我已经创建了名为booking的自定义帖子类型。它有一个元booking_first_name, booking_last_name, booking_email, booking_phone, booking_phone_contact. 目前，我成功地显示了电子邮件、电话和手机。

但是，我想将我的帖子标题显示为booking_first_name + booking_last_name. 我怎么能那样做？

以下是我当前的语法：

<?php
/**
 * Register custom admin field
 */
add_filter(\'manage_booking_posts_columns\', \'booking_table_head\');
function booking_table_head( $defaults ) {
    $defaults[\'booking_email\']          = \'Email\';
    $defaults[\'booking_contact_phone\']  = \'Contact Phone\';
    $defaults[\'booking_mobile_phone\']   = \'Mobile Phone\';
    return $defaults;
}

/**
 * Fill custom field value
 */
add_action(\'manage_booking_posts_custom_column\', \'booking_table_content\', 10, 2);
function booking_table_content( $column_name, $post_id ) {

  switch ($column_name) {
    case \'title\':
      $first_name = get_post_meta( $post_id, \'booking_first_name\', true );
      $last_name = get_post_meta( $post_id, \'booking_last_name\', true );
      echo $first_name . \' \' . $last_name;
      break;

    case \'booking_email\':
      $email = get_post_meta( $post_id, \'booking_email\', true );
      echo $email;
      break;

    case \'booking_contact_phone\':
      $contact_phone = get_post_meta( $post_id, \'booking_phone\', true );
      echo $contact_phone;
      break;

    case \'booking_mobile_phone\':
      $mobile_phone = get_post_meta( $post_id, \'booking_phone_mobile\', true );
      echo $mobile_phone;
      break;
  }
}