我正在尝试创建一个有两列的自定义菜单小部件（即，我可以选择两个不同的菜单，并让它们在一个侧边栏小部件中并排显示）。
我找到了一个关于如何创建两列文本小部件的tutorial，但是我不知道如何编辑自定义菜单小部件函数来添加和实现额外的菜单--我试图创建一个额外的菜单变量（如下面的“$menus1”和“$menus2”），这导致WordPress崩溃（“意外的T字符串”错误）。
“$instance”数组是否有一个名为'nav_menu'的预定义键，或者这个键及其值是由“form”函数创建的？如果是后者，我可以定义'nav_menu1'和'nav_menu2'键吗（我以前尝试过，但也得到了“意外的T字符串”错误）？

<?php
/**
 * Custom Menu widget copied from default WP Widget Class and adjusted for 2-columns
 */

class SO_ABC_Tag_List_Widget_2col extends WP_Widget {

    function __construct() {
        $widget_ops = array( 'description' => __('By adding this widget you can select your alphabetical tags menu to display on your website.') );
        parent::__construct( 'so_abc_tags_2col', __('SO ABC Tag List 2 col'), $widget_ops );
    }

    function widget($args, $instance) {
        // Get menu
        $nav_menu1 = ! empty( $instance['nav_menu'] ) ? wp_get_nav_menu_object( $instance['nav_menu'] ) : false;
        $nav_menu2 = ! empty( $instance['nav_menu'] ) ? wp_get_nav_menu_object( $instance['nav_menu'] ) : false;

        if ( !$nav_menu )
            return;

        $instance['title'] = apply_filters( 'widget_title', empty( $instance['title'] ) ? '' : $instance['title'], $instance, $this->id_base );

        echo $args['before_widget'];

        if ( !empty($instance['title']) )
            echo $args['before_title'] . '<i class="icon-tags"></i> ' . $instance['title'] . $args['after_title'];

<div style="float: left; width: 45%">
        wp_nav_menu( array( 'fallback_cb' => '', 'menu' => $nav_menu1 ) );
</div> 

<div style="float: left; width: 45%"></div>     
        wp_nav_menu( array( 'fallback_cb' => '', 'menu' => $nav_menu2 ) );
</div>
        echo $args['after_widget'];
    }

    function update( $new_instance, $old_instance ) {
        $instance['title'] = strip_tags( stripslashes($new_instance['title']) );
        $instance['nav_menu'] = (int) $new_instance['nav_menu'];
        $instance['nav_menu'] = (int) $new_instance['nav_menu'];
        return $instance;
    }

    function form( $instance ) {
        $title = isset( $instance['title'] ) ? $instance['title'] : '';
        $nav_menu1 = isset( $instance['nav_menu'] ) ? $instance['nav_menu'] : '';
        $nav_menu2 = isset( $instance['nav_menu'] ) ? $instance['nav_menu'] : '';

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

        // If no menus exists, direct the user to go and create some.
        if (( !$menus1  ) AND ( !menus2 )) {
            echo '<p>'. sprintf( __('No menus have been created yet. <a href="%s">Create some</a>.'), admin_url('nav-menus.php') ) .'</p>';
            return;
        }
        ?>
        <p>
            <label for="<?php echo $this->get_field_id('title'); ?>"><?php _e('Title:') ?></label>
            <input type="text" class="widefat" id="<?php echo $this->get_field_id('title'); ?>" name="<?php echo $this->get_field_name('title'); ?>" 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>
            <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 ( $menus2 as $menu2 ) {
                echo '<option value="' . $menu2->term_id . '"'
                    . selected( $nav_menu, $menu2->term_id, false )
                    . '>'. $menu2->name . '</option>';
            }
        ?>
            </select>
        </p>
        <?php
    }
}