I want to make a form with a select field that displays different options.
Those options are a list of `NomenclatureDTO` object field `$libNom` set as:

```php
class NomenclatureDTO
{
    public int $idNom;
    public string $libNom;
    public string $dtMiseEnPlace;
    public string $dtObsolescence;
}

```

Here is the class where the form applies to:

```php
class AvisDTO
{
    public string $dtAvis;
    public string $dtEmission;
    public string $idActeurAuteur;
    public string $nomAuteur;
    public string $prenomAuteur;
    public bool $boEstTacite;
    public ArrayCollection $documents;
    public string $idConsultation;
    public array $idsPieces;
    public int $nomNatureAvisRendu;
    public int $nomTypeAvis;
    public string $txAvis;
    public string $txFondementAvis;
    public string $txHypotheses;
    public string $txQualiteAuteur;

    public function __construct()
    {
        $this->documents = new ArrayCollection();
    }    
}

```

I want to display `libNom` in the select options, but I only need the `idNom` on submit.

So, my form looks like:

```php
<?php

namespace App\Form;

use App\Entity\DTO\AvisDTO;
use App\Entity\DTO\DataFormMapper\DataAvisType;
use App\Entity\DTO\NomenclatureDTO;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\ChoiceList\ChoiceList;
use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
use Symfony\Component\Form\Extension\Core\Type\SubmitType;
use Symfony\Component\Form\Extension\Core\Type\TextareaType;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;

class AvisType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        // dd($options['dataPostAvis']->nomNatureAvisRendu);      L21: SCREENSHOT
        $builder
            ->add('nomAuteur', TextType::class, [
                'label' => "Nom",
            ])
            ->add('prenomAuteur', TextType::class, [
                'label' => "Prénom"
            ])
            ->add('boEstTacite', ChoiceType::class, [
                'required' => true,
                'label' => "L'avis est-il tacite ?",
                'label_attr' => [
                    'class' => "font-weight-bold"
                ],
                'expanded' => true,
                'multiple' => false,
                'choices' => [     
                    'Oui' => true,
                    'Non' => false,                     
                ],                      
            ])          
            ->add('nomNatureAvisRendu', ChoiceType::class, [
                'label' => "Nature de l'avis rendu",
                'required' => false,                
                'choices' => $options['dataPostAvis']->nomNatureAvisRendu,
                'choice_label' => function(?NomenclatureDTO $choice) {                    
                    return $choice->libNom;
                },
                'choice_value' => function(?NomenclatureDTO $choice) {  
                    // dd($choice);                              L50: SCREENSHOT
                    // dd(gettype($choice->idNom), $choice->idNom);L51: SCREENSHOT
                    return $choice->idNom;
                },
            ])
            ->add('nomTypeAvis', ChoiceType::class, [
                'label' => "Type d'avis",
                'required' => false,
                'choices' => $options['dataPostAvis']->nomTypeAvis,
                'choice_label' => function($choice) {                   
                    return $choice->libNom;
                },                              
                'choice_value' => ChoiceList::value($this, 'idNom'),
            ])
            ->add('txAvis', TextareaType::class, [
                'required' => true,
                'attr' => [
                    'placeholder' => "Avis favorable avec prescriptions. \nPremière prescription : Les volets doivent être en bois"
                ]
            ])
            ->add('txFondementAvis', TextareaType::class, [
                'attr' => [
                    'placeholder' => "L'avis de l'ABF est rendu en application de l'article R. 425-30 du Code de l'urbanisme."
                ]
            ])
            ->add('txHypotheses', TextareaType::class, [
                'attr' => [
                    'placeholder' => "Dans l'hypothèse où la puissance électrique nécessaire est de x alors le coût de raccordement est de y"
                ]
            ])
            ->add('txQualiteAuteur', TextareaType::class, [
                'attr' => [
                    'placeholder' => "Qualité"
                ]
            ])

            ->add('Envoyer', SubmitType::class, [
                'row_attr' => [
                    'class' => 'row justify-content-end'
                ],
            ]);
    }

    public function configureOptions(OptionsResolver $resolver): void
    {
        $resolver->setDefaults([
            'data_class' => AvisDTO::class,
            'dataPostAvis' => DataAvisType::class,          
        ]);
    }
}

```

Screenshot L21:

[![Screenshot L21](https://i.stack.imgur.com/KOOWS.png)](https://i.stack.imgur.com/KOOWS.png)

Screenshot L50:

[![Screenshot L50](https://i.stack.imgur.com/O4ogO.png)](https://i.stack.imgur.com/O4ogO.png)

Screenshot L51:

[![Screenshot L51](https://i.stack.imgur.com/cRTxF.png)](https://i.stack.imgur.com/cRTxF.png)

I get this error before the page actually show the form:

> 
> Notice: Trying to get property 'idNom' of non-object
> 
> 
> 

Which makes no sense to me since the dump L51 explicitly says `$choice` is a `NomenclatureDTO` object...

**EDIT**:

I've try to set:

```php
->add('nomNatureAvisRendu', ChoiceType::class, [
    'label' => "Nature de l'avis rendu",
    'required' => false,                
    'choices' => $options['dataPostAvis']->nomNatureAvisRendu,
    'choice_label' => function(?NomenclatureDTO $choice) {                    
        return $choice ? $choice->idNom : null;
    },
    'choice_value' => static function(?NomenclatureDTO $choice): int {  
        return $choice->idNom ?? 0;     
    },
])

```

Which returns on submit:

> 
> Typed property App\Entity\DTO\AvisDTO::$nomNatureAvisRendu must be
> int, App\Entity\DTO\NomenclatureDTO used
> 
> 
>