How to load existing data in "Dynamic Rows" in product edit form

To achieve this you need to follow the steps to create

You need etc/adminhtml/di.xml add following.

<virtualType name="Magento\Catalog\Ui\DataProvider\Product\Form\Modifier\Pool"> <arguments> <argument name="modifiers" xsi:type="array"> <item name="advanced-supplier-pricing" xsi:type="array"> <item name="class" xsi:type="string">Vendor\Supplier\Ui\DataProvider\Product\Form\Modifier\AdvancedSupplierPrices</item> <item name="sortOrder" xsi:type="number">20</item> </item> </argument> </arguments> </virtualType> 

Create AdvancedSupplierPrices.php

namespace Vendor\Supplier\Ui\DataProvider\Product\Form\Modifier; use Magento\Catalog\Model\Locator\LocatorInterface; use Magento\Catalog\Ui\DataProvider\Product\Form\Modifier\AbstractModifier; use Magento\Ui\Component\Form\Element\DataType\Price; use Magento\Ui\Component\Form\Fieldset; use Magento\Ui\Component\Form\Field; use Magento\Ui\Component\Form\Element\Input; use Magento\Ui\Component\DynamicRows; use Magento\Ui\Component\Container; use Magento\Ui\Component\Form\Element\Select; use Magento\Ui\Component\Form\Element\DataType\Text; class AdvancedSupplierPrices extends AbstractModifier { const FIELD_IS_DELETE = 'is_delete'; const FIELD_SORT_ORDER_NAME = 'sort_order'; /** * @var LocatorInterface */ private $locator; public function __construct( LocatorInterface $locator ) { $this->locator = $locator; } public function modifyData(array $data) { $fieldCode = 'supplier_fieldset'; $model = $this->locator->getProduct(); $modelId = $model->getId(); $data[$modelId]['product'][$fieldCode]['supplier_field'] = [ [ 'record_id' => 0, 'supplier' => 'supplier1', 'cost_price' => '22', 'sell_price' => '44', ], [ 'record_id' => 1, 'supplier' => 'supplier2', 'cost_price' => '222', 'sell_price' => '444', ] ]; return $data; } public function modifyMeta(array $meta) { $meta = array_replace_recursive( $meta, [ 'supplier_fieldset' => [ 'arguments' => [ 'data' => [ 'config' => [ 'label' => __('Supplier'), 'componentType' => Fieldset::NAME, 'dataScope' => 'data.product.supplier_fieldset', 'collapsible' => true, 'sortOrder' => 5, ], ], ], 'children' => [ "supplier_field" => $this->getSelectTypeGridConfig(10) ], ] ] ); return $meta; } protected function getSelectTypeGridConfig($sortOrder) { return [ 'arguments' => [ 'data' => [ 'config' => [ 'addButtonLabel' => __('Add Supplier'), 'componentType' => DynamicRows::NAME, 'component' => 'Magento_Ui/js/dynamic-rows/dynamic-rows', 'additionalClasses' => 'admin__field-wide', 'deleteProperty' => static::FIELD_IS_DELETE, 'deleteValue' => '1', 'renderDefaultRecord' => false, 'sortOrder' => $sortOrder, ], ], ], 'children' => [ 'record' => [ 'arguments' => [ 'data' => [ 'config' => [ 'componentType' => Container::NAME, 'component' => 'Magento_Ui/js/dynamic-rows/record', 'positionProvider' => static::FIELD_SORT_ORDER_NAME, 'isTemplate' => true, 'is_collection' => true, ], ], ], 'children' => [ 'supplier' => [ 'arguments' => [ 'data' => [ 'config' => [ 'formElement' => Select::NAME, 'componentType' => Field::NAME, 'dataType' => Text::NAME, 'dataScope' => 'supplier', 'label' => __('Supplier Name'), 'options' => [ [ 'label' => __('supplier1'), 'value'=> 'supplier1' ], [ 'label' => __('supplier2'), 'value'=> 'supplier2' ] ], 'value' => 0, 'sortOrder' => 20, ], ], ], ], 'cost_price' => [ 'arguments' => [ 'data' => [ 'config' => [ 'componentType' => Field::NAME, 'formElement' => Input::NAME, 'dataType' => Price::NAME, 'label' => __('Cost Price'), 'enableLabel' => true, 'dataScope' => 'cost_price', 'sortOrder' => 40, 'validation' => [ 'required-entry' => true, 'validate-greater-than-zero' => true, 'validate-number' => true, ], ], ], ], ], 'sell_price' => [ 'arguments' => [ 'data' => [ 'config' => [ 'componentType' => Field::NAME, 'formElement' => Input::NAME, 'dataType' => Price::NAME, 'label' => __('Sell Price'), 'enableLabel' => true, 'dataScope' => 'sell_price', 'sortOrder' => 40, 'validation' => [ 'required-entry' => true, 'validate-greater-than-zero' => true, 'validate-number' => true, ], ], ], ], ], 'actionDelete' => [ 'arguments' => [ 'data' => [ 'config' => [ 'componentType' => 'actionDelete', 'dataType' => Text::NAME, 'label' => '', 'sortOrder' => 50, ], ], ], ], ] ] ] ]; } }