我正在尝试创建一个接受类别的自定义最近帖子小部件，以仅显示该类别中的帖子。我在保存小部件选项时遇到问题。我做了一些调试，发现在更新函数中，$new_instance 仅包含标题选项，不通过\\ u cat。以下是表单和更新的代码：

    /**
     * Back-end widget form.
     *
     * @see WP_Widget::form()
     *
     * @param array $instance Previously saved values from database.
     */
    public function form($instance) {
        /* Set up some default widget settings. */
        $defaults = array( \'title\' => \'\', \'via_cat\' => 1);
        $instance = wp_parse_args( (array) $instance, $defaults );


        $cats = get_terms(\'category\');
        $category_data = array();
        foreach ($cats as $cat) {
            $category_data[$cat->term_id] = $cat->name;
        }
?>
<p>
    <label for="<?php echo $this->get_field_id( \'title\' ); ?>"><?php _e( \'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 esc_attr( $instance[\'title\'] ); ?>" />
</p>
<p>
    <label for="<?php echo $this->get_field_id(\'via_cat\'); ?>"><?php _e( \'Category:\' ); ?></label>
    <select id="<?php echo $this->get_field_id(\'via_cat\'); ?>" name="<?php echo $this->get_field_id(\'via_cat\'); ?>">
<?php
        foreach ($category_data as $id => $name) {
?>
        <option value="<?php echo $id; ?>"<?php echo $instance[\'via_cat\'] == $id ? \' selected="selected"\' : \'\'; ?>><?php echo $name; ?></option>
<?php
        }
?>
    </select>
</p>
<?php
    }



/**
 * Sanitize widget form values as they are saved.
 *
 * @see WP_Widget::update()
 *
 * @param array $new_instance Values just sent to be saved.
 * @param array $old_instance Previously saved values from database.
 *
 * @return array Updated safe values to be saved.
 */
function update( $new_instance, $old_instance ) {
    $instance = $old_instance;
    $instance[\'title\'] = strip_tags( $new_instance[\'title\'] );
    $instance[\'via_cat\'] = $new_instance[\'via_cat\'];

    return $instance;
}