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