Helpers

HTML::a

// both the same
return Html::a($data->naam, ['/examen/update?id='.$data->id],['title'=> 'Edit',]);
return Html::a($data->naam, ['/examen/update', 'id'=>$data->id], ['title'=> 'Edit',]);

// back
 <?= Html::a( 'Cancel', Yii::$app->request->referrer , ['class'=>'btn btn-primary']); ?>

Array helper

use yii\helpers\ArrayHelper;

$dropdownlist = Arrayhelper::map($student,'id','naam');

//input [ [ 'id' => '999', 'naam' => 'Mark de Groot'], [ 'id' => ..... ], [ ....], ....]
//result [ '999' => 'Mark de Groot', ...];

Link met confirm (gidview Widget)

echo Html::a("<span style=\"color:#800000\" class=\"glyphicon glyphicon-print\"></span>",
   ['print/index', 'id'=>-99],
     [  'title' => 'Print ALL',
        'data' => [
        'confirm' => 'Are you sure you want to print this item?',
        'method' => 'post',
     ],
   ] );

Link met confirm (Html::a)

 echo Html::a("<span class=\"glyphicon glyphicon-trash\"></span>",
	['/print/remove', 'studentid'=>$dataSet[$naam]['studentid'], 'examenid'=>$examenid ],
  	['data-confirm' => 'Delete all results from '.$naam.' from this exam?']);