假设只有两个级别的类别，可以先检索父类别，然后列出子类别。此外，呼叫get_children 和wp_list_categories 使用的资源比需要的多，仅使用wp_list_categories 就足够了。我已经在下面的代码片段中解释了我的答案，它的行为应该完全符合您的需要！

$category_id = get_query_var( \'cat\' ); // Get current catgory ID
$category = get_term( $category_id, \'category\' ); // Fetch category term object

// Now, we check if the category has a parent
// If it has, we use that ID
// If it doesn\'t have a parent, it is a parent category itself and we use its own ID
$parent = $category->parent ? $category->parent : $category_id;

$args = array(
    \'show_count\' => false,
    \'hide_empty\' => false,
    \'title_li\' => \'\',
    \'show_option_none\' => \'\',
    \'echo\' => false
);

// Show the children of parent category
if ( $category->parent ) {
    $args[\'child_of\'] = $category->parent;
    $args[\'exclude\'] = $category_id; // Don\'t display the current category in this list
}
else {
    $args[\'child_of\'] = $category_id;
}

// Get the category list
$categories_list = wp_list_categories( $args );

if ( $categories_list ) {
    ?>
    <div class="category-wrapper">
        <ul class="child-categories">
            <?php echo $categories_list; ?>
        </ul>
    </div>
    <?php
}