title: yii2 checkbox column selected rows - how to get parameters on selected rows using gridview
body: <p>How to get parameters using gridview checkbox on selected rows.
  I have button for multiple action in header of gridview.</p>
  
  <pre><code>Html::button('&lt;i class="glyphicon glyphicon-download-alt"&gt;&lt;/i&gt;', ['type'=&gt;'button', 'title'=&gt;Yii::t('app', 'Bulk Reject'), 'class'=&gt;'btn btn-success', 'onclick'=&gt;'var keys = $("#pjax-list-'.$model-&gt;id.'").yiiGridView("getSelectedRows"); alert(keys ? "Reject " + keys + " selected applicant(s)" : "No rows selected for download");']),
  </code></pre>
  
  <p>I get result number of selected rows. If i select 4 rows. I get below result in alert box.</p>
  
  <pre><code>1,2,3,4
  </code></pre>
  
  <p>I get only keys of selected rows like this 1,2,3,4... in alert box.
  How to get active models data using in gridview. like pk id.</p>
  
  <p>I have method in controller  </p>
  
  <pre><code>public function actionDoreject($userid, $jobid) {
  .....
  }
  </code></pre>
  
  <p>I want to get userid and jobid parameters like this <code>doreject/userid=$model-&gt;userid&amp;jobid=$model-&gt;jobid</code> </p>
  
  <p>I figured out how to get these parameters using javascript.</p>
  
  <p>Further more I added property checkboxOptions like below:</p>
  
  <pre><code>'columns' =&gt; [
          ['class' =&gt; '\kartik\grid\CheckboxColumn', 
          'checkboxOptions' =&gt; function ($model, $key, $index, $column) {
                  return ['data-uid' =&gt; $model-&gt;user_id, 'data-jid'=&gt;$model-&gt;job_id];
              }],
          [
  </code></pre>
  
  <p>view source code of checkbox after using checkboxOptions</p>
  
  <pre><code>&lt;input type="checkbox" name="selection[]" value="1" data-uid="6" data-jid="1"&gt;
  </code></pre>
  
  <p>How to get selected rows data attributes? I get error if I try to get attributes using this code <code>$("#pjax-list-'.$model-&gt;id.'").yiiGridView("getSelectedRows").attr("data-uid")</code></p>
  
  <p>Or is there any simple way to solve this issue?</p>