Stack Exchange
DepDrop in yii2 not work?
I'm using DepDrop for dependency Dropdownlist. for this, I've written follow codes:
in view form:
use kartik\depdrop\DepDrop;

$catList = ['1' => 1, '2' => 2];
echo $form->field($model, 'cat')->dropDownList($catList, ['id' => 'cat-id']);

// Child # 1
echo $form->field($model, 'subcat')->widget(DepDrop::classname(), [
    'options'       => ['id' => 'subcat-id'],
    'pluginOptions' => [
        'depends'     => ['cat-id'],
        'placeholder' => 'Select...',
        'url'         => \yii\helpers\Url::to(['/faculty/list']),
    ],
]);

Controller:
public function actionList()
{
    $out = [];
    if (isset($_POST['depdrop_parents'])) {
        $parents = $_POST['depdrop_parents'];
        if ($parents != null) {
            $cat_id = $parents[0];
            $out = [
                ['id' => '<sub-cat-id-1>', 'name' => '<sub-cat-name1>'],
                ['id' => '<sub-cat_id_2>', 'name' => '<sub-cat-name2>'],
            ];
            echo Json::encode(['output' => $out, 'selected' => '']);

            return;
        }
    }
    echo Json::encode(['output' => '', 'selected' => '']);
}

but it doesn't work. I found out that actionList is't called by include follow code at the first of actionList function.
file_put_contents("c:/testtest.txt", implode(',',$_POST)); 
and this is head of request:

Request URL: http://admin.same.ir/index.php?r=faculty/list
Request Method: POST
Status Code: 400 Bad Request
Remote Address: 127.0.0.1:80
Referrer Policy: no-referrer-when-downgrade

I don't know what is the problem!!

Probably not related, but "c:/testtest.txt" should be "c:\testtest.txt" because Windows.

No. I've just wanted to say that the function is not called.

it was just for CSRF:
I added follow code to controller:
  public $enableCsrfValidation = false;


you should never turn off the enableCsrfValidation it means you are making your site vulnerable to cross-site scripting
