我发现您编写的代码有两个问题。第一个是the_title() 重复文章标题，但在这种情况下，返回标题更合适。而且wp_reset_postdata() 应在while 循环内部if 陈述

但正如您所提到的，您只需要帖子标题，就可以直接从查询对象的帖子对象中获取它们，而无需设置循环have_posts() 和the_post(). 就像这样，

add_action(\'woocommerce_after_order_notes\', \'custom_checkout_field\');
function custom_checkout_field($checkout) {

  $args = array(
    \'post_type\'              => \'pickup-point\',
    \'posts_per_page\'         => -1,
    \'post_status\'            => \'publish\',
    \'no_found_rows\'          => true, // pagination not needed
    \'update_post_meta_cache\' => false, // post meta not needed
    \'update_post_term_cache\' => false, // taxonomy terms not needed
  );
  $query = new WP_Query( $args );

  $titles = array_map( \'get_the_title\', $query->posts );
  if ( $titles ) {
    // do something with $titles    
  }

}

主要问题是您需要使用get_the_title() 而不是the_title() 在代码中，作为the_title() 已回显，无法设置为变量。

您似乎希望在WooCommerce结账页面的下拉（或单选按钮）字段中显示您的取货位置（自定义帖子类型）。

您也可以简单地使用get_posts() 功能如下：

add_action(\'woocommerce_after_order_notes\', \'custom_checkout_field\');

function custom_checkout_field( $checkout ) {

    $pickup_points = (array) get_posts( array(
        \'post_type\'         => \'pickup-point\',
        \'posts_per_page\'    => -1,
        \'post_status\'       => \'publish\'
    ) );

    if ( count( $pickup_points ) > 0 ) {

        $available_locations = []; // Initializing

        // Loop though each \'pickup-point\' WP_Post object
        foreach ( $pickup_points as $pickup_point ) {
            // Set current post title in the array
            $available_locations[] = $pickup_point->post_title;
        }

        // testing output
        var_dump ($available_locations);
    }
}

add_action(\'woocommerce_after_order_notes\', \'custom_checkout_field\');

function custom_checkout_field( $checkout ) {

    // Custom query to pull in the pickup points.
    $query = new WP_Query( array(
        \'post_type\'         => \'pickup-point\',
        \'posts_per_page\'    => -1,
        \'post_status\'       => \'publish\'
    ) );

    $available_locations = []; // Initializing

    // Check that we have query results.
    if ( $query->have_posts() ) :

    $available_locations = []; // Initializing

    while ( $query->have_posts() ) : $query->the_post();

    $available_locations[] = get_the_title(); // Set the current title in the array

    endwhile;

    // testing output
    var_dump ($available_locations);

    wp_reset_postdata();

    endif;
}

如果您使用get_posts():

$posts = get_posts(
    array(
        \'post_type\'         => \'pickup-point\',
        \'posts_per_page\'    => -1,
        \'post_status\'       => \'publish\'
    )
);

$titles = array_map( \'get_the_title\', $posts );