public function __construct(DataGrid $datagrid, $item, $primary_key)
{
$this->control = Html::el('tr');
$this->datagrid = $datagrid;
$this->item = $item;
$this->primary_key = $primary_key;
$this->id = $this->getValue($primary_key);
if ($datagrid->hasColumnsSummary()) {
$datagrid->getColumnsSummary()->add($this);
}
}