GForm

add_filter( 'gform_field_input', 'gform_cart_subsection', 10, 5 );
add_action( 'gform_pre_submission', 'pre_submission_handler' );
add_filter( 'gform_entry_field_value', 'category_names', 10, 4 );

// gform_cart_subsection() targets a field with CSS class "subsection" and rewrites it with a number of
// input fields: one input per post ID stored in the $favs array.

function gform_cart_subsection($input, $field, $value, $lead_id, $form_id) {

    if( $field["cssClass"] == "subsection" ) {

    $favs = wpfp_get_users_favorites(); // This gives an array of post ID's

        $input = "<br />";

    foreach ( $favs as $fav ){
            $input .= '<label for="fav' . $fav . '">' . get_the_title($fav) . '</label><input name="field_4[]" id="fav' . $fav . '" type="text" value="Add note..."><br/>';
        }
    }

        return $input;
}


function pre_submission_handler($form){

    $_POST["input_4"] = json_encode($_POST["input_4"]);

}

function category_names($value, $field, $lead, $form){

    if(  $field['id'] == 4 ) {

        $newvalue = '';
        $choices = json_decode($value, true);

            foreach($choices as $choice) {
                $new_value .= '<li>'.$choice.'</li>';
            }

            return '<ul>' . $new_value . '</ul>';

    } else {

        return $value;
    }
}