DateTime的动态类型格式，c＃

Question

下面有一个json结构，其格式随每个请求而变化，并将其作为POST有效负载发送到.Net MVC 4。

{"id":40388111,"parameters":[{"fid":40388138,"all":true,"isaccounts":true},{"fid":40388139,"value":"2014-10-02T00:00:00.000Z"}],"output":"json","start":0,"limit":25}

控制器操作如下：

[HttpPost]
public async Task<HttpResponseMessage> Execute(dynamic payload)
{
    string postData = Convert.ToString(payload);
    var vm = await _service.Execute(postData);
    return Request.CreateResponse(HttpStatusCode.OK, vm, new MediaTypeHeaderValue("application/json"));
}

问题是字符串postData变为：

{
  "id": 40388111,
  "parameters": [
    {
      "fid": 40388138,
      "all": true,
      "isaccounts": true
    },
    {
      "fid": 40388139,
      "value": "2014-10-02T00:00:00Z"
    }
  ],
  "output": "json",
  "start": 0,
  "limit": 25
}

您会注意到日期中缺少的毫秒数，这会导致接收此postData字符串的服务中出现问题。如何使postData字符串日期与传入的有效内容日期格式相同？