我找到了一个插件来完成这项工作。

http://wordpress.org/extend/plugins/wp-category-archive/installation/

以下是我刚刚为我的一个客户端构建的小部件的完整代码：

<?php 
/*
 * Archive Widget
 * 
 */

class cb_archive_widget extends WP_Widget {

    /*
     * Register widget with WordPress.
     */
    function cb_archive_widget() {
        parent::WP_Widget(
            false, // Base ID
            \'Custom Archive Widget\', // Name
            array( \'description\' =>  \'Use this widget to place Specific Archives depending on category selection\', ) // Args
        );
    }

    /**
     * Front-end display of widget.
     *
     * @see WP_Widget::widget()
     *
     * @param array $args     Widget arguments.
     * @param array $instance Saved values from database.
     */
    public function widget( $args, $instance ) {
        extract( $args );
        global $cat;
        $cat = $instance[\'arc_cat\'];
        $catID = get_cat_ID( $cat );
        $arc_title = $instance[\'arc_title\'];

        //add the archive filters
        add_filter(\'getarchives_where\',\'ik_custom_archives_where\',10,3);
        add_filter(\'getarchives_join\',\'ik_custom_archives_join\',10,3);

        //add custom SQL to the archives widget JOIN clause
        function ik_custom_archives_join($sql){
            global $wpdb;

            $sql = $sql . "LEFT JOIN $wpdb->term_relationships ON($wpdb->posts.ID = $wpdb->term_relationships.object_id) ";
            $sql = $sql . "LEFT JOIN $wpdb->term_taxonomy ON($wpdb->term_relationships.term_taxonomy_id = $wpdb->term_taxonomy.term_taxonomy_id) ";

            return $sql;
        }

        //add custom SQL to the archives widget WHERE clause
        function ik_custom_archives_where($sql){

            global $wpdb;
            global $cat;
            $catID = get_cat_ID( $cat );

            $sql = "WHERE post_type = \'post\' AND post_status = \'publish\' ";
            $sql = $sql . "AND $wpdb->term_taxonomy.term_id IN ($catID)";

            return $sql;
        }


        $checked = $instance[\'arc_count\'];
        if ($checked == \'on\') { $counter_arc = 1; } else { $counter_arc = 0; };
        $args = array(
                \'show_post_count\' => $counter_arc,
            );
        ?>

        <!-- Display HTML -->
        <?php
        echo $before_widget;
        echo $before_title . $arc_title . $after_title;
        ?>
        <ul>
            <?php wp_get_archives($args); ?>
        </ul>
        <?php 
        echo $after_widget;
    }

    /**
     * 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.
     */
    public function update( $new_instance, $old_instance ) {
        $instance = array();
        $instance = $old_instance;
        $instance[\'arc_title\'] = strip_tags( $new_instance[\'arc_title\'] );
        $instance[\'arc_cat\'] = strip_tags( $new_instance[\'arc_cat\'] );
        $instance[\'arc_count\'] = strip_tags( $new_instance[\'arc_count\'] );
        return $instance;
    }

    /**
     * Back-end widget form.
     *
     * @see WP_Widget::form()
     *
     * @param array $instance Previously saved values from database.
     */
    public function form( $instance ) {
        $arc_title = $instance[\'arc_title\'];
        $arc_checked = $instance[\'arc_count\']; ?>
        <label for="<?php echo $this->get_field_id(\'arc_title\'); ?>"><?php _e( \'Add Title:\' ); ?></label><br/> 
        <input type="text" value="<?php echo attribute_escape($arc_title); ?>" name="<?php echo $this->get_field_name(\'arc_title\'); ?>" id="<?php echo $this->get_field_id(\'arc_title\'); ?>" /><br/>
        <label for="<?php echo $this->get_field_id(\'arc_cat\'); ?>"><?php _e( \'Choose Category:\' ); ?></label><br/> 
        <?php 

            $args = array(
                \'style\'              => \'list\',
                \'show_count\'         => 1,
                \'depth\'              => 1,
                \'taxonomy\'           => \'category\',
                \'walker\'             => null
            );
            $test = get_categories( $args );
            ?>
            <select id="<?php echo $this->get_field_id(\'arc_cat\'); ?>" name="<?php echo $this->get_field_name(\'arc_cat\'); ?>">
            <?php
            foreach( $test as $category) {
                if ($category->category_parent == 0) { ?>
                    <option value="<?php echo $category->name?>" <?php if($category->name == $instance[\'arc_cat\']) echo \' selected="selected"\'; ?>><?php echo $category->name ?></option>
        <?php   }
        }
        ?>
        </select><br/>
        <label for="<?php echo $this->get_field_id(\'arc_count\'); ?>"><?php _e( \'Show Count:\' ); ?></label><br/>
        <input type="checkbox" <?php checked( (bool) $arc_checked, true ); ?> name="<?php echo $this->get_field_name(\'arc_count\'); ?>" id="<?php echo $this->get_field_id(\'arc_count\'); ?>"/>

        <?php 
    }
}// register widget

add_action( \'widgets_init\', create_function(\'\', \'return register_widget("cb_archive_widget");\') );?>

顺便说一句，这仅适用于相关类别，如果您想查看所有类别，只需删除（$category->category\\u parent==0）中的行即可