您可以尝试以下操作：

add_action( \'woocommerce_before_add_to_cart_form\', \'add_list_completed_orders\' );
function add_list_completed_orders() {
    // get orders
    $orders = wc_get_orders (
        array (
            \'status\'        => array( \'wc-completed\' ),
            \'type\'          => \'shop_order\',
            \'limit\'         => -1,
            \'return\'        => \'ids\',
            \'customer_id\'   => get_current_user_id(),
        )
    );

    if ( ! empty( $orders ) ) {
        // set value options
        $options = \'\';
        foreach ( $orders as $order_id ) {
            $options .= \'<option value="\' . $order_id . \'">\' . $order_id . \'</option>\';
        }
        // add list
        $form = \'<label for="orders">Select completed orders:</label>\';
        $form .= \'<select id="orders" name="orders">\' . $options . \'</select>\';
        echo $form;
    }

}