无法从Angular中的Web API获得响应

Question

这是我从WebAPI返回数据的方式：

[HttpGet]
[Route("ProcessHistory")]
public HttpResponseMessage ProcessHistory()
{
    HttpResponseMessage response = new HttpResponseMessage();
    try
    {

        IProcessManagement ProcessManagement = serviceFactory.CreateProcessManagement();
        List<Process> listProcess = ProcessManagement.Get().ToList();
        response = Request.CreateResponse<IEnumerable<Process>>(HttpStatusCode.OK, listProcess);
    }
    catch (Exception ex)
    {
        response = Request.CreateResponse(HttpStatusCode.BadRequest, ex.Message);
    }
    return response;
}

角度：

调用Angular服务的Angular Component方法：

getProcessScheduleStatus(){
  this.Service.getProcessScheduleStatus(this.ApiUrl + ConstAPIUrls.ProcessScheduleStatus).subscribe(
    (next: ProcessScheduleStatus[]) => {
      alert('Got status successfully..!!');
      console.log('Processes: ');
      console.log(next);
      this.result.IsSuccess = true;
      this.result.SuccessMessage = 'Success';
      this.openModal(this.result);
    },
    error => {
      alert('Error');
      if (error.status == 400) {
        this.result.IsSuccess = false;
        this.result.ErrorMessage = JSON.parse(JSON.stringify(error.error));
        this.openModal(this.result);
      }
      else {
        //Parse response for other error status
        this.result.IsSuccess = false;
        this.result.ErrorMessage = JSON.parse(JSON.stringify(error.message));
        this.openModal(this.result);
      }        
    },
    () => {
      //process to be run after web api request completes
    }
  );
}

正在调用Web api的角度服务：

getProcessScheduleStatus(apiUrl: string):Observable<ProcessScheduleStatus[]>{
  return this._httpClient.get(apiUrl, this.httpOptions).map((result: ProcessScheduleStatus[]) => {
    alert('web api execued');
    if (result != null && result != undefined) {
      return result;
    }
    else {
      return result;
    }
  });
}

这是浏览器XHR结果：

当Angular服务访问Web api时，但当Web api返回响应时，它将直接转到组件错误处理程序。

如何从响应中正确读取数据？

Chrome XHR中的故障请求标头：