Wordpress 4.9 / Custom Post Type and Custom Fields

Question

I have made a Custom Post Type called cargo using CPT UI. I have thereafter added several custom fields (port_of_loading, volume, etc) using Advanced Customs field. I have populated the CPT / fields with a few records.

In my template, I have the following code:

$args = array(
    'post_type' => 'cargo',
    'post_per_page' => '12',
);

$cargo = new WP_Query($args);

echo '<pre>';
var_dump($cargo);
echo '</pre>';

if ($cargo->have_posts()) {

    while ( $cargo->have_posts()) : $cargo->the_post() ;
        echo 'Some cargo'.'<.br>';
        get_field('volume');
    endwhile;   
}

Why can't I see the field names in the var_dump from the postmeta table? I can see field value when I echo them though.

Answer 1

WP_Query不知道Advanced Custom字段的键名 ，此类返回WP_Posts数组（Wordpress核心类），Advanced Custom字段是第三方插件。