PHP错误调用数组上的成员函数format（）

Question

I have a date time field

    /**
 * @var \DateTime
 *
 * @ORM\Column(name="date", type="datetime", nullable=true)
 */
private $datetime;  

/**
 * Set date
 *
 * @param \DateTime $datetime
 *
 */
public function setDate($datetime)
{
    $this->datetime = $datetime;

    return $this->datetime ?? new \DateTime();
}

/**
 * Get date
 *
 * @return \DateTime
 */
public function getDate(): \DateTime
{
    return $this->datetime ?? new \DateTime();
}

I this error below:

Call to a member function format() on array

Anyone know why I get this?

Edit:

Below is the code that I use to generate a form to read in the DateTime value and then collect the data from the form and create a new entity in the table:

$trainingform = new Training();

    $form = $this->createFormBuilder($trainingform)
        ->add('Leader', TextType::class)
        ->add('Date', DateTimeType::class, ['label' => 'Date and Time'])
        ->add('topics', TextType::class, ['label' => 'Topics Being Covered'])
        ->getForm();

    if ($form->handleRequest($request)->isValid()) {
        $trainingform->setLeader($request->request->get('form')['Leader']); 
        $trainingform->setDate($request->request->get('form')['Date']);
        $trainingform->setTopics($request->request->get('form')['topics']);
        $em->persist($trainingform);
        $em->flush();
    }

Answer 1

To handle your data correctly you should use symfony form's getData-method, which will transform your request to the state you've specified in your form before. In your case it should look like this:

    $trainingForm = new Training();

    $form = $this->createFormBuilder($trainingForm)
        ->add('Leader', TextType::class) // 'Leader' should be named as your property
        ->add('datetime', DateTimeType::class, ['label' => 'Date and Time']) //changed your Date to datetime as your property is
        ->add('topics', TextType::class, ['label' => 'Topics Being Covered'])  //should be named as your property as well
        ->add('submit', SubmitType::class, ['label' => 'Submit form']) //should be there
        ->getForm();

    $form->handleRequest($request)

    if (form->isSubmitted() && form->isValid()) {
        $trainingForm= $form->getData();
        $em->persist($trainingForm);
        $em->flush();
    }

To avoid such inconsistency, you could specify the required type on your setter method:

/**
 * Set date
 *
 * @param \DateTime $datetime
 */
public function setDate(\DateTime $datetime) //typhint added
{
    $this->datetime = $datetime;
}

`

Setter shouldn't return anything btw. Then you would get your error on the step you can control and you would know where you should dig after.