PayPal API验证错误：商品金额必须总计为指定的金额小计（如果未指定金额明细，则为总计）

Question

我当前遇到错误（如标题中所述）。我不知道出了什么问题或我遇到的问题。我确定错误中提到的所有值都相同，但仍然会弹出相同的错误。

我的目的是使所有值相同以解决错误。

这是我的错误的完整说明：

{
  "name": "https://stackoverflow.com/VALIDATION_ERROR",
  "details": [
    {
      "field": "transactions[0]",
      "issue": "Item amount must add up to specified amount subtotal (or total if amount details not specified)"
    }
  ],
  "message": "Invalid request - see details",
  "information_link": "https://developer.paypal.com/docs/api/payments/#errors",
  "debug_id": "67a354f1a8fc7"
}

请帮助！

以下是我的参考代码：

// scList has 2 values inside.
List<UserShoppingCartDAO> scList = UserShoppingCartDAO.GetCartOfUser(uID);

List<Item> itms = new List<Item>();
ItemList itemList = new ItemList();
decimal deliveryCharges = 0;
string deliveryChargesStr = "";
decimal postagePackingCost = 0;
decimal examPaperPrice = 0;
int quantityOfExamPapers = 0;
decimal subtotal = 0;
decimal total = 0;
var transactionDetails = new Details();
var transactionAmount = new Amount();
Transaction tran = new Transaction();

for (int iCounter = 0; iCounter < scList.Count; iCounter++)
{
    Product p = Product.getProduct(scList[iCounter].ProductID.ToString());
    deliveryCharges = p.price * 0.05m;
    deliveryChargesStr = deliveryCharges.ToString();
    postagePackingCost = 10m;
    examPaperPrice = p.price;
    quantityOfExamPapers = scList[iCounter].ProductQuantity;
    subtotal = (quantityOfExamPapers * examPaperPrice);
    total = subtotal + postagePackingCost;

    var examPaperItem = new Item();
    examPaperItem.name = p.productName;
    examPaperItem.currency = "SGD";
    examPaperItem.price = total.ToString();
    examPaperItem.sku = p.productID.ToString();
    examPaperItem.description = p.productDesc;
    examPaperItem.quantity = quantityOfExamPapers.ToString();

    itms.Add(examPaperItem);
    itemList.items = itms;

    //  var transactionDetails = new Detail
    transactionDetails.tax = "0";
    if (transactionDetails.shipping == null)
    {
        transactionDetails.shipping = postagePackingCost.ToString();
    }
    else
    {
        decimal total2 = decimal.Parse(transactionDetails.shipping) + postagePackingCost;
        transactionDetails.shipping = total2.ToString();
    }

    if (transactionDetails.subtotal == null)
    {
        transactionDetails.subtotal = subtotal.ToString();
    }
    else
    {
        decimal total2 = decimal.Parse(transactionDetails.subtotal) + subtotal;
        transactionDetails.subtotal = total2.ToString();
    }

    //transactionDetails.shipping = postagePackingCost.ToString();
    //transactionDetails.subtotal = subtotal.ToString("0.00");

    //    var transactionAmount = new Amount();
    transactionAmount.currency = "SGD";

    if (transactionAmount.total == null)
    {
        transactionAmount.total = total.ToString();
    }
    else
    {
        decimal total2 = decimal.Parse(transactionAmount.total) + total;
        transactionAmount.total = total2.ToString();
    }

    transactionAmount.details = transactionDetails;

    //   Transaction tran = new Transaction();

    tran.description = scList[0].ProductDescription;
    tran.invoice_number = Guid.NewGuid().ToString();
    tran.amount = transactionAmount;

    //    transaction.item_list = new List<Item>();
    tran.item_list = itemList;
    transactionList.Add(tran);
}
transactionList.Remove(transactionList[1]);
//Authenticate with paypal
var config = ConfigManager.Instance.GetProperties();
var accessToken = new OAuthTokenCredential(config).GetAccessToken();

//Get APIContent Object
var apiContext = new APIContext(accessToken);

var payer = new Payer();
payer.payment_method = "paypal";

var redirectUrls = new RedirectUrls();
redirectUrls.cancel_url = "http://localhost60681/Cancel.aspx";
redirectUrls.return_url = "http://localhost:60681/CompletePurchase.aspx";

var payment = Payment.Create(apiContext, new Payment
{

    intent = "sale",
    payer = payer,
    transactions = transactionList,
    redirect_urls = redirectUrls
});

Session["paymentId"] = payment.id;

foreach (var link in payment.links)
{
    if (link.rel.ToLower().Trim().Equals("approval_url"))
    {
        Response.Redirect(link.href);
    }
}