今天在做一款企业主题，想实现上面这种 调用出当前父分类下的所有子分类

下面是代码，放在functions.php中：

function get_category_root_id($cat) {
  // 取得当前分类
  $this_category = get_category($cat);
  // 若当前分类有上级分类时循环
  while($this_category->category_parent) {
  // 将当前分类设为上级分类
$this_category = get_category($this_category->category_parent); 
}
  // 返回根分类的id号
  return $this_category->term_id; 
}

下面是调用代码，列出所有子分类

<?php wp_list_categories('child_of='.get_category_root_id($cat).'&depth=1&hide_empty=0&hierarchical=1&optioncount=1&title_li=');?>

但是并不能调用当前的父分类名和链接，网上找了半天教程结果只有调用出当前的子分类，并不包括父分类，开始测试了用调用当前分类的调用代码来实现，但是点击子分类的时候，父分类就不显示了

最后自己想了个办法，当点击子分类的时候怎么显示当前父分类呢？代码如下：

<a href="<?php echo get_category_link(get_category_root_id($cat));?>"><?php echo get_cat_name(get_category_root_id($cat));?></a>

这个代码实现方法也很简单。

看了其他主题的代码，实现效果是下面这样的，但是我使用不知道什么原因，调用不出，而且代码太复杂了。所以也弃用了。

<?php if ( is_page() ) { ?>
    <?php
                $parent_page = $post->ID;
                while($parent_page) {
                    $page_query = $wpdb->get_row("SELECT ID, post_title, post_status, post_parent FROM $wpdb->posts WHERE ID = '$parent_page'");
                    $parent_page = $page_query->post_parent;
                 }
               $parent_id = $page_query->ID;
               $parent_title = $page_query->post_title;
                if ($wpdb->get_results("SELECT * FROM $wpdb->posts WHERE post_parent = '$parent_id' AND post_status != 'attachment'")) { ?>
    <?php $subpage = wp_list_pages('depth=1&echo=0&child_of='.$parent_id); ?>
    <?php //key ?>
    <?php if($subpage) { ?>
      <div class="page-menu-title"><h3><?php echo $parent_title; ?></h3></div>

        <?php wp_list_pages('depth=1&sort_column=menu_order&title_li=&child_of='. $parent_id); ?>
    <?php } else { ?>
	<div class="page-menu-title"><h3><?php echo $parent_title; ?></h3></div>
	<li class=""><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
	<?php } ?>
    <?php } ?>
    <!-- SubPageList end -->
    <?php } elseif( is_search() || is_404() ) { ?>
    <?php } else { ?>
    <?php
				$this_category = get_the_category();
				$category_id = $this_category[0]->cat_ID;
				$parent_id = get_category_root_id( $category_id );
				$category_link = get_category_link( $parent_id );
        		$childcat = get_categories('child_of='.$parent_id);
				if( $childcat && $parent_id ){
			?>
    <!-- SubCatList begin -->
       <div class="page-menu-title"><h3><a href="<?php echo get_category_link( $parent_id ); ?>" title=" <?php echo get_cat_name( $parent_id ); ?>" style="color: #FFF;"><?php echo get_cat_name( $parent_id ); ?></a></h3></div>

        <?php wp_list_cats("orderby=id&child_of=" . $parent_id . "&depth=2&hide_empty=0"); ?>
    <!-- SubCatList end -->
    <?php } else { ?>
	<div class="page-menu-title"><h3><?php $category = get_the_category(); echo $category[0]->cat_name; ?></h3></div>
    <li class=""><?php the_category(', ') ?></li>
	<?php } ?>
    <?php } ?>
    <?php wp_reset_query(); ?>
                    </ul>
                </div>
            </section>
        </section><section class="page-menu">
                <div class="page-menu-content">
                    <ul>
                        <?php if ( is_page() ) { ?>
                            <!-- SubPageList begin -->
                            <?php
                            $parent_page = $post->ID;
                            while($parent_page) {
                                $page_query = $wpdb->get_row("SELECT ID, post_title, post_status, post_parent FROM $wpdb->posts WHERE ID = '$parent_page'");
                                $parent_page = $page_query->post_parent;
                            }
                            $parent_id = $page_query->ID;
                            $parent_title = $page_query->post_title;
                            if ($wpdb->get_results("SELECT * FROM $wpdb->posts WHERE post_parent = '$parent_id' AND post_status != 'attachment'")) { ?>
                                <?php $subpage = wp_list_pages('depth=1&echo=0&child_of='.$parent_id); ?>
                                <?php //key ?>
                                <?php if($subpage) { ?>
                                  <div class="page-menu-title"><h3><?php echo $parent_title; ?></h3></div>

