wordpress plugin - How do you add custom columns for these custom post types? -

i've been developing plugin involves custom post types , taxonomies. i'm struggling @ moment getting custom post fields display in 'all reservations' screen. can columns display, cannot life of me fields within columns populate data database.

my custom post code below:

    function reservations_init() {       $labels = array(         'name'               => _x( 'reservations', 'post type general name' ),         'singular_name'      => _x( 'reservation', 'post type singular name' ),         'add_new'            => _x( 'add new', 'reservation' ),         'add_new_item'       => __( 'add new reservation' ),         'edit_item'          => __( 'edit reservation' ),         'new_item'           => __( 'new reservation' ),         'all_items'          => __( 'reservations' ),         'view_item'          => __( 'view reservation' ),         'search_items'       => __( 'search reservations' ),         'not_found'          => __( 'no reservations found' ),         'not_found_in_trash' => __( 'no reservations found in trash' ),          'parent_item_colon'  => '',         'menu_name'          => 'reservations'       );       $args = array(         'labels'        => $labels,         'description'   => 'holds our reservations',         'public'        => true,         'menu_position' => 5,         'supports'      => array( 'none' ),         'has_archive'   => true,         'show_in_nav_menu' => true,         'show_in_menu' => 'edit.php?post_type=meals',       );       register_post_type( 'reservations', $args );     }     add_action( 'init', 'reservations_init' );        function restauranter_add_meta_box() {            $screens = array( 'reservations' );            foreach ( $screens $screen ) {                add_meta_box(                   'restauranter_firstname',                   __( 'reservation details', 'restauranter' ),                   'restauranter_reservation_details',                   $screen,                    'normal',                    'high'               );           }       }       add_action( 'add_meta_boxes', 'restauranter_add_meta_box' );        function restauranter_reservation_details() {           global $post;            echo '<input type="hidden" name="reservationmeta_noncename" id="reservationmeta_noncename" value="' .            wp_create_nonce( plugin_basename(__file__) ) . '" />';            $firstname = get_post_meta($post->id, '_firstname', true);           $lastname = get_post_meta($post->id, '_lastname', true);           $phone = get_post_meta($post->id, '_phone', true);           $email = get_post_meta($post->id, '_email', true);           $guests = get_post_meta($post->id, '_guests', true);           $date = get_post_meta($post->id, '_date', true);           $time = get_post_meta($post->id, '_time', true);          echo '<p>first name:</p>';         echo '<input type="text" name="_firstname" value="' . $firstname  . '" class="widefat" />';         echo '<p>last name:</p>';         echo '<input type="text" name="_lastname" value="' . $lastname  . '" class="widefat" />';         echo '<p>phone number:</p>';         echo '<input type="text" name="_phone" value="' . $phone  . '" class="widefat" />';         echo '<p>email:</p>';         echo '<input type="text" name="_email" value="' . $email  . '" class="widefat" />';         echo '<p>number of guests:</p>';         echo '<input type="text" name="_guests" value="' . $guests  . '" class="widefat" />';         echo '<p>reservation date:</p>';         echo '<input type="text" name="_date" value="' . $date  . '" class="widefat date" />';         echo '<p>reservation time:</p>';         echo '<input type="text" name="_time" value="' . $time  . '" class="widefat time" />';         echo '<input type="submit" name="_time" value="" class="widefat submit" />';        }       function restauranter_save_reservations_meta($post_id, $post) {            if ( !wp_verify_nonce( $_post['reservationmeta_noncename'], plugin_basename(__file__) )) {           return $post->id;           }            // user allowed edit post or page?           if ( !current_user_can( 'edit_post', $post->id ))               return $post->id;            $reservations_meta['_firstname'] = $_post['_firstname'];           $reservations_meta['_lastname'] = $_post['_lastname'];           $reservations_meta['_phone'] = $_post['_phone'];           $reservations_meta['_email'] = $_post['_email'];           $reservations_meta['_guests'] = $_post['_guests'];           $reservations_meta['_date'] = $_post['_date'];           $reservations_meta['_time'] = $_post['_time'];             foreach ($reservations_meta $key => $value) {               if( $post->post_type == 'revision' ) return;               $value = implode(',', (array)$value);               if(get_post_meta($post->id, $key, false)) {                   update_post_meta($post->id, $key, $value);               } else {                   add_post_meta($post->id, $key, $value);               }               if(!$value) delete_post_meta($post->id, $key);           }        }        add_action('save_post', 'restauranter_save_reservations_meta', 1, 2); // save custom fields       function add_new_reservations_columns($reservations_columns) {         $new_columns['cb'] = '<input type="checkbox" />';         $new_columns['_firstname'] = __('first name', '_firstname');         return $new_columns;     }     add_filter('manage_edit-reservations_columns' , 'add_new_reservations_columns'); 

i have tried googling, have tried numerous samples of code, have tried playing code self still no joy.

you need 1 more function add data columns....

function custom_edit-reservations_columns( $column, $post_id ) {   switch ( $column ) {     case "_firstname":       $firstname = get_post_meta($post_id, '_firstname', true);       echo $firstname;     break;   } } add_action( "manage_posts_custom_column", "custom_edit-reservations_columns", 10, 2 ); 

hope helps