JSON反序列化问题：API返回数据解析后对象为null无法获取name字段

问题根源 #

1. JSON结构不匹配：返回的JSON根节点是一个包含d属性的对象，而你直接尝试将整个JSON反序列化为List<Statuses>，序列化工具无法找到匹配的数组结构，因此返回null。
2. 字段类型错误：Statuses类中countedAbsence被定义为string类型，但JSON中该字段是布尔值false，类型不匹配会导致反序列化失败或数据异常。

修正方案 #

1. 新增根对象类

创建对应JSON根结构的类，用来包裹d数组：

public class StatusResponse
{
    [JsonProperty("d")]
    public List<Statuses> StatusList { get; set; }
}

2. 修正Statuses类字段类型

将countedAbsence的类型改为bool：

public class Statuses
{
    [JsonProperty("__type")]
    public string __type { get; set; }
    [JsonProperty("countedAbsence")]
    public bool countedAbsence { get; set; } // 修正为bool类型
    [JsonProperty("description")]
    public string description { get; set; }
    [JsonProperty("name")]
    public string name { get; set; }
    [JsonProperty("schoolSystemExportIdentifier")]
    public string schoolSystemExportIdentifier { get; set; }
    [JsonProperty("shortCode")]
    public string shortCode { get; set; }
    [JsonProperty("shortName")]
    public string shortName { get; set; }
    [JsonProperty("statusId")]
    public string statusId { get; set; }
}

3. 修改反序列化逻辑

先反序列化为根对象，再获取内部的StatusList：

// 替换原反序列化代码
var responseDto = SerializerHelper.Deserialize<StatusResponse>(output);
var dtoDirectories = responseDto.StatusList;

// 循环输出name字段
foreach (var status in dtoDirectories)
{
    Console.WriteLine(status.name);
}

完整修正后的代码 #

using CompassAPI;
using Newtonsoft.Json;

var client = new HttpClient();
var request = new HttpRequestMessage(HttpMethod.Post, "{Removed for security}");
request.Headers.Add("CompassApiKey", "{removed for security}");
request.Headers.Add("Cookie", "{removed for security}");

var content = new StringContent("{\"schoolSystemType\": \"aus\"}", null, "application/json");
request.Content = content;

var response = await client.SendAsync(request);
response.EnsureSuccessStatusCode();
string output = await response.Content.ReadAsStringAsync();
Console.WriteLine(output);

// 修正后的反序列化逻辑
var responseDto = SerializerHelper.Deserialize<StatusResponse>(output);
var dtoDirectories = responseDto.StatusList;

foreach (var status in dtoDirectories)
{
    Console.WriteLine(status.name);
}

Console.ReadLine();

// 新增根对象类
public class StatusResponse
{
    [JsonProperty("d")]
    public List<Statuses> StatusList { get; set; }
}

public class Statuses
{
    [JsonProperty("__type")]
    public string __type { get; set; }
    [JsonProperty("countedAbsence")]
    public bool countedAbsence { get; set; }
    [JsonProperty("description")]
    public string description { get; set; }
    [JsonProperty("name")]
    public string name { get; set; }
    [JsonProperty("schoolSystemExportIdentifier")]
    public string schoolSystemExportIdentifier { get; set; }
    [JsonProperty("shortCode")]
    public string shortCode { get; set; }
    [JsonProperty("shortName")]
    public string shortName { get; set; }
    [JsonProperty("statusId")]
    public string statusId { get; set; }
}

内容的提问来源于stack exchange，提问作者Michael van der Veeke