在wordpress中显示所有帖子元键和相同帖子ID的元值

我正在尝试显示发布元值和发布元键，如果只显示一个值，我可以使用简单的函数get_post_meta()，但是我现在需要的是发布所有具有相同post_id的发布元数据.我尝试使用foreach循环，但没有任何显示.你能检查一下我的密码吗?

I'm trying to display post meta values and post meta keys, If only one value is to be display I can used the simple function get_post_meta() but what I need now is to post all post meta data with the same post_id. I tried using foreach loop but nothing displays. can you please check my codes?

function wpt_calendar_display()
{
    global $post;

    $columns = array(
        'date_event' => 'Date',
        'name_event' => 'Event'
    );
    register_column_headers('list-header_events', $columns);

    $event_name = get_post_meta( $post->ID, '_event_name' );
   // $event_date = get_post_meta( $post->ID, '_event_date', false );

    $return .= "<table class=\"widefat\">";
    $return .= "<tr>";
    $return .= print_column_headers('list-header_events');
    $return .= "</tr>";
    $return .= "<tr>";

    if (!empty($event_name))
    foreach($event_name as $e_name)
    {
        $return .= "<td>";
        $return .= $e_name;
        $return .="</td>";

    }

    $return .= "<td>";

    $return .= "</td>";
    $return .= "</tr>";
    $return .= "</table>";
    return $return;
}