如何使用自定义菜单选择创建WordPress小部件

我正在为WordPress创建自定义窗口小部件，但希望使用与默认“自定义菜单”窗口小部件相同的选择菜单。到目前为止，除了选择的菜单之外，我的所有工作都没有保存或未在前端显示。任何帮助或指导与此表示赞赏。谢谢。

为简便起见，我删除了额外的小部件选项，因此，基本上，它看起来非常接近“自定义菜单”小部件：

class kedc_mini_sitemap extends WP_Widget {

/*constructor*/
function kedc_mini_sitemap() {
    parent::WP_Widget(false, $name = 'Mini Sitemap');
}

/**/
function widget($args, $instance) {
    extract( $args );

    // widget options
    $title = apply_filters('widget_title', $instance['title']);
    $nav_menu1 = ! empty( $instance['nav_menu'] ) ? wp_get_nav_menu_object( $instance['nav_menu'] ) : false;
    $checkbox = $instance['checkbox'];

    echo $before_widget;    

    if ($title) {
        echo $before_title . $title . $after_title;
    }

    if ($nav_menu1) {
        echo wp_nav_menu( array( 'fallback_cb' => '', 'menu' => $nav_menu1 ) );
    }


    if ($checkbox == true) {
        echo 'This message is displayed if our checkbox is checked.';
    }

    echo $after_widget;
}

/* saves options chosen from the widgets panel */
function update($new_instance, $old_instance) {
    $instance = $old_instance;
    $instance['title'] = strip_tags($new_instance['title']);
    $instance['nav_menu'] = (int) $new_instance['nav_menu'];
    $instance['checkbox'] = strip_tags($new_instance['checkbox']);
    return $instance;
}

/* display widget in widgets panel */
function form($instance) {  

    $title = esc_attr($instance['title']);
    $nav_menu1 = isset( $instance['nav_menu'] ) ? $instance['nav_menu'] : '';
    $checkbox = esc_attr($instance['checkbox']);

    $menus1 = get_terms( 'nav_menu', array( 'hide_empty' => false ) );

    ?>

    <p>
        <label for="<?php echo $this->get_field_id('title'); ?>"><?php _e('Widget Title:'); ?></label>
        <input class="widefat" id="<?php echo $this->get_field_id('title'); ?>" name="<?php echo $this->get_field_name('title'); ?>" type="text" value="<?php echo $title; ?>" />
    </p>

    <p>
        <label for="<?php echo $this->get_field_id('nav_menu'); ?>"><?php _e('Select Menu:'); ?></label>
        <select id="<?php echo $this->get_field_id('nav_menu'); ?>" name="<?php echo $this->get_field_name('nav_menu'); ?>">
            <?php
                foreach ( $menus1 as $menu1 ) {
                    echo '<option value="' . $menu1->term_id . '"'
                        . selected( $nav_menu, $menu1->term_id, false )
                        . '>'. $menu1->name . '</option>';
                }
            ?>
        </select>
    </p>

    <p>
        <input id="<?php echo $this->get_field_id('checkbox'); ?>" name="<?php echo $this->get_field_name('checkbox'); ?>" type="checkbox" value="1" <?php checked( '1', $checkbox ); ?>/>
        <label for="<?php echo $this->get_field_id('checkbox'); ?>"><?php _e('Do you want this to display as 2 columns?'); ?></label>
    </p>

    <?php
}

}

// register widget
add_action('widgets_init', create_function('', 'return register_widget("kedc_mini_sitemap");'));