Hello I have created admin grid for my custom module, I have a form where it is possible to add new product comments. The thing is that I have Product id field, where u can enter id for which product to post comment. So if non-existent id is entered and saved the page breaks.

This is my save controller:

<?php   namespace Vendor\Module\Controller\Adminhtml\Comments;  use Magento\Backend\App\Action; use Magebit\ProductComments\Model\Comments; use Magento\Catalog\Api\ProductRepositoryInterface;  class Save extends Action {       private $  productRepository;     protected $  _model;      /**      * @param Action\Context $  context      */     public function __construct(         Action\Context $  context,         Comments $  model,         ProductRepositoryInterface $  productRepository     ) {         parent::__construct($  context);         $  this->_model = $  model;         $  this->productRepository = $  productRepository;     }      /**      * {@inheritdoc}      */       /**      * Save action      *      * @return \Magento\Framework\Controller\ResultInterface      */     public function execute()     {         $  data = $  this->getRequest()->getPostValue();         /** @var \Magento\Backend\Model\View\Result\Redirect $  resultRedirect */         $  resultRedirect = $  this->resultRedirectFactory->create();         if ($  data) {             /** @var \Vendor\Module\Model\Comments $  model */             $  model = $  this->_model;              $  id = $  this->getRequest()->getParam('id');             if ($  id) {                 $  model->load($  id);             }              $  model->setData($  data);              $  this->_eventManager->dispatch(                 'productcomments_comments_prepare_save',                 ['comments' => $  model, 'request' => $  this->getRequest()]             );              try {                 $  model->save();                 $  this->messageManager->addSuccess(__('Comment successfully saved'));                 $  this->_getSession()->setFormData(false);                 if ($  this->getRequest()->getParam('back')) {                     return $  resultRedirect->setPath('*/*/edit', ['id' => $  model->getId(), '_current' => true]);                 }                 return $  resultRedirect->setPath('*/*/');             } 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, __('Something went wrong while saving the comment'));             }              $  this->_getSession()->setFormData($  data);             return $  resultRedirect->setPath('*/*/edit', ['comment_id' => $  this->getRequest()->getParam('id')]);         }         return $  resultRedirect->setPath('*/*/');     } } 

I was thinking about using productrepository getByID function, but haven’t yet figured it out. Hope someone will have answers for me, thanks!