在 Drupal 8 中提交时如何创建多个同名字段并获取其值？

Question

下面是我在 Drupal 8 中自定义模块的配置表单。

<?php
 namespance Drupal\hello_world\Form;

 class MailForm extends ConfigFormBase {

   public function buildForm(array $form, FormStateInterface $form_state) {

     $form = parent::buildForm($form, $form_state);

     $form['email_address'] = [
       '#type' => 'email',
       '#title' => $this->t(
         'Email address:'
       ),
     ];

     return $form;
   }

   public function submitForm(array &$form, FormStateInterface $form_state) {

     $email_address = $form_state->getValue('email_address');

   }
 }

如何在 Drupal 8 中创建多个同名的输入字段？

<input name="email_address[]" type="email" />
<input name="email_address[]" type="email"  />
<input name="email_address[]" type="email" />

在 Drupal 8 中提交时，如何从上述输入字段中获取所有值，如下所示？

array(
  'email_address' => array(
    '0' => 'a@email.com',
    '1' => 'b@email.com',
    '2' => 'c@email.com',
  )
)

Answer 1

创建两级数组并使用'#tree' => TRUE 选项：

$form['email_address'] = [
  '#type' => 'fieldset',
  '#tree' => TRUE,
  '#title' => $this->t('Email address:'),
  '0' => [
    '#type' => 'email',
    '#title' => $this->t('First'),
  ],
  '1' => [
    '#type' => 'email',
    '#title' => $this->t('First'),
  ],
];

我唯一不能完全确定的（因为我没有检查过这段代码）是电子邮件元素的数字索引。如果它有效，请发表评论。如果没有 - 使用字符串。