Symfony Form ManyToOne OneToMany

Question

I have three entities, Block, BlockPlacement, BlockPosition:

class BlockEntity
{
    private $bid;
    /**
     * @ORM\OneToMany(
     *     targetEntity="BlockPlacementEntity",
     *     mappedBy="block",
     *     cascade={"remove"})
     */
    private $placements;
}

class BlockPlacementEntity
{
    /**
     * The id of the block postion
     *
     * @ORM\Id
     * @ORM\ManyToOne(targetEntity="BlockPositionEntity", inversedBy="placements")
     * @ORM\JoinColumn(name="pid", referencedColumnName="pid", nullable=false)
     */
    private $position;

    /**
     * The id of the block
     *
     * @var BlockEntity
     * @ORM\Id
     * @ORM\ManyToOne(targetEntity="BlockEntity", inversedBy="placements")
     * @ORM\JoinColumn(name="bid", referencedColumnName="bid", nullable=false)
     */
    private $block;

    private $sortorder;
}

class BlockPositionEntity
{
    private $pid;
    /**
     * @ORM\OneToMany(
     *     targetEntity="BlockPlacementEntity",
     *     mappedBy="position",
     *     cascade={"remove"})
     * @ORM\OrderBy({"sortorder" = "ASC"})
     */
    private $placements;
}

---

So, you can see the relationship: Block < OneToMany > Placement < ManyToOne > Position.

Now I am trying to construct a form to create/edit a block:

    $builder
        ->add($builder->create('placements', 'entity', [
            'class' => 'Zikula\BlocksModule\Entity\BlockPositionEntity',
            'choice_label' => 'name',
            'multiple' => true,
            'required' => false
        ]))
    ;

This gives me a good select box with multiple selections possible with a proper list of positions to choose from. But it does not show previous selections for placement (I am using existing data) e.g. marking positions as 'selected'. I have not tried creating a new Block yet, only editing existing data.

I suspect I will need to be using addModelTransformer() or addViewTransformer() but have tried some of this an cannot get it to work.

I've looked at the collection form type and I don't like that solution because it isn't a multi-select box. It requires JS and isn't as intuitive as a simple select element.

This seems like such a common issue for people. I've searched and found no common answer and nothing that helps.

Answer 1

OK - so in the end, I found a different way. @Stepan Yudin's answer worked, but is complicated (listeners, etc) and not quite like I was hoping.

So, I have the same three entities. BlockPlacement and BlockPosition remain the same (and so aren't reposted, see above) but I have made some changes to the BlockEntity:

class BlockEntity
{
    private $bid;
    /**
     * @ORM\OneToMany(
     *     targetEntity="BlockPlacementEntity",
     *     mappedBy="block",
     *     cascade={"remove", "persist"},
     *     orphanRemoval=true)
     */
    private $placements;

    /**
     * Get an ArrayCollection of BlockPositionEntity that are assigned to this Block
     * @return ArrayCollection
     */
    public function getPositions()
    {
        $positions = new ArrayCollection();
        foreach($this->getPlacements() as $placement) {
            $positions->add($placement->getPosition());
        }

        return $positions;
    }

    /**
     * Set BlockPlacementsEntity from provided ArrayCollection of positionEntity
     * requires
     *   cascade={"remove, "persist"}
     *   orphanRemoval=true
     *   on the association of $this->placements
     * @param ArrayCollection $positions
     */
    public function setPositions(ArrayCollection $positions)
    {
        // remove placements and skip existing placements.
        foreach ($this->placements as $placement) {
            if (!$positions->contains($placement->getPosition())) {
                $this->placements->removeElement($placement);
            } else {
                $positions->removeElement($placement->getPosition()); // remove from positions to add.
            }
        }

        // add new placements
        foreach ($positions as $position) {
            $placement = new BlockPlacementEntity();
            $placement->setPosition($position);
            // sortorder is irrelevant at this stage.
            $placement->setBlock($this); // auto-adds placement
        }
    }
}

So you can see that the BlockEntity is now handling a positions parameter which doesn't exist in the entity at all. Here is the relevant form component:

$builder
    ->add('positions', 'Symfony\Bridge\Doctrine\Form\Type\EntityType', [
        'class' => 'Zikula\BlocksModule\Entity\BlockPositionEntity',
        'choice_label' => 'name',
        'multiple' => true,
    ])

note that I have changed to Symfony 2.8 form style since my first post

This renders a multiple select element on the page which accepts any number of positions and converts them to an ArrayCollection on submit. This is then handled directly by the form's get/set position methods and these convert to/from the placement property. The cascade and orphanRemoval are important because they take care to 'clean up' the leftover entities.

because it is references above here is the BlockPlacement setBlock($block) method:

public function setBlock(BlockEntity $block = null)
{
    if ($this->block !== null) {
        $this->block->removePlacement($this);
    }

    if ($block !== null) {
        $block->addPlacement($this);
    }

    $this->block = $block;

    return $this;
}