Symfony错误（“可捕获的致命错误：Proxies__CG __ \\ AppBundle \\ Entity \\ Type类的对象无法转换为字符串”）

Question

I want the Game entity to appear with the related Type. It's a many-to-one relation for the Game and a one-to-many for the Type entity. So a Game can have 1 Type while a Type can have many Games.

I get the error:

An exception has been thrown during the rendering of a template ("Catchable Fatal Error: Object of class Proxies__CG__\\AppBundle\\Entity\\Type could not be converted to string").

When scrolling down it points to line 14 of the views/game/show.html.twig file:

<tr>
    <th>Type</th>
    <td>{{ game.type}}</td>
</tr>

The question: how do I show the current Game's Type in the view?

Here's my code:

GameController.php:

<?php

namespace AppBundle\Controller;

use AppBundle\Entity\Game;
use AppBundle\Entity\Type;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Method;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
use Symfony\Component\HttpFoundation\Request;

/**
 * Game controller.
 *
 * @Route("game")
 */
class GameController extends Controller
{
    /**
     * Lists all game entities.
     *
     * @Route("/", name="game_index")
     * @Method("GET")
     */
    public function indexAction()
    {
        $em = $this->getDoctrine()->getManager();

        $games = $em->getRepository('AppBundle:Game')->findAll();

        return $this->render('game/index.html.twig', array(
            'games' => $games,
        ));
    }

    /**
     * Creates a new game entity.
     *
     * @Route("/new", name="game_new")
     * @Method({"GET", "POST"})
     */
    public function newAction(Request $request)
    {

        $game = new Game();

        $form = $this->createForm('AppBundle\Form\GameType', $game);
        $form->handleRequest($request);

        if ($form->isSubmitted() && $form->isValid()) {
            $em = $this->getDoctrine()->getManager();
            $em->persist($game);
            $em->flush($game);

            return $this->redirectToRoute('game_show', array('id' => $game->getId()));
        }

        return $this->render('game/new.html.twig', array(
            'game' => $game,
            'form' => $form->createView(),
        ));
    }

    /**
     * Finds and displays a game entity.
     *
     * @Route("/{id}", name="game_show")
     * @Method("GET")
     * @inheritdoc
     *
     */
    public function showAction(Game $game, Type $type)
    {
        $deleteForm = $this->createDeleteForm($game);


        return $this->render('game/show.html.twig', array(
            'game' => $game,
            'type' => $game->getType(),
            'delete_form' => $deleteForm->createView(),
        ));
    }

    /**
     * Displays a form to edit an existing game entity.
     *
     * @Route("/{id}/edit", name="game_edit")
     * @Method({"GET", "POST"})
     */
    public function editAction(Request $request, Game $game)
    {
        $deleteForm = $this->createDeleteForm($game);
        $editForm = $this->createForm('AppBundle\Form\GameType', $game);
        $editForm->handleRequest($request);

        if ($editForm->isSubmitted() && $editForm->isValid()) {
            $this->getDoctrine()->getManager()->flush();

            return $this->redirectToRoute('game_show', array('id' => $game->getId()));
        }

        return $this->render('game/edit.html.twig', array(
            'game' => $game,
            'edit_form' => $editForm->createView(),
            'delete_form' => $deleteForm->createView(),

        ));
    }

    /**
     * Deletes a game entity.
     *
     * @Route("/{id}", name="game_delete")
     * @Method("DELETE")
     */
    public function deleteAction(Request $request, Game $game)
    {
        $form = $this->createDeleteForm($game);
        $form->handleRequest($request);

        if ($form->isSubmitted() && $form->isValid()) {
            $em = $this->getDoctrine()->getManager();
            $em->remove($game);
            $em->flush($game);
        }

        return $this->redirectToRoute('game_index');
    }

    /**
     * Creates a form to delete a game entity.
     *
     * @param Game $game The game entity
     *
     * @return \Symfony\Component\Form\Form The form
     */
    private function createDeleteForm(Game $game)
    {
        return $this->createFormBuilder()
            ->setAction($this->generateUrl('game_delete', array('id' => $game->getId())))
            ->setMethod('DELETE')
            ->getForm()
        ;
    }
}

