终于让我找到解决办法。使用Newtonsoft.Json这code作为样本进行动态数据结构：

Finally I found solution. Use Newtonsoft.Json and this code as sample for dynamic data structure:

$.ajax({
  ...
  data: {data: JSON.stringify({first: "name", next: ["a", "b"], last: {o: "in"}})}
})

    [HttpPost]
    public JsonResult SaveMenu(String data)
    {
       dynamic JData = JObject.Parse(data);
       //--now JData.first == "name"
       if (JData.last is JObject)
       {

       }

       //--or dynamic foreach
       foreach (dynamic own in JData)
       {
          //--own.Name == first, next and last
          //--access to variable == JData[own.Name]
          if (JData[own.Name] is JArray)
          {
              foreach (String var in JData[own.Name])
              {

              }
          }
       }
    }