public function addActionCallback($key, $name, $callback = null)
	{
		$this->addActionCheck($key);

		$params = ['__id' => $this->primary_key];

		$this->actions[$key] = $action = new Column\ActionCallback($this, $key, $name, $params);

		if ($callback) {
			if (!is_callable($callback)) {
				throw new DataGridException('ActionCallback callback has to be callable.');
			}

			$action->onClick[] = $callback;
		}

		return $action;
	}