ASP.NET Framework调用API绑定GridView报Newtonsoft.Json序列化错误如何解决

问题背景 #

使用ASP.NET Framework开发时，通过HttpClient调用API接口获取成员列表数据，计划将返回数据绑定到GridView控件，接口返回示例JSON如下：

{
  "success": true,
  "status": 200,
  "data": [
    {
      "ProfileID": "1001",
      "Name": "Jane Doe",
      "HomePhone": "555-1212",
      "Address1": "123 Elm St"
    },
    {
      "ProfileID": "1002",
      "Name": "Rick Fox",
      "HomePhone": "555-1213",
      "Address1": "123 Ok St"
    }
  ]
}

初始代码与报错信息 #

初始编写的绑定逻辑代码如下：

using Newtonsoft.Json;

private void popGrid()
{
   var client = new HttpClient();
   client.BaseAddress = new Uri("http://the-api/");
   var responseTask = client.GetAsync("member-list");
   responseTask.Wait();
   var result = responseTask.Result;
   if (result.IsSuccessStatusCode)
   {
      var read_response = responseTask.Result.Content.ReadAsStringAsync();
      read_response.Wait();
      var read_result = read_response.Result;

      dynamic response = JsonConvert.DeserializeObject(read_result);
      var success = response.success;
      var status = response.status;
      var data = response.data;

      // List<Root> myDeserializedClass = JsonConvert.DeserializeObject<List<Root>>(data);

      if ((bool)success)
      {
         GridView1.DataSource = data;
         GridView1.DataBind();
      }
   }

}

public class Root
{
   public string ProfileID { get; set; }
   public string Name { get; set; }
   public string HomePhone { get; set; }
   public string Address1 { get; set; }
}

代码执行全程无异常，但页面渲染阶段抛出如下错误：

Type 'Newtonsoft.Json.Linq.JValue' in Assembly 'Newtonsoft.Json, Version=13.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed' is not marked as serializable.

堆栈跟踪关键报错线索：

[ArgumentException: Error serializing value '1001' of type 'Newtonsoft.Json.Linq.JValue.']

后续尝试取消注释强类型反序列化代码行，又抛出如下参数不匹配错误：

Microsoft.CSharp.RuntimeBinder.RuntimeBinderException: 'The best overloaded method match for 'Newtonsoft.Json.JsonConvert.DeserializeObject<System.Collections.Generic.List<Root>>(string)' has some invalid arguments'

问题根因 #

• 首次报错：直接绑定dynamic反序列化得到的JArray对象作为数据源时，数组内对象的属性值都是Newtonsoft.Json.Linq.JValue类型，该类型未标记可序列化特性，GridView在渲染序列化数据源时就会抛出异常。
• 二次报错：JsonConvert.DeserializeObject<T>()方法要求入参是原始JSON字符串，但代码中传入的data是已经解析完成的JToken对象，类型不匹配导致运行时绑定错误。

最终可运行实现 #

通过将API返回的data节点直接转换为DataTable作为GridView数据源，不需要额外做类型映射即可适配WebForm控件的序列化要求，调整后的完整代码如下：

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

const string theAPI = "http://the-api/";
const string otherAPI = "http://other-api/";

protected void Button2_Click(object sender, EventArgs e)
{
   DataTable dt = GetDataTableFromAPI(theAPI, "member-list");
   if (dt.Rows.Count > 0)
   {
      GridView1.DataSource = dt;
      GridView1.DataBind();
      GridView1.HeaderRow.TableSection = TableRowSection.TableHeader;
   }
   else
   {
      // 无匹配数据处理逻辑
   }
}

public DataTable GetDataTableFromAPI(string api, string endPoint) 
{
   var client = new HttpClient();
   client.BaseAddress = new Uri(api);
   var response = client.GetAsync(endPoint).Result;
   if (response.IsSuccessStatusCode)
   {
      var json = response.Content.ReadAsStringAsync().Result;
      var jsonParsed = JObject.Parse(json);
      var success = jsonParsed["success"];
      var status = jsonParsed["status"];
      if ((bool)success)
      {
         DataTable dt = jsonParsed["data"].ToObject<DataTable>();
         return dt;
      }
   }
   return new DataTable();
}

内容的提问来源于stack exchange，提问作者JonV