yii2_study10_关联数据库的下拉列表

1.修改backend\views\branches_form.php

use yii\helpers\ArrayHelper;
use backend\models\Companies;

    <?= $form->field($model, 'companies_company_id')->dropDownList(
    ArrayHelper::map(Companies::find()->all(),'company_name','company_id'),
    ['prompt'=>'Select Company']
    )?>

2.访问 http://https://https://amyflash.com/yii/advanced/backend/web/index.php?r=branches%2Fcreate ,发现下拉列表中自动关联了company_name