TypeController.php

<?php

namespace AppBundle\Controller;

use AppBundle\Entity\Type;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Method;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;use Symfony\Component\HttpFoundation\Request;

/**
 * Type controller.
 *
 * @Route("type")
 */
class TypeController extends Controller
{
    /**
     * Lists all type entities.
     *
     * @Route("/", name="type_index")
     * @Method("GET")
     */
    public function indexAction()
    {
        $em = $this->getDoctrine()->getManager();

        $types = $em->getRepository('AppBundle:Type')->findAll();

        return $this->render('type/index.html.twig', array(
            'types' => $types,
        ));
    }

    /**
     * Creates a new type entity.
     *
     * @Route("/new", name="type_new")
     * @Method({"GET", "POST"})
     */
    public function newAction(Request $request)
    {
        $type = new Type();
        $form = $this->createForm('AppBundle\Form\TypeType', $type);
        $form->handleRequest($request);

        if ($form->isSubmitted() && $form->isValid()) {
            $em = $this->getDoctrine()->getManager();
            $em->persist($type);
            $em->flush($type);

            return $this->redirectToRoute('type_show', array('id' => $type->getId()));
        }

        return $this->render('type/new.html.twig', array(
            'type' => $type,
            'form' => $form->createView(),
        ));
    }

    /**
     * Finds and displays a type entity.
     *
     * @Route("/{id}", name="type_show")
     * @Method("GET")
     */
    public function showAction(Type $type)
    {
        $deleteForm = $this->createDeleteForm($type);

        return $this->render('type/show.html.twig', array(
            'type' => $type,
            'delete_form' => $deleteForm->createView(),
        ));
    }

    /**
     * Displays a form to edit an existing type entity.
     *
     * @Route("/{id}/edit", name="type_edit")
     * @Method({"GET", "POST"})
     */
    public function editAction(Request $request, Type $type)
    {
        $deleteForm = $this->createDeleteForm($type);
        $editForm = $this->createForm('AppBundle\Form\TypeType', $type);
        $editForm->handleRequest($request);

        if ($editForm->isSubmitted() && $editForm->isValid()) {
            $this->getDoctrine()->getManager()->flush();

            return $this->redirectToRoute('type_edit', array('id' => $type->getId()));
        }

        return $this->render('type/edit.html.twig', array(
            'type' => $type,
            'edit_form' => $editForm->createView(),
            'delete_form' => $deleteForm->createView(),
        ));
    }

    /**
     * Deletes a type entity.
     *
     * @Route("/{id}", name="type_delete")
     * @Method("DELETE")
     */
    public function deleteAction(Request $request, Type $type)
    {
        $form = $this->createDeleteForm($type);
        $form->handleRequest($request);

        if ($form->isSubmitted() && $form->isValid()) {
            $em = $this->getDoctrine()->getManager();
            $em->remove($type);
            $em->flush($type);
        }

        return $this->redirectToRoute('type_index');
    }

    /**
     * Creates a form to delete a type entity.
     *
     * @param Type $type The type entity
     *
     * @return \Symfony\Component\Form\Form The form
     */
    private function createDeleteForm(Type $type)
    {
        return $this->createFormBuilder()
            ->setAction($this->generateUrl('type_delete', array('id' => $type->getId())))
            ->setMethod('DELETE')
            ->getForm()
        ;
    }
}

Game.php

<?php

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;
use Doctrine\Common\Collections\ArrayCollection;
use Symfony\Component\Validator\Constraints as Assert;
/**
 * Game
 *
 * @ORM\Table(name="game")
 * @ORM\Entity(repositoryClass="AppBundle\Repository\GameRepository")
 */
class Game
{
    /**
     * @ORM\ManyToOne(targetEntity="Type", inversedBy="games")
     * @ORM\JoinColumn(name="type_id", referencedColumnName="id")
     */
    private $type;



    /**
     * @var int
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;


