Paypal api – Issue Patching Order Amount with Breakdown – Paypal Checkout NET SDK

I’m running into the same issue.

System.Runtime.Serialization.SerializationException: Type ‘PayPalCheckoutSdk.Orders.AmountWithBreakdown’ with data contract name ‘AmountWithBreakdown:http://schemas.datacontract.org/2004/07/PayPalCheckoutSdk.Orders‘ is not expected. Consider using a DataContractResolver if you are using DataContractSerializer or add any types not known statically to the list of known types – for example, by using the KnownTypeAttribute attribute or by adding them to the list of known types passed to the serializer.

The call never makes it to PayPal for a response because it is failing to serialize the request. The only way I’ve been able to get it to work is by generating my own request without the SDK. This isn’t production ready code. I was just testing to see if it would work if I crafted the request myself, and it does.

var ppe = PayPalClient.environment(productLine);

        var accessTokenClient = new HttpClient(ppe);
        var accessTokenRequest = new AccessTokenRequest(ppe, null);

        var accessTokenResponse = Task.Run(async () =>
        {
            var httpResponse = await accessTokenClient.Execute(accessTokenRequest);
            return httpResponse;
        }).Result;

        if (accessTokenResponse.StatusCode != HttpStatusCode.OK)
        {
            Logger.Error("[PayPalRestService] Unable to get access token.");
            return null;
        }
        
        var accessToken = accessTokenResponse.Result<AccessToken>();

        var client = new RestClient(ppe.BaseUrl());
        client.AddDefaultHeader("Authorization", $"Bearer {accessToken.Token}");


        var body = BuildUpdateTaxPatchRequest(cart, paypalOrder);
        var request = new RestRequest($"/v2/checkout/orders/{paypalOrder.Id}")
            .AddJsonBody(JsonConvert.SerializeObject(body));

        var response = client.Patch(request);

        if (response.StatusCode == HttpStatusCode.NoContent)
        {
            return GetOrder(paypalOrder.Id, productLine);
        }




private static List<Patch<object>> BuildUpdateTaxPatchRequest(ICart cart, Order paypalOrder)
    {
        //Doc: https://developer.paypal.com/docs/api/orders/v2/#orders_patch

        var subtotal = $"{cart.GetSubTotal():N2}";
        var shipping = $"{cart.GetShippingTotal():N2}";
        var discount = $"{cart.GetOrderDiscountTotal():N2}";
        var tax = $"{cart.GetTaxTotal():N2}";
        var total = double.Parse(tax, CultureInfo.GetCultureInfo("en-US")) + double.Parse(shipping, CultureInfo.GetCultureInfo("en-US")) + double.Parse(subtotal, CultureInfo.GetCultureInfo("en-US")) - double.Parse(discount, CultureInfo.GetCultureInfo("en-US"));
        var strTotal = total.ToString("0.00", CultureInfo.GetCultureInfo("en-US"));


        var updates = new AmountWithBreakdown()
        {
            CurrencyCode = paypalOrder.PurchaseUnits.First().AmountWithBreakdown.CurrencyCode,
            Value = strTotal,
            AmountBreakdown = new AmountBreakdown
            {
                ItemTotal = new Money
                {
                    CurrencyCode = cart.Currency.CurrencyCode,
                    Value = subtotal
                },
                Shipping = new Money
                {
                    CurrencyCode = cart.Currency.CurrencyCode,
                    Value = shipping
                },
                TaxTotal = new Money
                {
                    CurrencyCode = cart.Currency.CurrencyCode,
                    Value = tax
                },
            }
        };

        var patches = new List<Patch<object>>
        {
            new Patch<object>
            {
                Op= "replace",
                Path= "/purchase_units/@reference_id=='default'/amount",
                Value = updates
            }
        };

        return patches;
    }
}