Magento 2.1:- Issue in Save Form with multiselect value

Question

I create one admin form with multiselect form. Check below my code.

$objectManager = \Magento\Framework\App\ObjectManager::getInstance();
$carrierOptions = $objectManager->get('\Magento\Shipping\Model\Config\Source\Allmethods')->toOptionArray();
$groupOptions = $objectManager->get('\Magento\Customer\Model\ResourceModel\Group\Collection')->toOptionArray();

        $fieldset->addField(
            'carriers',
            'multiselect',
            [
                'name'     => 'carriers[]',
                'label'    => __('Shipping Carriers'),
                'title' => __('Shipping Carriers'),
                'required' => true,
                'values' => $carrierOptions,
                'disabled' => $isElementDisabled,
            ]
        );

        $fieldset->addField(
            'customer_group',
            'multiselect',
            [
                'name'     => 'customer_group[]',
                'label'    => __('Customer Groups'),
                'title' => __('Customer Group'),
                'values' => $groupOptions,
                'disabled' => $isElementDisabled,
            ]
        );

My Save Action like this.

<?php

namespace Vendor\ShippingTest\Controller\Adminhtml\Index;

use Magento\Backend\App\Action;
use Vendor\ShippingTest\Model\ShippingTestFactory;

class Save extends \Magento\Backend\App\Action
{
    protected $ShippingTestFactory;

    public function __construct(Action\Context $context , ShippingTestFactory $ShippingTestFactory)
    {
        $this->ShippingTestFactory = $ShippingTestFactory;
        parent::__construct($context);
    }

    protected function _isAllowed()
    {
        return $this->_authorization->isAllowed('Vendor_ShippingTest::shippingtest_save');
    }

    public function execute()
    {
        $data = $this->getRequest()->getPostValue();
        $resultRedirect = $this->resultRedirectFactory->create();

        if ($data) {
            $model = $this->ShippingTestFactory->create();
            $model->setData($data)
                ->setId($this->getRequest()->getParam('id'));

            try {

                $model->save();

                $this->messageManager->addSuccess(__('ShippingTest was successfully saved'));
                $this->_objectManager->get('Magento\Backend\Model\Session')->setFormData(false);

                if ($this->getRequest()->getParam('back')) {
                    return $resultRedirect->setPath('*/*/edit', ['id' => $model->getId(), '_current' => true]);
                }
                $this->_redirect('*/*/');
                return;

            } catch (\Magento\Framework\Exception\LocalizedException $e) {
                $this->messageManager->addError($e->getMessage());
            } catch (\RuntimeException $e) {
                $this->messageManager->addError($e->getMessage());
            } catch (\Exception $e) {
                $this->messageManager->addException($e, __($e->getMessage().'Something went wrong while saving the page.'));
            }

            $this->_getSession()->setFormData($data);
            return $resultRedirect->setPath('*/*/edit', ['id' => $this->getRequest()->getParam('id')]);
        }

        return $resultRedirect->setPath('*/*/');
    }   
}

Now when i save this form i got error like this. Notice: Array to string conversion in /vendor/magento/framework/DB/Adapter/Pdo/Mysql.php on line 2915Something went wrong while saving the page. Give me proper suggestion.

Answer 1

Hello I got solution for my above question. I put two line in save action, before $model->setData($data)

$data['carriers']=implode(',',$data['carriers']);
$data['customer_group']=implode(',',$data['customer_group']);
$model->setData($data)
      ->setId($this->getRequest()->getParam('id'));

Now, no any error found and i saved this data in database.