在JavaScript错误中分配变量返回未定义

Question

我不知道这是故障还是我犯的错误。但是我用console.log(record)这就是结果

accountRateId: 6
effectiveEndDate: "2019-09-30T00:00:00"
effectiveStartDate: "2019-09-01T00:00:00"
rate: 100

我有这段代码来分配变量

let rate = record.rate;
let effectiveStartDate = record.effectiveStartDate;
let effectiveEndDate = record.effectiveEndDate;
console.log(rate);

但是console.log（rate）返回未定义。有人可以帮我吗？

更新： 这是来自api的代码

[Authorize("ADMIN")]
[HttpGet("Update/{id}")]
public IActionResult GetUpdate([FromQuery]QueryPagingParametersForNotes inParameters, int id)
{
     List<object> rateList = new List<object>();

     var rateListQueryResults = Database.AccountRates.Where(rate => rate.AccountRateId == id);
     foreach (var oneRate in rateListQueryResults)
     {
     rateList.Add(new
             {
             accountRateId = oneRate.AccountRateId,
             rate = oneRate.RatePerHour,
             effectiveStartDate = oneRate.EffectiveStartDate,
             effectiveEndDate = oneRate.EffectiveEndDate,
             });
      }
     return new JsonResult(rateList);
}

这是javascript中的代码

 $.ajax({
       method: 'GET',
       url: '/API/AccountRates/Update/' + inId
       }).done(function (data) {
             let record = data;
             console.log(record);
             let rate = record.rate;
             let effectiveStartDate = record.effectiveStartDate;
             let effectiveEndDate = record.effectiveEndDate;
             console.log(rate);
             console.log(effectiveStartDate);
                    //Populate the respective input controls with the lesson details.
             $('#rateInput').val(rate);
             $('#startDateInput').val(effectiveStartDate);
             $('#endDateInput').val(effectiveEndDate);

})