如何让Symfony为实体中的可空字段呈现复选框？

Let’s say I have a nullable datetime field in my entity:

class Foo
{
    /**
     * @ORM\Column(name="due", type="datetime", nullable=true)
     */
    private $due;

    public function getDue()
    {
        return $this->due;
    }

    public function setDue($due)
    {
        $this->due = $due;
        return $this;
    }
}

And now in the FooType.php I define a form field for this:

public function buildForm(FormBuilderInterface $builder, array $options)
{
    $builder
        // ...
        ->add('due', 'datetime')
        // ...
    ;
}

However, even though the field is nullable, the form field rendered will allow the user only to enter a date/time, but not to say that it should be null.

I would like to have either a radio button UI like this:

( ) No due date
( ) Due date:   [ control ]

or perhaps a checkbox:

[ ] Due date:   [ control ]

Ideally, if “no due date” is selected/the checkbox is unchecked, the control should be disabled.

Is it possible to do this elegantly in Symfony?

Afaik theres no symfony provided solution

i would

$builder
    // ...
    ->add('due', 'hidden')

and in view you implement the logic with html and js

so two checkboxes on click on due-date you show a datetime input then

you just need to set the value (null || thedatetimeinputvalue) to the hidden field before submit