.Net core Web API 将 json/model 值设置为 NULL

Question

我有一个 .Net core Web API，它接受以下 JSON：(RequestModel)

{
    "isSpecimen": true,   
    "forms": {
        "cyber": {           
            "abc1": {
                "formOrder": 1,
                "endNumber": "1",
                "selected": true,
                "aggLimit": 5000000.0,
                "Date": "2016-12-14T00:00:00.00Z"
            },
            "abc2": {
                "formOrder": 2,
                "endNumber": "4",
                "selected": false,
                "aggLimit": 50000.0,
                "Date": "2019-12-14T00:00:00.00Z"
            },
        }
    }
}

以下是模型类：

public class RequestModel
{
   public FormsModel Forms { get; set; }
   public bool IsSpecimen { get; set; }
}

public abstract class BaseFormInfo
{
    public bool Selected { get; set; }
    public int? FormOrder { get; set; }
    public virtual string FormKey { get; set; }
}

public class FormsModel
{
    public ExcessFormsModel? Excess { get; set; }
    public CyberFormsModel? Cyber { get; set; }
}

public class CyberFormsModel
{
    public Abc1? abc1 { get; set; }
    public Abc2? abc2 { get; set; }
    public Abc3? abc3 { get; set; }
}

public class Abc1: BaseFormInfo
{
     public override string FormKey => "Abc1";
     public decimal? aggLimit{ get; set; }
     public DateTime? Date { get; set; }
     public string? endNumber{ get; set; }
}

我想更新模型，将以下类的字段值设置为 NULL “已选择”：true

例如：“abc1”已“选择”：true

"cyber": {           
        "abc1": {
            "formOrder": null,
            "endNumber": null,
            "selected": true,
            "aggLimit": null,
            "Date": null
        },
}

如何迭代 JSON 数据以将值设置为 NULL？

Answer 1

您可以通过使用自定义模型绑定来完成此操作。首先将JSON字符串解析为JObject，然后遍历JSON结构找到cyber下的对象。对于每个网络，检查“selected”属性是否为true。如果是这样，请将除“selected”之外的所有属性设置为空。修改 JSON 后，将 JObject 重新转换为字符串。此外，您可以通过将 JsonIgnore 添加到 FormKey 属性来隐藏 FormKey。这是一个示例，您可以将其用作参考：

public abstract class BaseFormInfo
{
     public bool Selected { get; set; }
     public int? FormOrder { get; set; }
     [JsonIgnore]
     public virtual string FormKey { get; set; }
}

我的控制器：

[HttpPost]

public IActionResult Update([ModelBinder(typeof(MyModelBinder))]  RequestModel request)

{
  
    return Ok(request);

}

我的模型绑定器：

public class MyModelBinder : IModelBinder
{
     public async Task BindModelAsync(ModelBindingContext bindingContext)
     {
         if (bindingContext == null)
         {
             throw new ArgumentNullException(nameof(bindingContext));
         }

         var jsonString = bindingContext.ActionContext.HttpContext.Request.Body;
         using var reader = new StreamReader(jsonString);
         var body = await reader.ReadToEndAsync();

         if (string.IsNullOrEmpty(body))
         {
             return;
         }
         var inputJson = JObject.Parse(body);
         var forms = inputJson["forms"];
         var cyber = forms["cyber"];
         foreach (var form in cyber)
         {
             if ((bool)form.First["selected"])
             {
                 foreach (var property in form.First.Children<JProperty>())
                 {
                     if (property.Name != "selected")
                     {
                         property.Value = null;
                     }
                 }
             }
         }

         var outputJson = inputJson.ToString();
         var requestModel = JsonConvert.DeserializeObject<RequestModel>(outputJson);

         bindingContext.Result = ModelBindingResult.Success(requestModel);
     }
}

当我发送数据时： API返回数据：