Display only top level categories.

Hi,

I am trying to display only the top level of categories, on a category page. to be clearer, when a category is selected in the menu, it shows only the child posts of that category, and not the grandchildren.

Have been puzzling over this for a few days know. but must be missing something basic. This is the code for my category page. Any help much appreciated. Thanks.

<?php get_header(); ?>

<div id=”content”>
<h1><?php printf( __( ‘%s’ ), ‘<span>’ . single_cat_title( ”, false ) . ‘</span>’ ); ?></h1>
<?php echo category_description(); /* displays the category’s description from the WordPress admin */ ?>

<div class=”cat-grid”>
<?php
if (have_posts()) : while (have_posts()) : the_post();

// The following determines what the post format is and shows the correct file accordingly
$format = get_post_format();
get_template_part( ‘includes/post-formats/’.$format );

if($format == ”)
get_template_part( ‘includes/post-formats/standard’ );

?>

<?php endwhile; else: ?>

<div class=”no-results”>
<?php echo ‘<p>‘ . __(‘There has been an error.’, ‘theme1774’) . ‘</p>’; ?>
<p><?php _e(‘We apologize for any inconvenience, please’, ‘theme1774’); ?> /” title=”<?php bloginfo(‘description’); ?>”><?php _e(‘return to the home page’, ‘theme1774’); ?> <?php _e(‘or use the search form below.’, ‘theme1774’); ?></p>
<?php get_search_form(); /* outputs the default WordPress search form */ ?>
</div><!–no-results–>

<?php endif; ?>
</div>
<?php get_template_part(‘includes/post-formats/post-nav’); ?>

</div><!–#content–>

<?php get_footer(); ?>