The form's view data is expected to be an instance of class … but is a(n) string

Question

I am currently receiving the following error:

\"The form\'s view data is expected to be an instance of class Symfony\\Component\\HttpFoundation\\File

Answer 1

Here is the answer:

{
      $builder
          ->add('file', FileType::class, array('data_class' => null))
          ->add('coverFile', FileType::class, array('data_class' => null))
          ->add('coverFile', FileType::class, array('data_class' => null,'required' => false))
          ->add('songName', TextType::class)
          ->add('songAuthor', TextType::class);
  }

Answer 2

/**
 * @ORM\Column(type="string")
 *
 * @Assert\NotBlank(message="Please, upload the song as a MP3 file.")
 * @Assert\File(mimeTypes={ "audio/mpeg", "audio/wav", "audio/x-wav", "application/octet-stream" })
 */
private $file;

You tell doctrine that you want to store a string, but you render an upload button in the form which send you a physic file which you do not want to store in your database at all. Instead you want to move the file from a temporary directory to your upload directory, and you want to remember the name of the file into the database wherefore you need this property which is a string.

Best way is to follow this page