kartik\grid\ExpandRowColumn::renderDataCell PHP Method

    public function renderDataCell($model, $key, $index)
    {
        $options = $this->fetchContentOptions($model, $key, $index);
        $css = 'kv-expand-icon-cell';
        $options['title'] = $this->expandTitle;
        if ($this->value === GridView::ROW_EXPANDED) {
            $options['title'] = $this->collapseTitle;
        }
        if (static::parseData($this->disabled, $model, $key, $index, $this)) {
            $css .= ' kv-state-disabled';
        }
        Html::addCssClass($options, $css);
        $this->initPjax("kvExpandRow({$this->_hashVar});");
        return Html::tag('td', $this->renderDataCellContent($model, $key, $index), $options);
    }