Components

Creating and using application components

Steps to Create component:

Create a folder named components in your project root folder
Create your component inside components folder e.g.: MyComponent.php

namespace app\components;
    
use Yii;
use yii\base\Component;
use yii\base\InvalidConfigException;
    
    
class MyComponent extends Component
{
    public function demo()
    {
        return "welcome";
    }
}

components' => [
    'mycomponent' => [
        'class' => 'app\components\MyComponent',
    ],
]

Now you can use your component method:

namespace app\controllers;

use Yii;
     
class DemoController extends \yii\web\Controller
{
    public function actionTest()
    {
        echo Yii::$app->mycomponent->demo();
    }
}

Dropdown List using component function

Create function in MyComponent.php

    namespace app\components;

    use Yii;
    use yii\base\Component;
    use yii\base\InvalidConfigException;
    use yii\helpers\Url;
    use yii\helpers\ArrayHelper;
    
    use app\models\User;
    
        class MyComponent extends Component
        {
        
          // Function return list of  id & user Names,used for dropdownlist
          public function getUserID()
          {
            $code = User::find()->select('id,name')
            ->where(['is_deleted'=>'n'])
            ->all();
        
            $result = ArrayHelper::map($code, 'id', 'name');
            if($result)
                return $result;
            else
                return ["null"=>"No User"];
          }
        }

-> Register Component in web.php

components' => [
        'mycomponent' => [
             'class' => 'app\components\MyComponent',
            ],
         ]

-> use it in your view

<?= $form->field($model, 'user_id')->dropDownList(Yii::$app->mycomponent->getUserID())?>