我认为这篇文章正是你需要的！

WordPress 菜单默认显示为无序列表。不过，您可能希望将它们显示为选择菜单。下面是创建菜单“walker”的示例，该菜单将呈现为选择菜单。当您使用 wp_nav_menu() 显示菜单时，包括 'walker' => new Walker_Nav_Menu_Dropdown() 以告诉 WordPress 使用这种格式而不是默认格式。

函数.php

<?php
// Nav Menu Dropdown Class
include_once( CHILD_DIR . '/lib/classes/nav-menu-dropdown.php' );
/**
 * Mobile Menu
 *
 */
function be_mobile_menu() {
    wp_nav_menu( array(
        'theme_location' => 'mobile',
        'walker'         => new Walker_Nav_Menu_Dropdown(),
        'items_wrap'     => '<div class="mobile-menu"><form><select onchange="if (this.value) window.location.href=this.value">%3$s</select></form></div>',
    ) );    
}
add_action( 'genesis_before_header', 'be_mobile_menu' );

导航菜单dropdown.php

class Walker_Nav_Menu_Dropdown extends Walker_Nav_Menu {
    function start_lvl(&$output, $depth){
        $indent = str_repeat("\t", $depth); // don't output children opening tag (`<ul>`)
    }
    function end_lvl(&$output, $depth){
        $indent = str_repeat("\t", $depth); // don't output children closing tag
    }
    /**
    * Start the element output.
    *
    * @param  string $output Passed by reference. Used to append additional content.
    * @param  object $item   Menu item data object.
    * @param  int $depth     Depth of menu item. May be used for padding.
    * @param  array $args    Additional strings.
    * @return void
    */
    function start_el(&$output, $item, $depth, $args) {
        $url = '#' !== $item->url ? $item->url : '';
        $output .= '<option value="' . $url . '">' . $item->title;
    }   
    function end_el(&$output, $item, $depth){
        $output .= "</option>\n"; // replace closing </li> with the option tag
    }
}

祝你好运！:)