<?php
/**
 * TDataGrid related class files.
 * This file contains the definition of the following classes:
 * TDataGrid, TDataGridItem, TDataGridItemCollection, TDataGridColumnCollection,
 * TDataGridPagerStyle, TDataGridItemEventParameter,
 * TDataGridCommandEventParameter, TDataGridSortCommandEventParameter,
 * TDataGridPageChangedEventParameter
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @link http://www.pradosoft.com/
 * @copyright Copyright &copy; 2005-2014 PradoSoft
 * @license http://www.pradosoft.com/license/
 * @package Prado\Web\UI\WebControls
 */

namespace Prado\Web\UI\WebControls;

/**
 * TDataGridColumnCollection class.
 *
 * TDataGridColumnCollection represents a collection of data grid columns.
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @package Prado\Web\UI\WebControls
 * @since 3.0
 */
class TDataGridColumnCollection extends TList
{
	/**
	 * the control that owns this collection.
	 * @var TControl
	 */
	private $_o;

	/**
	 * Constructor.
	 * @param TDataGrid the control that owns this collection.
	 */
	public function __construct(TDataGrid $owner)
	{
		$this->_o=$owner;
	}

	/**
	 * @return TDataGrid the control that owns this collection.
	 */
	protected function getOwner()
	{
		return $this->_o;
	}

	/**
	 * Inserts an item at the specified position.
	 * This overrides the parent implementation by inserting only TDataGridColumn.
	 * @param integer the speicified position.
	 * @param mixed new item
	 * @throws TInvalidDataTypeException if the item to be inserted is not a TDataGridColumn.
	 */
	public function insertAt($index,$item)
	{
		if($item instanceof TDataGridColumn)
		{
			$item->setOwner($this->_o);
			parent::insertAt($index,$item);
		}
		else
			throw new TInvalidDataTypeException('datagridcolumncollection_datagridcolumn_required');
	}
}