如何使用Stripe.NET预览分段计算？

Question

我正在按照Previewing Proration上的Stripe文档中提供的示例，使用Stripe.NET库来查找客户从计划A升级到计划B时所收取的费用。

但是，当我在文档中使用代码示例时，我会得到一个错误：

UpcomingInvoiceOptions options = new UpcomingInvoiceOptions()
{
    CustomerId = "cus_XXXXXXXXXXXXX",
    SubscriptionProrationDate = DateTime.UtcNow,
    SubscriptionItems = new List<InvoiceSubscriptionItemOptions>()
    {
        new InvoiceSubscriptionItemOptions()
        {
            Id = "si_XXXXXXXXXXXXXX", // Current Sub Item
            PlanId = "plan_XXXXXXXXXXXX" // New plan
        }
    }
};
InvoiceService service = new InvoiceService();
var result = service.Upcoming(options);

最后一行抛出一个Stripe.StripeException：You cannot update a subscription item without a subscription.

Answer 1

如果您不首先调用options.SubscriptionId，则此操作需要service.Get字段。

以下代码产生正确的结果：

UpcomingInvoiceOptions options = new UpcomingInvoiceOptions()
{
    CustomerId = "cus_XXXXXXXXXXXXX",
    SubscriptionId = "sub_XXXXXXXXXXXX",
    SubscriptionProrationDate = DateTime.UtcNow,
    SubscriptionItems = new List<InvoiceSubscriptionItemOptions>()
    {
        new InvoiceSubscriptionItemOptions()
        {
            Id = "si_XXXXXXXXXXXXXX", // Current Sub Item
            PlanId = "plan_XXXXXXXXXXXX" // New plan
        }
    }
};
InvoiceService service = new InvoiceService();
var result = service.Upcoming(options);