在字典中向下遍历键以从已知键中获取值

我有一个看起来像这样的Dictionary<string, object> testJson：

{
  "Data": {
    "Request": {
      "Id": "ADLFKJ9LKJADFJLSKLDJFAS",
      "Ts": "Fri Apr 04 10:51:54 EDT 2014",
      "Parameters": "advertisers=&responseFormat=json"
    },
    "Response": {
      "Id": null,
      "Ts": null
    },
    "StatusCode": "09",
    "Message": "Processing."
  }
}

我需要获取 Data ==> Request ==> Id 和 Data ==> StatusCode 和 Data ==> Message 的值。

到目前为止，我已经

var requestId = (from p in testJson
                             where p.Key.Contains("Id")
                             select p.Value)
                             .FirstOrDefault();
Console.WriteLine(requestId.ToString());

它似乎没有按照我预期的方式工作... requestId正在返回null.

谢谢。

var data = (Dictionary<string, object>)testJson["Data"];
var request = (Dictionary<string, object>)testJson["Request"];
var message = (string)data["Message"];
var status code = (string)data["StatusCode"];
var id = (string)request["Id"];