Web API C#中没有数据只显示括号答案

【问题标题】：No data displayed only brackets in web API C#Web API C#中没有数据只显示括号
【发布时间】：2020-01-07 13:24:29
【问题描述】：

我对 C# 中的 Web API 很陌生。

这是我的 JSON 响应：

{
    "<chart_type>": [
        { "name": "entity" },
        { "display_name": "entity display name" },
        {
            "kpi": [
                {
                    "name":"<kpi>",
                    "display_name":"test",
                    "required": [
                        { "test": "test" },
                        { "test1": "test" }
                        ],
                    "optional": [        
                        { "test": "test" },
                        { "test": "test" }
                        ],
                    "objects": {
                        "<Fieldname>": 
                        {
                            "display_name":"<entity display name>",
                            "type": "<select or text>",
                            "default": "default value (already selected)",
                            "list": {
                                "<id>": "<value>"
                            }
                        }
                    }
                }
            ]
        }
    ]
}

但在我使用邮递员之后，这是显示：

这是我的定义DTO

public partial class Test
{
    [JsonProperty("<chart_type>", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
    public ChartType[] chart_type { get; set; }
}

public partial class ChartType
{
    [JsonProperty("name", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
    public string entity_name { get; set; }

    [JsonProperty("display_name", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
    public string entity_display_name { get; set; }

    [JsonProperty("kpi", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
    public Kpi[] Kpi { get; set; }
}

public partial class Kpi
{
    [JsonProperty("name", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
    public string kpi_name { get; set; }

    [JsonProperty("display_name", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
    public string kpi_display_name { get; set; }

    [JsonProperty("required", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
    public RequiredElement[] kpi_required { get; set; }

    //[JsonProperty("optional", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
    //public Optional[] kpi_optional { get; set; }

    [JsonProperty("objects", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
    public Objects Objects { get; set; }
}

public partial class RequiredElement
{
    [JsonProperty("test", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
    public string Test { get; set; }

    [JsonProperty("test1", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
    public string Test1 { get; set; }
}

public partial class Objects
{
    [JsonProperty("<Fieldname>", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
    public Fieldname Fieldname { get; set; }
}

public partial class Fieldname
{
    [JsonProperty("display_name", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
    public string DisplayName { get; set; }

    [JsonProperty("type", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
    public string Type { get; set; }

    [JsonProperty("default", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
    public string Default { get; set; }

    //[JsonProperty("list", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
    //public List List { get; set; }
}

【问题讨论】：

标签： c# asp.net-web-api

【解决方案1】：

将[DataContract] 和[DataMember(EmitDefaultValue = false)] 用于您的DTO。

您已经覆盖了默认的 ASP.NET JSON 序列化程序，如果您使用的是 ASP.NET Web API，那么您应该知道默认的 JSON 序列化程序不是 DataContractJsonSerializer (DCJS)，而是 JSON.NET反而。因此，除非您将 JsonMediaTypeFormatter 显式配置为使用 DCJS，否则您需要另一个属性来获得相同的行为（JsonProperty 及其 DefaultValueHandling 属性）。

[DataContract]
public partial class Fieldname
{
[DataMember(EmitDefaultValue = false)]
[JsonProperty("display_name", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
public string DisplayName { get; set; }

[JsonProperty("type", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
public string Type { get; set; }

[JsonProperty("default", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
public string Default { get; set; }

//[JsonProperty("list", Required = Required.DisallowNull, NullValueHandling = NullValueHandling.Ignore)]
//public List List { get; set; }
}

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【讨论】：

您好，先生，我尝试将其更改为 public class ChartType { public string kpi_name { get;放; } 公共字符串 kpi_display_name { 获取；放; } 公共列表 kpi { 获取；放; } } 公共类 RootObject { public List chart_type { get;放; } } 当我调用 RootObject 时，它不显示数据第一个数据，但是当我尝试调用公共类 ChartType 时，它将显示前两个值，第三个为空。我不能打电话给第三个，这是我的问题之一。
[HttpGet] public HttpResponseMessage definition() { var result = _definitionRepository.definition(); if (result == null) { return Request.CreateErrorResponse(HttpStatusCode.BadRequest, "Bad request"); } return Request.CreateResponse(HttpStatusCode.OK, result); }
如果可能，还需要存储库代码.. 并将DataMember 添加到所有属性中。
公共类 DefinitionRepository : IDefinitionRepository { private HistogramEntities _db = new HistogramEntities(); public List definition() { var results = _db.Database.SqlQuery("get_definition_list").ToList();返回结果； } }

【解决方案2】：

public List<Root> definition()
        {
            var all = _db
                .kpi_definition
                .Include("KPI")
                .Select(dl => new Root
                {
                    //chart_type = dl.chart_type,
                    chart_type = new List<Chart>
                    {
                       new Chart { entity_name = dl.entity_name ,
                                   entity_display_name = dl.entity_display_name,
                                   kpi = new List<KPI>
                                   {
                                      new KPI {
                                               kpi_name = dl.kpi_name,
                                               kpi_display_name = dl.kpi_display_name,
                                               required = new List<Required>
                                               {
                                                   new Required
                                                   {
                                                       //kpi_required = dl.kpi_required
                                                   }
                                               },
                                               optional = new List<Optional>
                                               {
                                                   new Optional
                                                   {
                                                       //kpi_optional = dl.kpi_optional
                                                   }
                                               },
                                               objects = new List<Objects>
                                               {
                                                   new Objects
                                                   {
                                                       field_name = new List<FieldName>
                                                       {
                                                           new FieldName
                                                           {
                                                            entity_display_name = dl.entity_display_name,
                                                            type = "Select or Text",
                                                            @default = "default value(already selected)",
                                                            list = "",
                                                            ID = dl.ID
                                                           }
                                                       }

                                                   }
                                               }
                                              }
                                   }
                                 }
                    }
                }).ToList();
            return all;
        }

【讨论】：