yii2_表单下拉菜单

$form->field($model, 'username')->dropDownList(ArrayHelper::map($data,'id', 'customer_name'));

方法2

Html::activeDropDownList($model, 'username', ArrayHelper::map($data,'id', 'customer_name'), ['style' => 'border:1px solid red;']);

方法3

Html::dropDownList('username', null, ArrayHelper::map($data,'id', 'customer_name'), ['class' => 'dropdownlist']);