                                  <?php wp_list_pages('depth=1&sort_column=menu_order&title_li=&child_of='. $parent_id); ?>
                              <?php } else { ?>
                               <div class="page-menu-title"><h3><?php echo $parent_title; ?></h3></div>
                               <li class=""><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
                           <?php } ?>
                       <?php } ?>
                       <!-- SubPageList end -->
                   <?php } elseif( is_search() || is_404() ) { ?>
                   <?php } else { ?>
                    <?php
                    $this_category = get_the_category();
                    $category_id = $this_category[0]->cat_ID;
                    $parent_id = get_category_root_id( $category_id );
                    $category_link = get_category_link( $parent_id );
                    $childcat = get_categories('child_of='.$parent_id);
                    if( $childcat && $parent_id ){
                     ?>
                     <!-- SubCatList begin -->
                     <div class="page-menu-title"><h3><a href="<?php echo get_category_link( $parent_id ); ?>" title=" <?php echo get_cat_name( $parent_id ); ?>" style="color: #FFF;"><?php echo get_cat_name( $parent_id ); ?></a></h3></div>

                     <?php wp_list_cats("orderby=id&child_of=" . $parent_id . "&depth=2&hide_empty=0"); ?>
                     <!-- SubCatList end -->
                 <?php } else { ?>
                   <div class="page-menu-title"><h3><?php $category = get_the_category(); echo $category[0]->cat_name; ?></h3></div>
                   <li class=""><?php the_category(', ') ?></li>
               <?php } ?>
           <?php } ?>
           <?php wp_reset_query(); ?>
       </ul>
   </div>
</section><?php if ( is_page() ) { ?>
    <?php
                $parent_page = $post->ID;
                while($parent_page) {
                    $page_query = $wpdb->get_row("SELECT ID, post_title, post_status, post_parent FROM $wpdb->posts WHERE ID = '$parent_page'");
                    $parent_page = $page_query->post_parent;
                 }
               $parent_id = $page_query->ID;
               $parent_title = $page_query->post_title;
                if ($wpdb->get_results("SELECT * FROM $wpdb->posts WHERE post_parent = '$parent_id' AND post_status != 'attachment'")) { ?>
    <?php $subpage = wp_list_pages('depth=1&echo=0&child_of='.$parent_id); ?>
    <?php //key ?>
    <?php if($subpage) { ?>
      <div class="page-menu-title"><h3><?php echo $parent_title; ?></h3></div>

        <?php wp_list_pages('depth=1&sort_column=menu_order&title_li=&child_of='. $parent_id); ?>
    <?php } else { ?>
	<div class="page-menu-title"><h3><?php echo $parent_title; ?></h3></div>
	<li class=""><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></li>
	<?php } ?>
    <?php } ?>
    <!-- SubPageList end -->
    <?php } elseif( is_search() || is_404() ) { ?>
    <?php } else { ?>
    <?php
				$this_category = get_the_category();
				$category_id = $this_category[0]->cat_ID;
				$parent_id = get_category_root_id( $category_id );
				$category_link = get_category_link( $parent_id );
        		$childcat = get_categories('child_of='.$parent_id);
				if( $childcat && $parent_id ){
			?>
    <!-- SubCatList begin -->
       <div class="page-menu-title"><h3><a href="<?php echo get_category_link( $parent_id ); ?>" title=" <?php echo get_cat_name( $parent_id ); ?>" style="color: #FFF;"><?php echo get_cat_name( $parent_id ); ?></a></h3></div>

        <?php wp_list_cats("orderby=id&child_of=" . $parent_id . "&depth=2&hide_empty=0"); ?>
    <!-- SubCatList end -->
    <?php } else { ?>
	<div class="page-menu-title"><h3><?php $category = get_the_category(); echo $category[0]->cat_name; ?></h3></div>
    <li class=""><?php the_category(', ') ?></li>
	<?php } ?>
    <?php } ?>
    <?php wp_reset_query(); ?>
                    </ul>
                </div>
            </section>
        </section>