GridFieldConfig_BlockManager::__construct PHP Method

    public function __construct($canAdd = true, $canEdit = true, $canDelete = true, $editableRows = false, $aboveOrBelow = false)
    {
        parent::__construct();
        $this->blockManager = Injector::inst()->get('BlockManager');
        $controllerClass = Controller::curr()->class;
        // Get available Areas (for page) or all in case of ModelAdmin
        if ($controllerClass == 'CMSPageEditController') {
            $currentPage = Controller::curr()->currentPage();
            $areasFieldSource = $this->blockManager->getAreasForPageType($currentPage->ClassName);
        } else {
            $areasFieldSource = $this->blockManager->getAreasForTheme();
        }
        // EditableColumns only makes sense on Saveable parenst (eg Page), or inline changes won't be saved
        if ($editableRows) {
            $this->addComponent($editable = new GridFieldEditableColumns());
            $displayfields = array('TypeForGridfield' => array('title' => _t('Block.BlockType', 'Block Type'), 'field' => 'LiteralField'), 'Title' => array('title' => _t('Block.Title', 'Title'), 'field' => 'ReadonlyField'), 'BlockArea' => array('title' => _t('Block.BlockArea', 'Block Area') . '
						            ', 'callback' => function () use($areasFieldSource) {
                $areasField = DropdownField::create('BlockArea', 'Block Area', $areasFieldSource);
                if (count($areasFieldSource) > 1) {
                    $areasField->setHasEmptyDefault(true);
                }
                return $areasField;
            }), 'isPublishedIcon' => array('title' => _t('Block.IsPublishedField', 'Published'), 'field' => 'LiteralField'), 'UsageListAsString' => array('title' => _t('Block.UsageListAsString', 'Used on'), 'field' => 'LiteralField'));
            if ($aboveOrBelow) {
                $displayfields['AboveOrBelow'] = array('title' => _t('GridFieldConfigBlockManager.AboveOrBelow', 'Above or Below'), 'callback' => function () {
                    return DropdownField::create('AboveOrBelow', _t('GridFieldConfigBlockManager.AboveOrBelow', 'Above or Below'), BlockSet::config()->get('above_or_below_options'));
                });
            }
            $editable->setDisplayFields($displayfields);
        } else {
            $this->addComponent($dcols = new GridFieldDataColumns());
            $displayfields = array('TypeForGridfield' => array('title' => _t('Block.BlockType', 'Block Type'), 'field' => 'LiteralField'), 'Title' => _t('Block.Title', 'Title'), 'BlockArea' => _t('Block.BlockArea', 'Block Area'), 'isPublishedIcon' => array('title' => _t('Block.IsPublishedField', 'Published'), 'field' => 'LiteralField'), 'UsageListAsString' => _t('Block.UsageListAsString', 'Used on'));
            $dcols->setDisplayFields($displayfields);
            $dcols->setFieldCasting(array('UsageListAsString' => 'HTMLText->Raw'));
        }
        $this->addComponent(new GridFieldButtonRow('before'));
        $this->addComponent(new GridFieldToolbarHeader());
        $this->addComponent(new GridFieldDetailForm());
        $this->addComponent($sort = new GridFieldSortableHeader());
        $this->addComponent($filter = new GridFieldFilterHeader());
        $this->addComponent(new GridFieldDetailForm());
        if ($controllerClass == 'BlockAdmin' && class_exists('GridFieldCopyButton')) {
            $this->addComponent(new GridFieldCopyButton());
        }
        $filter->setThrowExceptionOnBadDataType(false);
        $sort->setThrowExceptionOnBadDataType(false);
        if ($canAdd) {
            $multiClass = new GridFieldAddNewMultiClass();
            $classes = $this->blockManager->getBlockClasses();
            $multiClass->setClasses($classes);
            $this->addComponent($multiClass);
            //$this->addComponent(new GridFieldAddNewButton());
        }
        if ($canEdit) {
            $this->addComponent(new GridFieldEditButton());
        }
        if ($canDelete) {
            $this->addComponent(new GridFieldDeleteAction(true));
        }
        return $this;
    }