使用 POSTMAN 客户端的 C# web API POST JSON 数据在 FromBody 中始终为 NULL

Question

我有一个包含模型的 Web Api -

 public class Assessments
{
    public List<AssessmentResult> Results { get; set; }
}

public class AssessmentResult
{
    public int? AssessorId { get; set; }
    public int? AssessmentId { get; set; }
    public int? CentreId { get; set; }
    public int? BatchId { get; set; }
    public DateTime AssessmentDate { get; set; }

和 Controller -

[HttpPost]
    [ActionName("SetAssessmentResults")]
    public HttpResponseMessage SetAssessmentResults([FromBody] Assessments assessments)
    {
        try
        {

            string sproc = ConfigurationManager.AppSettings["ASSESSORAPP_InsertAssessmentsStaging"];
            //_dt = Helper.ToDataTable(assessments); use this if sending list doesnt work

            Mapper.Initialize(cfg =>
            {
                //cfg.CreateMissingTypeMaps = false;
                cfg.CreateMap<AssessmentResult, AssessmentTable>().IgnoreAllNonExisting();

                //cfg.IgnoreUnmapped();
            });
            List<AssessmentTable> assessmentTable = Mapper.Map<List<AssessmentResult>, List<AssessmentTable>>(assessments.Results);
            Mapper.Configuration.AssertConfigurationIsValid();

            string isSuccess = _db.InsertAssessmentResults(sproc, assessmentTable);
            if (isSuccess.Split('$')[0].ToLower() == "success")
            {
                return Request.CreateResponse(HttpStatusCode.OK, isSuccess);
            }
            else if (isSuccess.Split('$')[0].ToLower() == "duplicate")
            {
                return Request.CreateResponse(HttpStatusCode.OK, isSuccess);
            }
            else
            {
                return Request.CreateResponse(HttpStatusCode.OK, isSuccess);
            }
        }
        catch (Exception ex)
        {
            return Request.CreateResponse(HttpStatusCode.InternalServerError, ex);
        }
    }

客户端，我使用的是 Postman Chrome 扩展程序。我正在发送正文中包含 JSON 数据的 POST 请求。但是，我没有在 Controller 中获取 JSON 数据(评估对象始终显示 NULL 值)

assessments object showing NULL value

在客户端，我请求使用 PostMan Chrome 扩展

PostMan Client sending request

这是我的 JSON 数据:

    {
"assessment":
[{
      "AssessorId": 3,
      "AssessmentId": 123,
      "CentreId": 1,
      "BatchId": null,
      "AssessmentDate": "2016-09-30T00:00:00",

    },{
     "AssessorId": 2,
      "AssessmentId": 123,
      "CentreId": 1,
      "BatchId": null,
      "AssessmentDate": "2016-09-30T00:00:00",
    }]
    }

我还添加了 Content-Type : application/json

请帮我解决这个问题。谢谢!

Answer 1

在您的类(class)Assessments中，您将包含 AssessmentResult 列表的属性命名为“Results”，但是当您发送帖子时，您将属性命名为“assessment "它应该是 "Results"(考虑到您有默认的序列化程序配置，例如:序列化时没有属性名称到小驼峰大小写)

尝试:

  {
     "Results":[{
                 "AssessorId": 3,
                 "AssessmentId": 123,
                 "CentreId": 1,
                 "BatchId": null,
                 "AssessmentDate": "2016-09-30T00:00:00",

               },
               {
                 "AssessorId": 2,
                 "AssessmentId": 123,
                 "CentreId": 1,
                 "BatchId": null,
                 "AssessmentDate": "2016-09-30T00:00:00",
               }]
 }

另外，作为一种好的做法，您应该在类的构造函数中实例化列表例如:

public class Assessments
{
    public Assessments()
    {
         Results = new List<AssessmentResult>();
    }
    public List<AssessmentResult> Results { get; set; }
}