您链接到的代码的主要优点是使用category_template 过滤器，用于修改WordPress在用户查看木材类别的子类别时将使用的模板。我为您整理了这些内容，因为当您只使用一个模板时，它会更简单一些：

// add this filter to your themes functions.php file
add_filter(\'category_template\', \'yourprefix_use_lumber_category_template_for_child_categories\');

function yourprefix_use_lumber_category_template_for_child_categories( $template ) {

    // get the current category object
    $category = get_queried_object();

    // if current category has lumber category(assuming lumber category id == 7) as its parent...
    if( $category->parent == 7 ) {

        // ...then find the named category-lumber.php template in theme, and replace whatever default $template is found by WordPress...
        $template = locate_template(\'category-lumber.php\');

        // ...finally return the lumber category template file
        return $template;

    }
    else {

    // ...the current category has no lumber category as parent, so just return default $template file found by WordPress
    return $template;

    }

}