Default value to 'datetime' field in form loaded from the database

Question

I want to display the datetime field on my Drupal 8 form with some date loaded from the database, but the front end always shows empty fields as if no data has been provided. I tried several combinations to default_value field, but none of them are showing any thing.

The code I am using is the following.

$form['dateopening'] = array(
  '#type' => 'datetime',
  '#title' => t('Opening Date'),
  '#default_value'=> date('Y-m-d H:i:s', strtotime($dateFromDB)),
);

Why doesn't it set the default value as expected?

Answer 1

The response is in this thread : on stackoverflow

$form['valid_dt'] = array(
    '#type' => 'datetime',
    '#default_value' => DrupalDateTime::createFromTimestamp($data->valid_dt),
    '#title' => $this->t('Valid'),      
);