Embed a Collection of Forms Error: Could not deter

问题:

I am trying to embed collection of Tag forms to Service form, according to this tutorial. Tag and Service entities have many-to-many relationship.

Form is rendering correctly. But when I submit form, I get

Could not determine access type for property "tagList"

error. I don't understand why new Tag object is not added to the Service class by calling the addTag() method.

ServiceType

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder
        ->add('title', TextType::class, array(
            'label' => 'Title'
        ))
    ;

    $builder->add('tagList', CollectionType::class, array(
        'entry_type' => TagType::class,
        'allow_add' => true,
        'allow_delete' => true,
        'by_reference' => false
    )));
}

Service class

{
....
 /**
 * @ORM\ManyToMany(targetEntity="Tag", mappedBy="serviceList",cascade={"persist"})
 */ 
private $tagList;

/**
 * @return ArrayCollection
 */
public function getTagList()
{
    return $this->tagList;
}

/**
 * @param Tag $tag
 * @return Service
 */
public function addTag(Tag $tag)
{
    if ($this->tagList->contains($tag) == false) {
        $this->tagList->add($tag);
        $tag->addService($this);
    }
}

/**
 * @param Tag $tag
 * @return Service
 */
public function removeTag(Tag $tag)
{
    if ($this->tagList->contains($tag)) {
        $this->tagList->removeElement($tag);
        $tag->removeService($this);
    }
    return $this;
}
}

Tag class

 {
  /**
 * @ORM\ManyToMany(targetEntity="Service", inversedBy="tagList")
 * @ORM\JoinTable(name="tags_services")
 */
private $serviceList;
 /**
 * @param Service $service
 * @return Tag
 */
public function addService(Service $service)
{
    if ($this->serviceList->contains($service) == false) {
        $this->serviceList->add($service);
        $service->addTag($this);
    }
    return $this;
}

/**
 * @param Service $service
 * @return Tag
 */
public function removeService(Service $service)
{
    if ($this->serviceList->contains($service)) {
        $this->serviceList->removeElement($service);
        $service->removeTag($this);
    }
    return $this;
}
 }

ServiceController

  public function newAction(Request $request)
{
    $service = new Service();
    $form = $this->createForm('AppBundle\Form\ServiceType', $service);
    $form->handleRequest($request);

    if ($form->isSubmitted() && $form->isValid()) {

        $em = $this->getDoctrine()->getManager();
        $em->persist($service);
        $em->flush();

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

    return $this->render('AppBundle:Service:new.html.twig', array(
        'service' => $service,
        'form' => $form->createView(),
    ));
}

回答1:

Could you please try to implement code from this URL?

http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/association-mapping.html#owning-and-inverse-side-on-a-manytomany-association

First, please try to change mapped/inverse sides, and remove $service->addTag($this); from Tag::addService method.

回答2:

Maybe the problem is that Symfony can't access that property?

If you look at where that exception is thrown (writeProperty method in the PropertyAccessor class) it says it can be thrown:

If the property does not exist or is not public.

In the tutorial you mentioned it has property $tags, and method addTag. I'm just guessing here, but maybe there's a convention where it tries to call a method names add($singularForm) and this is failing for you because the property is tagList and the method is addTag.

I'm not 100% sure, but you could try debugging by setting a stop point in that Symfony method to see why it's being thrown.

回答3:

Short version:

I just ran into this problem and solved it by adding a setter for the affected property:

Could not determine access type for property "tagList"

public function setTagList(Array $tagList)
{
    $this->tagList = $tagList;
}

---

Long version:

The error message is signaling that Symfony is trying to modify the object's state, but cannot figure out how to actually make the change due to the way its class is set up.

Taking a look at Symfony's internals, we can see that Symfony gives you 5 chances to give it access and picks the best one in this order from top to bottom:

1. A setter method named setProperty() with one argument:

This is the first thing Symfony checks for and is the most explicit way to achieve this. As far as I'm aware this is the best practice:

class Entity {

    protected $tagList;

    //...

    public function getTagList()
    {
        return $this->tagList;
    }

    //...
}

2. A combined getter and setter in one method with one argument:

It's important to realize that this method will also be accessed by Symfony in order to get the object's state. Since those method calls don't include an argument, the argument in this method must be optional.

class Entity {

    protected $tagList;

    //...

    public function tagList($tags = null)
    {
        if($reps){
            $this->tagList = $tags;
        } else {
            return $this->tagList;
        }
    }

    //...
}

3. The affected property being declared as public:

   class Entity {
   
       public $tagList;
       //... other properties here
   }
   

4. A __set magic method:

This will affect all properties rather than just the one you intended.

class Entity {

    public $tagList;

    //...

    public function __set($name, $value){
        $this->$name = $value;
    }
    //...
}

5. A __call magic method (in some cases):

I wasn't able to confirm this, but the internal code suggests this is possible when magic is enabled on PropertyAccessor's construction.

---

Only using one of the above strategies is required.

回答4:

Maybe you forgot in the __construct() of Service class and Tag class to initialize $tagList and $serviceList like this ?

$this->tagList = new ArrayCollection();

$this->serviceList = new ArrayCollection();

回答5:

This seems like an error with your constructor. Try this :

public function __construct()
{
    $this-> tagList = new \Doctrine\Common\Collections\ArrayCollection();
}

回答6:

It's a long shot, but looking at your annotations I think the problem might be related to your manyToMany relationship. Try to change the owning side and inverse side (Swap the relationship) unless you specifically need to update from both ends (In that case I think the only solution is to add the objects manually or use oneToMany relationships).

Changes made only to the inverse side of an association are ignored. Make sure to update both sides of a bidirectional association (or at least the owning side, from Doctrine’s point of view)

This is a problem related to Doctrine I have suffered before, see: http://docs.doctrine-project.org/projects/doctrine-orm/en/latest/reference/unitofwork-associations.html

回答7:

Based on Symfony 3.3.10

I actually faced this problem many and many times, finally once i discovered where this problem was coming from, depending on the name you give to your entity property it can happen that the adder and the remover for your collection property aren't exactly what you are expecting.

Example: Your entity properity name is "foo" and you would expect the adder to be called "addFoo" and remover "removeFoo", but then all of a sudden the "Could not determine access type for property" appear.

So you start going into fear searching for w/e problems in your code, instead you just have to look this file inside Symfony core files:

vendor/symfony/symfony/src/Symfony/Component/PropertyAccess/PropertyAccessor.php

Inside this file there's a method called findAdderAndRemover. Go there with your debugger and you will eventually find out that symfony searches for weird name for your adder/remover, they may actually end with "um" or "on" or "us" depending on the language (human language) you used to name them. Since i'm Italian this happen quite often.

Watch out for that, since the fix may be as simple as changing the name used for your add/remove method inside your entity to make them match with what Symfony core is looking for.

This happens to me when i use bin/console doctrine:generate:entities to create the methods automatically for me

回答8:

If you are using symfony, and use EntityRepository instead of CollectionType, make sure you use the 'multiple' => true, on your form build, otherwise the input will be for one entity and not for many, therefore it will call the setTagList instead of using the methods addTagList and removeTagList.