    /**
     * @var string
     * @Assert\NotBlank()
     * @Assert\Length(
     *     min = "3",
     *  max = "100"
     * )
     * @ORM\Column(name="name", type="string", length=255, unique=true)
     */
    private $name;


    /**
     * Get id
     *
     * @return int
     */
    public function getId()
    {
        return $this->id;
    }

    /**
     * Set name
     *
     * @param string $name
     *
     * @return Game
     */
    public function setName($name)
    {
        $this->name = $name;

        return $this;
    }

    /**
     * Get name
     *
     * @return string
     */
    public function getName()
    {
        return $this->name;
    }

    /**
     * @return mixed
     */
    public function getType()
    {
        return $this->type;
    }

    /**
     * @param mixed $type
     */
    public function setType($type)
    {
        $this->type = $type;
    }
}

Type.php

<?php

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;
use Doctrine\Common\Collections\ArrayCollection;


/**
 * Type
 *
 * @ORM\Table(name="type")
 * @ORM\Entity(repositoryClass="AppBundle\Repository\TypeRepository")
 */
class Type
{
    /**
     * @ORM\OneToMany(targetEntity="Game", mappedBy="type")
     */
    private $games;

    public function __construct()
    {
        $this->games = new ArrayCollection();
    }
    /**
     * @var int
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
     * @var string
     *
     * @ORM\Column(name="name", type="string", length=255)
     */
    private $name;




    /**
     * Get id
     *
     * @return int
     */
    public function getId()
    {
        return $this->id;
    }

    /**
     * Set name
     *
     * @param string $name
     *
     * @return Type
     */
    public function setName($name)
    {
        $this->name = $name;

        return $this;
    }

    /**
     * Get name
     *
     * @return string
     */
    public function getName()
    {
        return $this->name;
    }

    /**
     * @return mixed
     */
    public function getGames()
    {
        return $this->games;
    }

    /**
     * @param mixed $games
     */
    public function setGames($games)
    {
        $this->games = $games;
    }

    public function addGame(Game $game)
    {
        $this->games->add($game);
        $game->setType($this);
    }
    public function removeGame(Game $game)
    {
        $this->games->removeElement($game);
    }
}

GameType.php

<?php

namespace AppBundle\Form;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Bridge\Doctrine\Form\Type\EntityType;
use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;

class GameType extends AbstractType
{
    /**
     * {@inheritdoc}
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add( 'name', TextType::class, [
                'attr'  => [
                    'class' => 'form-control',
                ],
            ] );
        $builder
            ->add( 'type', EntityType::class, [
                'class' => 'AppBundle:Type',
                'choice_label' => 'name',
                'multiple' => false,
                'expanded' => false,
                'attr'  => [
                    'class' => 'form-control',
                ],

            ] );


    }

    /**
     * {@inheritdoc}
     */
    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => 'AppBundle\Entity\Game'
        ));
    }

    /**
     * {@inheritdoc}
     */
    public function getBlockPrefix()
    {
        return 'appbundle_game';
    }


}

TypeType.php

<?php

namespace AppBundle\Form;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;

class TypeType extends AbstractType
{
    /**
     * {@inheritdoc}
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('name')        ;
    }

    /**
     * {@inheritdoc}
     */
    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => 'AppBundle\Entity\Type'
        ));
    }

    /**
     * {@inheritdoc}
     */
    public function getBlockPrefix()
    {
        return 'appbundle_type';
    }
}

Answer 1

You need a bit of work in your GameType.php form:

// GameType.php
$builder
    ->add('type', EntityType::class, [
        'class' => 'AppBundle:Type',
        'placeholder' => ' ',
        'choice_label' => function($type){
            return $type->getName();
        },
        'multiple' => false, // a user can select only one option per submission
        'expanded' => false // options will be presented in a <select> element; set this to true, to present the data as checkboxes
    ])
;

Then, in the game/show.html.twig template:

{{ game.type.name }} //supposing you want to display the name column of the types table

Tip: Each time you are facing this kind of trouble, you can use {{ dump(variable) }} to check what's inside it.

For a full ManyToOne example check this article.