从JSON响应中检索元素

我试图从我们正在构建的Web API中的rest服务的响应中获得一个字段。JSON如下所示:

{
"d": {
    "results": [{
        "__metadata": {
            "id": "Web/Lists(guid'4ddc-41e2-bb44-0f92ad2c0b07')/Items(164)",
            "uri": "https://teams.ax.org/sites/js/project/_api/Web/Lists(guid'4ddc-41e2-bb44-0f92ad2c0b07')/Items(164)",
            "etag": "\"6\"",
            "type": "SP.Data.St_x0020_CdsListItem"
        },
        "Folder": {
            "__deferred": {
                "uri": "https://teams.ax.org/sites/js/project/_api/Web/Lists(guid'4ddc-41e2-bb44-0f92ad2c0b07')/Items(164)/Folder"
            }
        },
        "ParentList": {
            "__deferred": {
                "uri": "https://teams.ax.org/sites/js/project/_api/Web/Lists(guid'4ddc-41e2-bb44-0f92ad2c0b07')/Items(164)/ParentList"
            }
        },
        "PM_x0020_NameId": 220,
        "St_x0020_Name": "<div class=\"ExternalClassA14DB0FF86994403B827D91158CF34B0\">KO</div>",
    }]
}}

我创建了这些模型类:

 public class SharepointDTO
 {
    public class Metadata
    {
        [JsonProperty("id")]
        public string id { get; set; }

        [JsonProperty("uri")]
        public string uri { get; set; }

        [JsonProperty("etag")]
        public string etag { get; set; }

        [JsonProperty("type")]
        public string type { get; set; }
    }

    public class Deferred
    {
        [JsonProperty("uri")]
        public string uri { get; set; }
    }

    public class Folder
    {
        [JsonProperty("__deferred")]
        public Deferred __deferred { get; set; }
    }

    public class ParentList
    {
        [JsonProperty("__deferred")]
        public Deferred __deferred { get; set; }
    }

    public class Result
    {
        [JsonProperty("__metadata")]
        public Metadata __metadata { get; set; }

        [JsonProperty("Folder")]
        public Folder Folder { get; set; }

        [JsonProperty("ParentList")]
        public ParentList ParentList { get; set; }

        [JsonProperty("PM_x0020_NameId")]
        public int PM_x0020_NameId { get; set; }

        [JsonProperty("St_x0020_Name")]
        public string St_x0020_Name { get; set; }
    }

    public class D
    {
        [JsonProperty("results")]
        public IList<Result> results { get; set; }
    }

    public class RootObject
    {
        [JsonProperty("d")]
        public D d { get; set; }
    }
}

不需要尝试从Web API调用rest服务,需要从响应中获取St\u x0020\u名称并存储在字符串中。

  SharepointDTO.RootObject retSharepointobj = await GetfromSharepoint(StNumber);
  string StName = retSharepointobj.d.results.St_x0020_Name.ToString();

我正在反序列化 GetfromSharepoint 类似方法

using (var client_sharePoint = new HttpClient(handler))
{
    var response = client_sharePoint.GetAsync(SP_URL).Result;

    var responsedata = await response.Content.ReadAsStringAsync();
    var returnObj = JsonConvert.DeserializeObject<SharepointDTO.RootObject>(responsedata);

    return returnObj;
}

但它抛出了一个错误:

'系统。收藏。通用的“IList”不包含“St\u x0020\u Name”的定义,并且没有扩展方法“St\u x0020\u Name”接受“System”类型的第一个参数。收藏。通用的可以找到IList(您是否缺少using指令或程序集引用?)