silverstripe-framework/forms/gridfield/GridFieldButtonRow.php

<?php
/**
 * Adding this class to a {@link GridFieldConfig} of a {@link GridField} adds
 * a button row to that field.
 *
 * The button row provides a space for actions on this grid.
 *
 * This row provides two new HTML fragment spaces: 'toolbar-header-left' and
 * 'toolbar-header-right'.
 *
 * @package forms
 * @subpackage fields-gridfield
 */
class GridFieldButtonRow implements GridField_HTMLProvider {

	protected $targetFragment;

	public function __construct($targetFragment = 'before') {
		$this->targetFragment = $targetFragment;
	}

	public function getHTMLFragments( $gridField) {
		$data = new ArrayData(array(
			"TargetFragmentName" => $this->targetFragment,
			"LeftFragment" => "\$DefineFragment(buttons-{$this->targetFragment}-left)",
			"RightFragment" => "\$DefineFragment(buttons-{$this->targetFragment}-right)",
		));

		return array(
			$this->targetFragment => $data->renderWith('Includes/GridFieldButtonRow')
		);
	}
}