Magento 2 ui multi-select preselected values

Question

I am new at Magento 2,

UI multi-select component render store views group by websites and stores,

but when I am editing I need saved values of store views of certain record to be preselected in that multi-select.

class StoreViews extends \Magento\Cms\Ui\Component\Listing\Column\Cms\Options
{
    /**
     * @var SegmentFactory $segment
     */
    protected $segmentFactory;

    /**
     * @var Segment $segmentModel
     */
    protected $segmentModel;

    /**
     * @var  Http $reguest
     */
    protected $request;


    public function __construct(SystemStore $systemStore, Escaper $escaper, SegmentFactory $segmentFactory, Http $request, Segment $segmentModel)
    {
        parent::__construct($systemStore, $escaper);
        $this->segmentFactory = $segmentFactory;
        $this->segmentModel = $segmentModel;
        $this->request = $request;
    }

    public function toOptionArray()
    {
        $id = $this->request->getParams()['segment_id'];

        $model = $this->segmentModel;
        $segmentFactory = $this->segmentFactory->create();
        $segmentFactory->load($model, $id, 'segment_id');

        $currentValues = json_decode($model->getData()['store_views']);

        return $options;
    }

}

FORM

 <field name="store_views">
            <argument name="data" xsi:type="array">
                <item name="options" xsi:type="object">CodePool\CustomModule\Ui\Component\Form\StoreViews</item>
                <item name="config" xsi:type="array">
                    <item name="dataType" xsi:type="string">int</item>
                    <item name="label" xsi:type="string" translate="true">Store View</item>
                    <item name="formElement" xsi:type="string">multiselect</item>
                    <item name="source" xsi:type="string">page</item>
                    <item name="dataScope" xsi:type="string">store_views</item>
                    <item name="default" xsi:type="string">0</item>
                </item>
            </argument>
        </field>

---

Answer 1

try:

<item name="default" xsi:type="string">1,2,3</item>

or with form:

     $fieldset->addField(
                'countries',
                'multiselect',
                [
                    'name' => 'countries',
                    'label' => __('Select countries'),
                    'id' => 'countries',
                    'values' => $allCountries,
                    'class' => 'status',
                ]
            );
 $model->setData("countries", [1,2,3]); // value in $allCountries not lable