c# - 如何将非数组 json 反序列化为实现 List<T> 的子类？

Question

我有以下类(class):

public class PagedClientModelList<T> : List<T>
{
    public int TotalCount { get; set; }
    public int PageSize { get; set; }
    public int CurrentPage { get; set; }
    public int TotalPages { get; set; }
}

两个不同的 json 字符串将被反序列化为该对象的一个​​实例:

• api GET 请求的 http 内容将被反序列化为 List<T>
• api GET 请求的“X-Pagination” header 将反序列化为派生类型的 4 个属性 PagedClientModelList<T>

反序列化为 List<T>没问题:

var result = JsonConvert.DeserializeObject<PagedClientModelList<Person>>
                 (httpResponseMessage.Content.ReadAsStringAsync().Result);

对于json字符串:

[
  {
    "id": 1,
    "name": "Hans"
  },
  {
    "id": 2,
    "name": "Peter"
  },
  {
    "id": 3,
    "name": "Max"
  }
]

但是，当我想反序列化非数组 json header 时，jsonConverter 想要再次反序列化为 List<T>并抛出异常，但我需要将其序列化到子类 PagedClientModelList<T> :

if (httpResponseMessage.Headers.TryGetValues("X-Pagination", out var xPagination))
{
    result = JsonConvert.DeserializeObject<PagedClientModelList<Person>>(xPagination.First());

    // throws exception: Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type [... because it requires json array]
}

对应的header值:

{
  "totalCount": 12,
  "pageSize": 3,
  "currentPage": 1,
  "totalPages": 4
}

如何将非数组 json 反序列化为实现 List<T> 的子类？

Answer 1

好的，这里有一个替代方案，稍微改变一下你的模型:

public class Person
{
    [JsonProperty("id")]
    public int Id { get; set; }

    [JsonProperty("name")]
    public string Name { get; set; }
}

public class PagedClientModelList<T> where T : class, new()
{
    [JsonProperty("totalCount")]
    public int TotalCount { get; set; }

    [JsonProperty("pageSize")]
    public int PageSize { get; set; }

    [JsonProperty("currentPage")]
    public int CurrentPage { get; set; }

    [JsonProperty("totalPages")]
    public int TotalPages { get; set; }

    [JsonProperty("content")]
    public List<T> Content { get; set; }

    public PagedClientModelList()
    {
        Content = new List<T>();
    }
}

测试代码:

class Program
{
    static void Main(string[] args)
    {
        string header = @"{
""totalCount"": 12,
""pageSize"": 3,
""currentPage"": 1,
""totalPages"": 4
}";

        string content = @"[
{
    ""id"": 1,
    ""name"": ""Hans""
},
{
    ""id"": 2,
    ""name"": ""Peter""
},
{
    ""id"": 3,
    ""name"": ""Max""
}
]";

        var modelList = JsonConvert.DeserializeObject<PagedClientModelList<Person>>(header);
        modelList.Content = JsonConvert.DeserializeObject<List<Person>>(content);

        Console.ReadKey();
    }
}