track_id' => 'id']); } 

but retrieving categories have been 'link'ed track. guess need like

<?= html::activedropdownlist(thecategorymodel (syntax here??), 'id', arrayhelper::map(thecategorymodel->findall(),'id', ''description)) ?> 

well, that. feel though online reference few worked examples.

any appreciated.

cheers mark

let's want attach categories track model ($model):

echo html::activecheckboxlist($model, 'musiccategories', arrayhelper::map(musiccategory::findall(),'id', ''description)) 

we use activecheckboxlist here since it's multiple relation. although need add $model logic save these relations. have @ how work many-to-many relations in yii2