Yii2 dropdownList选择默认选项

Question

我在网址中通过GET返回cat_id值来表示我的下拉列表,必须选择哪个项目.但它不起作用.

<?= $form->field($model, 'cat_id')->dropDownList(
ArrayHelper::map(DeviceCats::find()
->where(['is_deleted' => 'no'])->all(),'id','title')
,['options' => [$_GET['cat_id'] => ['selected'=>true]]
, 'prompt' => ' -- Select Category --']) ?>

Answer 1

终于解决了令人难以置信的变化.刚刚将所选的第一个字母更改为大写(' selected '应该是' Selected ').这是代码:

<?= $form->field($model, 'cat_id')->dropDownList(
ArrayHelper::map(DeviceCats::find()
->where(['is_deleted' => 'no'])->all(),'id','title')
,['options' => [$_GET['cat_id'] => ['Selected'=>'selected']]
, 'prompt' => ' -- Select Category --']) ?>

Answer 2

'Selected'必须用大写字母'S'写成:

'options'=>['72'=>['Selected'=>true]]