所以我遇到了this page here 决定再试一次。成功了！

我能够将gallery自定义帖子类型设置为“照片”页面的子页面，该页面是“探索”的子页面，并且在功能中使用此代码，面包屑中的一切都变得完美。php（自定义“案例研究”到我的自定义帖子类型名称）：

//Add the meta box callback function
function admin_init(){
add_meta_box("case_study_parent_id", "Case Study Parent ID", "set_case_study_parent_id", "casestudy", "normal", "low");
}
add_action("admin_init", "admin_init");

//Meta box for setting the parent ID
function set_case_study_parent_id() {
  global $post;
  $custom = get_post_custom($post->ID);
  $parent_id = $custom[\'parent_id\'][0];
  ?>
  <p>Please specify the ID of the page or post to be a parent to this Case Study.</p>
  <p>Leave blank for no heirarchy.  Case studies will appear from the server root with no assocaited parent page or post.</p>
  <input type="text" id="parent_id" name="parent_id" value="<?php echo $post->post_parent; ?>" />
  <?php
  // create a custom nonce for submit verification later
  echo \'<input type="hidden" name="parent_id_noncename" value="\' . wp_create_nonce(__FILE__) . \'" />\';
}

// Save the meta data
function save_case_study_parent_id($post_id) {
  global $post;

  // make sure data came from our meta box
  if (!wp_verify_nonce($_POST[\'parent_id_noncename\'],__FILE__)) return $post_id;
    if(isset($_POST[\'parent_id\']) && ($_POST[\'post_type\'] == "casestudy")) {
      $data = $_POST[\'parent_id\'];
      update_post_meta($post_id, \'parent_id\', $data);
    }
}
add_action("save_post", "save_case_study_parent_id");