Some reports need to reflect the filtered records from a search (eg. index view). For these filters, we need to take advantage of the search model.

In the view, add the query param filter to the action parameters:

<?php $curParams = Yii::$app->request->getQueryParams('ProductSearch') ?>
<?= Html::a('<span class="glyphicon glyphicon-print" aria-hidden="true"></span> ' . Yii::t('app', 'Report'), 
    ['report', 'ProductSearch' =>  (!empty($curParams['ProductSearch']) ? $curParams['ProductSearch'] : []) ], 
    ['class' => 'btn btn-default']
) ?>

And in the controller action, query data as follows:

public function actionReport()
{
    $searchModel = new ProductSearch();
    $dataProvider = $searchModel->search(Yii::$app->request->queryParams);
    $dataProvider->sort = ['defaultOrder' => ['vendor'=>SORT_ASC, 'name'=>SORT_ASC]];
 
    // additional query filters
    $dataProvider->query->andWhere(['!=', 'invoice_type', 'CREDIT MEMO']);
    $dataProvider->query->limit(100);
 
    // get data
    $rows = $dataProvider->query->All();
 
    Yii::$app->response->format = yii\web\Response::FORMAT_RAW;  // Raw for PDF output
    return $this->render('report', [
        'data' => $rows,
    ]);
}

See the full example:

<?php
 
use yii\helpers\Html;
use yii\grid\GridView;
 
/* @var $this yii\web\View */
/* @var $searchModel app\models\ComplaintSearch */
/* @var $dataProvider yii\data\ActiveDataProvider */
 
$this->title = Yii::t('app', 'Complaints');
$this->params['breadcrumbs'][] = $this->title;
?>
<div class="complaint-index">
 
    <h1><?= Html::encode($this->title) ?></h1>
    <?php // echo $this->render('_search', ['model' => $searchModel]); ?>
 
    <p>
        <?php //echo '<div class="btn-group">' . 
              //Html::a(Yii::t('app', 'Create Complaint'), ['create'], ['class' => 'btn btn-success']) . 
              //'</div>'; 
        ?>
        <div class="btn-group">
          <?= Html::a('<span class="glyphicon glyphicon-erase" aria-hidden="true"></span> ' . 
              Yii::t('app', 'Reset Search'), ['index'], 
              ['class' => 'btn btn-default']) 
          ?>
        </div>
        &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
        <?php $curParams = Yii::$app->request->getQueryParams('ComplaintSearch') ?>
 
        <!-- Generate Report Options -->
        <div class="btn-group">
            <?= Html::a('<span class="glyphicon glyphicon-print" aria-hidden="true"></span> ' . 
              Yii::t('app', 'Report') . ' <span class="caret">',
                '#', 
                ['class' => 'btn btn-default dropdown-toggle', 
                 'data-toggle'=>"dropdown", 'role'=>"button", 
                 'aria-haspopup'=>"true", 
                 'aria-expanded'=>"false"
                ]) 
            ?>
            <ul class="dropdown-menu">
                <li><?= Html::a(Yii::t('app', 'Report All'),      ['report'], ['class' => '']) ?></li>
                <li><?= Html::a(Yii::t('app', 'Report Selected'), ['report', 
                    'ComplaintSearch' => 
                        (!empty($curParams['ComplaintSearch']) ? $curParams['ComplaintSearch'] : [])
                ], ['class' => '']) ?></li>
            </ul>
        </div>
    </p>
    <?= GridView::widget([
        'dataProvider' => $dataProvider,
        'filterModel' => $searchModel,
        'columns' => [
            ['class' => 'yii\grid\SerialColumn'],
 
            //...
        ],
    ]); ?>
</div>

namespace app\controllers;
 
use Yii;
use app\models\Complaint;
use app\models\ComplaintSearch;
use yii\web\Controller;
use yii\web\Response;
use yii\web\NotFoundHttpException;
use yii\filters\AccessControl;
use yii\filters\VerbFilter;
 
/**
 * ComplaintController implements the CRUD actions for Complaint model.
 */
class ComplaintController extends Controller
{
    //...
 
    public function actionReport($title='')
    {
        date_default_timezone_set('America/New_York');
 
        $searchModel = new ComplaintSearch();
        $dataProvider = $searchModel->search(Yii::$app->request->queryParams);
 
        $rows = $dataProvider->query->All();
 
        Yii::$app->response->format = Response::FORMAT_RAW;  // Raw for PDF output
        return $this->render('report', [
            'data'            => $rows,
            'title'           => $title,
        ]);
    }
}

The data stored in $rows will be filtered, so when we create a report view, it only shows these records.