C#调用UPS地址验证API时JSON反序列化列表错误排查

错误信息 #

{"Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[OAuthWinForms2024.Objects.Candidate]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.
To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List) that can be deserialized from a JSON object. JsonObjectAttribute can also be added to the type to force it to deserialize from a JSON object.
Path 'XAVResponse.Candidate.AddressClassification', line 1, position 213."}

点击事件请求代码 #

private async void btnValidateAddress_Click(object sender, EventArgs e)
{
    var serviceCollection = new ServiceCollection();
    ConfigureServices(serviceCollection);
    var services = serviceCollection.BuildServiceProvider();
    var _httpClientFactory = services.GetRequiredService<IHttpClientFactory>();
    var client = _httpClientFactory.CreateClient();

    var accesstoken = txtAccessToken.Text.ToString();

    Candidate candidate = new Candidate();
    Root addressVerification = new Root();
    AddressKeyFormat addressKeyFormat = new AddressKeyFormat();
    List<string> addressline = new List<string> { "1109 9th", "", "" };

    addressKeyFormat.AddressLine = addressline;
    addressKeyFormat.PoliticalDivision1 = "AZ";
    addressKeyFormat.PoliticalDivision2 = "Phoenix";
    addressKeyFormat.PostcodePrimaryLow = "85007";
    addressKeyFormat.PostcodeExtendedLow = "";
    addressKeyFormat.Urbanization = "";
    addressKeyFormat.CountryCode = "US";

    candidate.AddressKeyFormat = addressKeyFormat;

    string jsonString = Newtonsoft.Json.JsonConvert.SerializeObject(candidate);

    var jsonStringV = @"{XAVRequest: " + jsonString + "}";
    JObject myjson = JObject.Parse(jsonStringV);

    client.DefaultRequestHeaders.Add("Authorization", "Bearer " + accesstoken);

    var postData = new StringContent(myjson.ToString(), Encoding.UTF8, "application/json");
    var Requestoption = "3";
    var Version = "v1";
    var request = await client.PostAsync("https://onlinetools.ups.com/api/addressvalidation/" + Version + "/" + Requestoption + "?regionalrequestindicator=string&maximumcandidatelistsize=1", postData);
    var response = await request.Content.ReadAsStringAsync();

    // 错误发生在以下语句
    Root addressVerification2 = JsonConvert.DeserializeObject<Root>(response);
}

实体类定义 #

using System.Collections.Generic;

namespace OAuthWinForms2024.Objects
{
    // Root myDeserializedClass = JsonConvert.DeserializeObject<Root>(myJsonResponse);
    public class AddressClassification
    {
        public string Code { get; set; }
        public string Description { get; set; }
    }

    public class AddressKeyFormat
    {
        public string ConsigneeName { get; set; }
        public string AttentionName { get; set; }
        public List<string> AddressLine { get; set; }
        public string Region { get; set; }
        public string PoliticalDivision2 { get; set; }
        public string PoliticalDivision1 { get; set; }
        public string PostcodePrimaryLow { get; set; }
        public string PostcodeExtendedLow { get; set; }
        public string Urbanization { get; set; }
        public string CountryCode { get; set; }
    }

    public class Alert
    {
        public string Code { get; set; }
        public string Description { get; set; }
    }

    public class Candidate
    {
        public AddressClassification AddressClassification { get; set; }
        public AddressKeyFormat AddressKeyFormat { get; set; }
    }

    public class Response
    {
        public ResponseStatus ResponseStatus { get; set; }
        public List<Alert> Alert { get; set; }
        public TransactionReference TransactionReference { get; set; }
    }

    public class ResponseStatus
    {
        public string Code { get; set; }
        public string Description { get; set; }
    }

    public class Root
    {
        public XAVResponse XAVResponse { get; set; }
    }

    public class TransactionReference
    {
        public string CustomerContext { get; set; }
    }

    public class XAVResponse
    {
        public Response Response { get; set; }
        public string ValidAddressIndicator { get; set; }
        public string AmbiguousAddressIndicator { get; set; }
        public string NoCandidatesIndicator { get; set; }
        public AddressClassification AddressClassification { get; set; }
        public List<Candidate> Candidate { get; set; }
    }
}

我认为自己已经正确使用了列表，但仍出现错误，希望得到解决方法。

内容的提问来源于stack exchange，提问作者SuperSavior