从序列化的 Json 中删除空元素

Question

以下是我的Json serialization 代码和CustomResolver，最后检查实际和预期结果之间的差异。我无法从最终结果中删除空元素。有一个可用的选项here，但在我使用ASP.Net Web API 的实际应用程序中，我无权调用JsonConvert.SerializeObject，它是自动调用的，可能需要在Custom Contract Resolver 中执行此操作，任何帮助/指针都会很棒

void Main()
{
    var cbList = new List<CustomerBusiness>();

    cbList.Add(new CustomerBusiness { Id = null, Name = null, PhoneNumber = null });
    cbList.Add(new CustomerBusiness { Id = 1, Name = null, PhoneNumber = null });
    cbList.Add(new CustomerBusiness { Id = null, Name = "Mrinal", PhoneNumber = null });
    cbList.Add(new CustomerBusiness { Id = null, Name = null, PhoneNumber = "9886623261" });
    cbList.Add(new CustomerBusiness { Id = null, Name = null, PhoneNumber = null });
    cbList.Add(new CustomerBusiness { Id = null, Name = null, PhoneNumber = null });

    var serializedData = JsonConvert.SerializeObject(cbList, Newtonsoft.Json.Formatting.Indented,new JsonSerializerSettings { ContractResolver = new CustomResolver() });

    serializedData.Dump();
}

public class CustomResolver : DefaultContractResolver
{
    protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
    {
        IList<JsonProperty> retval = base.CreateProperties(type, memberSerialization);

        retval = retval.Select(p =>
        {
            p.PropertyName = char.ToLower(p.PropertyName[0]) + string.Join("", p.PropertyName.Skip(1));
            p.NullValueHandling = NullValueHandling.Ignore;
            return p;
        }).ToList();

        return retval;
    }
}

public class CustomerBusiness
{
    public int? Id { get; set; }

    public string Name { get; set; }

    public string PhoneNumber { get; set; }
}

实际结果：

[
  {},
  {
    "id": 1
  },
  {
    "name": "Mrinal"
  },
  {
    "phoneNumber": "9886623261"
  },
  {},
  {}
]

预期结果：

[
  {
    "id": 1
  },
  {
    "name": "Mrinal"
  },
  {
    "phoneNumber": "9886623261"
  }
]

Answer 1

var serializedData = JsonConvert.SerializeObject(
    cbList,
    Newtonsoft.Json.Formatting.Indented,new JsonSerializerSettings { ContractResolver = new CustomResolver() });

应该替换为：

var serializedData = JsonConvert.SerializeObject(
    cbList.Where(z => z.Id != null || z.Name != null || z.PhoneNumber != null),
    Newtonsoft.Json.Formatting.Indented,new JsonSerializerSettings { ContractResolver = new CustomResolver() });

Where 子句将确保您仅序列化“非空”数据。