Wert der Benutzerdefinierten Feldes außerhalb Loop in functions.php Datei verwenden

function my_custum_field() { 
        global $wp_query; 
        $postid = $wp_query->post->ID; 
        echo get_post_meta($postid, 'imgright', true);  // Funktioniert :)
} 


function twentytwelve_body_class( $classes ) {
    $background_color = get_background_color();
    $background_image = get_background_image();
    
    $imgright = get_post_meta($postid, 'imgright', true);
    echo $imgright; // Funktioniert NICHT :(
    
    if ( ! is_active_sidebar( 'sidebar-1' ) || is_page_template( 'page-templates/full-width.php' ) )
        $classes[] = 'full-width';


    if ( is_page_template( 'page-templates/front-page.php' ) ) {
        $classes[] = 'template-front-page';
        if ( has_post_thumbnail() )
            $classes[] = 'has-post-thumbnail';
        if ( is_active_sidebar( 'sidebar-2' ) && is_active_sidebar( 'sidebar-3' ) )
            $classes[] = 'two-sidebars';
    }
...