如何将React.js中的JSON值传递至.NET抽象类参数？

你遇到的问题本质是.NET在反序列化抽象类参数时，无法通过JSON自动识别对应的具体实现类，再加上代码存在字段缺失、属性引用错误的问题，按以下步骤修改即可： #

1. 配置抽象类反序列化的类型鉴别规则 #

.NET反序列化抽象/父类对象时，需要额外的标识字段判断具体要实例化哪个子类，按你使用的序列化组件二选一配置：

如果你使用.NET默认的System.Text.Json序列化 #

给你的ConcreteRegistryInfo抽象类加上派生类类型标识配置：

using System.Text.Json.Serialization;

[DataContract]
[KnownType(typeof(ConcreteOtherRegistry))]
[KnownType(typeof(ConcreteForeignerRetailRegistry))]
[KnownType(typeof(ConcreteUndetailedRegistry))]
[KnownType(typeof(ConcreteRetailRegistry))]
[KnownType(typeof(ConcretePublicRegistry))]
[KnownType(typeof(ConcreteCorporateRegistry))]
// 给每个子类配置对应的鉴别标识，其余子类按需补充该配置即可
[JsonDerivedType(typeof(ConcreteRetailRegistry), typeDiscriminator: "RetailRegistry")]
public abstract class ConcreteRegistryInfo
{
    // 原有代码不变
}

如果你使用Newtonsoft.Json序列化 #

在Program.cs/Startup.cs里配置序列化时开启类型名称输出：

builder.Services.AddControllers()
    .AddNewtonsoftJson(options =>
    {
        options.SerializerSettings.TypeNameHandling = TypeNameHandling.Auto;
    });

2. 补全前端JSON的必填字段 #

你的ConcreteRegistryInfo抽象类标记了4个必填的DataMember，现有APPLICATION对象缺少Status、LastUpdated、OperationRefNo三个字段，必须补全，同时加上第一步的类型鉴别字段。
调整后的APPLICATION示例：

let APPLICATION = {
  // System.Text.Json对应上面配置的标识，Newtonsoft.Json则填"$type": "你的命名空间.ConcreteRetailRegistry, 你的程序集名称"
  "$type": "RetailRegistry",
  IdentityNumber:IdentityNumber,
  Name:Name,
  SurName:SurName,
  FatherName:FatherName,
  MotherName:MotherName,
  PlaceOfBirth:PlaceOfBirth,
  Gender:Gender,
  Email:Email,
  DateOfBirth:DateOfBirth,
  DayOfBirth:DayOfBirth,
  MonthOfBirth:MonthOfBirth,
  YearOfBirth:YearOfBirth,
  GsmNumber:GsmNumber,
  PhoneNumber:PhoneNumber,
  Retired:Retired,
  Address:Address,
  Oid:Oid,
  // 补全抽象类必填字段，值按实际业务逻辑赋值即可
  Status: 1,
  LastUpdated: new Date().getTime(),
  OperationRefNo: 10001
}

3. 修复后端接口代码错误 #

你定义的SaveApplicationParameters类只有registryInfo属性，但接口中直接读取不存在的application属性，必然为空。修改接口逻辑，用传入的registryInfo构造你需要的ConcreteApplication对象：

[HttpPost]
public object[] SaveApplication([FromBody] SaveApplicationParameters saveApplicationParameters)
{
    // 把传入的registryInfo强转为对应实现类
    var retailRegistry = saveApplicationParameters.registryInfo as ConcreteRetailRegistry;
    // 构造ConcreteApplication对象，属性按你的业务逻辑赋值
    ConcreteApplication application = new ConcreteApplication
    {
        RegistryInfo = retailRegistry,
        // 其余属性按需赋值
    };

    try
    {
        Com.BS.WaterSupplyAndSeverage.Services.WaterSupplyAndSewerage wssService = new Com.BS.WaterSupplyAndSeverage.Services.WaterSupplyAndSewerage();
        wssService.SaveApplication(application);
        object[] result = new object[1];
        result[0] = application.ApplicationNo;
        return result;
    }
    catch (Exception e)
    {
        FileLogger.Error(CLASS_NAME, "SaveApplication", e.Message, e.StackTrace, application, policy);
        BSCommunicationException commException = PrepareCommunicationException(e);
        throw new FaultException<BSCommunicationException>(commException, new FaultReason(commException.ExceptionMessage));
    }
}

4. 前端请求可选优化 #

给axios请求显式指定JSON请求头，避免部分环境下序列化异常：

const body = { registryInfo: APPLICATION };
axios.post('https://localhost:44396/api/SaveApplication', body, {
  headers: {
    'Content-Type': 'application/json'
  }
})
.then(async response => {
  SuccessOperation({ RESPONS_DATA: await response.data });
})
.catch(() => {
  FailedOperation({ RESPONSE_DATA: null })
});

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