M2 | How to get value of dynamic generated rows values created at system configuration into template?

Question

I have created dynamic rows in configuration, same in SS:

When I save value and check in:

core_config_data

the value it is not what I am saving instead its like

"{"_1556026243400_400":{"productcost":"7"}}"

in the corresponding value column.

This is my system.xml field:

<group id="prices" translate="label" type="text" sortOrder="10" showInDefault="1" showInWebsite="0" showInStore="0">
            <label>Voucher Prices Setting</label>
            <field id="add_item" translate="label" sortOrder="15" showInDefault="1" showInWebsite="1" showInStore="1">
                <label>Dropdown Prices</label>
                <frontend_model>Vendor\Module\Block\Adminhtml\Menu\Field\AdditionalItem</frontend_model>
                <backend_model>Vendor\Module\Block\Adminhtml\Menu\Config\Backend\AdditionalItem</backend_model>
            </field>
</group>

Update:

Here is frontend model:

namespace Vendor\Module\Block\Adminhtml\Menu\Field;

use Magento\Config\Block\System\Config\Form\Field\FieldArray\AbstractFieldArray;

class AdditionalItem extends AbstractFieldArray
{
protected $_typeblockOptions;
protected $_cmsblockOptions;
/**
 * {@inheritdoc}
 */
protected function _prepareToRender()
{

    $this->addColumn(
        'productcost',
        [
            'label' => __('Product Cost'),
            'size' => '200px',
            'class' => 'required-entry'
        ]
    );

    $this->_addAfter = false;
    $this->_addButtonLabel = __('Add');
}
}

Can somebody figure what is missing ? Thanks

Answer 1

You can create helper into your extension at following location to get the value.

app\code\Vendor\Extension\Helper\Data.php

<?php 
namespace Vendor\Extension\Helper;

use Magento\Store\Model\ScopeInterface;

class Data extends \Magento\Framework\App\Helper\AbstractHelper
{
    const PRODUCTCOST = 'pme_giftcard/prices/add_item';

    protected $_storeManager;
    protected $serialize;

    public function __construct(
    \Magento\Framework\App\Helper\Context $context,
    \Magento\Store\Model\StoreManagerInterface $storeManager,
    \Magento\Framework\Serialize\Serializer\Json $serialize)
    {
        $this->_storeManager = $storeManager;
        $this->serialize = $serialize;
        parent::__construct($context);
    }

    public function getStoreid()
    {
        return $this->_storeManager->getStore()->getId();
    }


    public function getProductCost()
    {
        $productcostconfig = $this->scopeConfig->getValue(self::PRODUCTCOST,ScopeInterface::SCOPE_STORE,$this->getStoreid());

        if($productcostconfig == '' || $productcostconfig == null)
            return;

        $unserializedata = $this->serialize->unserialize($productcostconfig);

        $productcostarray = array();
        foreach($unserializedata as $key => $row)
        {
            $productcostarray[] = $row['productcost'];
        }

        return $productcostarray;
    }
}

Now call the helper function getProductCost() to get the value of that field. This return the value into form of array.