为自己保存一个循环get_posts 和\'fields\' => \'ids\'.

// Default Query

function do_query($args = null) {
    $default_args = array( 
        \'numberposts\' => -1,
        \'posts_per_page\' => -1,
        \'post_status\' => \'publish\',
        \'fields\' => \'ids\',
    );

    if (null !== $args && !empty($args))
        $args = array_merge($default_args, $args);
    else 
        $args = $default_args;

    return get_posts($args);
}

// Customize Query

$post_ids = do_query ( 
    array(
        \'post_type\' => \'products\',
        \'meta_key\' => \'price\',
        \'orderby\' => \'meta_value_num\',
        \'order\' => \'ASC\',
));

// Search for the index of the ID / prev / next

$currentID = get_the_ID(); 
$currentINX = array_search( $currentID, $post_ids);

$count = count($post_ids);

$prevINX = $currentINX - 1;
if ( $prevINX < 0 ) $prevID = FALSE;
else $prevID = $post_ids [ $prevINX ];

$nextINX = $currentINX + 1;
if ( $nextINX >= $count ) $nextINX = FALSE;
else $nextID = $post_ids [ $nextINX ];

// Output links

if ( $prevID ) {
    $link = get_permalink ( $prevID );
    echo "<a href=\\"${link}\\">previous product</a>";
}

if ( $nextID ) {
    $link = get_permalink ( $nextID );
    echo "<a href=\\"${link}\\">next product</a>";
}

使用自定义查询后，需要调用wp_reset_postdata() 函数，在使用以下函数之前重置全局post数据get_the_ID()

<?php
// Setting up the loop
$args = array(
\'post_type\' => \'products\', 
\'post_status\' => \'publish\',
\'meta_key\' => \'price\',
\'orderby\' => \'meta_value_num\',
\'order\' => \'ASC\',
\'posts_per_page\' => -1
);
$posts_query = new WP_Query($args);

// Setting up the array in which ALL IDs of all product posts will be stored
$posts = array();

// Starting the loop
while ($posts_query->have_posts()) {
    // Including the post IDs one by one    
    $posts[] += $post->ID;
}

wp_reset_postdata(); //reset the global post data



$current = array_search(get_the_ID(), $posts);
$prevID = $posts[$current-1];
$nextID = $posts[$current+1];

if (!empty($prevID)) { ?>
<a href="www.example.com/post_type=products&post_id=<?php 
echo $prevID; ?>">previous product</a>
<?php }
if (!empty($nextID)) { ?>
<a href="www.example.com/post_type=products&post_id=<?php 
echo $nextID; ?>">next product</a>
<?php } ?>