Newtonsoft JSON deserialize using HttpWebResponse

Question

I was searching in all the questions about deserialization with Newtonsfot Json Converter. But i wasn't able to find the problem in my code. So I put here, asking for help.

The message error from the visual studio:

No se controló Newtonsoft.Json.JsonSerializationException HResult=-2146233088 Message=Cannot deserialize the current JSON array (e.g. [1,2,3]) into type 'APIEffilogics.Usuari+Client' because the type requires a JSON object (e.g. {"name":"value"}) to deserialize correctly. To fix this error either change the JSON to a JSON object (e.g. {"name":"value"}) or change the deserialized type to an array or a type that implements a collection interface (e.g. ICollection, IList) like List that can be deserialized from a JSON array. JsonArrayAttribute can also be added to the type to force it to deserialize from a JSON array.

My JSON response is like this:

[  {
  "id": 32,
  "consultancy_id": 1,
  "nif": "B61053922",
  "contactname": "",
  "email": "",
  "phone": "",
  "active": true,
  "description": "Keylab"   },   
{
  "id": 19,
  "consultancy_id": 1,
  "nif": "P0818300F",
  "contactname": "Pau Lloret",
  "email": "lloret@citcea.upc.edu",
  "phone": "",
  "active": true,
  "description": "Rubi"   } ]

And those are the classes:

namespace APIEffilogics
{
    public class Usuari
    {
        public string access_token;    //Encapsulat que conté la identificació de seguretat
        public string token_type;      //Tipus de token, "Bearer"
        public string response;        //Resposta de l'API

        public class Client : Usuari    //Estructura client
        {
            [JsonProperty("id")]
            public string cid { get; set; }
            [JsonProperty("consultancy_id")]
            public string consultancy_id { get; set; }
            [JsonProperty("contactname")]
            public string contactname { get; set; }
            [JsonProperty("email")]
            public string email { get; set; }
            [JsonProperty("description")]
            public string description { get; set; }
            [JsonProperty("nif")]
            public string nif { get; set; }
            [JsonProperty("phone")]
            public string phone { get; set; }
            [JsonProperty("active")]
            public string active { get; set; }
        }
        public class Building : Usuari  //Estructura edifici
        {
            public string descrip;
            public string bid;
        }
        public class Floor : Usuari     //Estructura planta
        {
            public string descrip;
            public string fid;
        }
        public class Room : Usuari      //Estructura habitació
        {
            public string descrip;
            public string rid;
        }
        public class Node : Usuari      //Estructura nodes
        {
            public string[] descrip;
            public string[] nid;
            public string[] model;
            public string[] type;
        }
    }
 //************************END PUBLIC CLASS Usuari***************************//
}

The code that I use:

public void Request(string url, string metode)
{
   try
   {
      //Enviem la petició a la URL especificada i configurem el tipus de connexió
      HttpWebRequest myReq = (HttpWebRequest)WebRequest.Create(url);

      myReq.KeepAlive = true;
      myReq.Headers.Set("Cache-Control", "no-store");
      myReq.Headers.Set("Pragma", "no-cache");
      myReq.Headers.Set("Authorization", usuari.token_type + " " + usuari.access_token);

      if (metode.Equals("GET") || metode.Equals("POST"))
      {
           myReq.Method = metode;  // Set the Method property of the request to POST or GET.
           if (body == true)
           {
               // add request body with chat search filters
              List<paramet> p = new List<paramet>();
              paramet p1 = new paramet();
              p1.value = "1";
              string jsonBody = JsonConvert.SerializeObject(p1);
              var requestBody = Encoding.UTF8.GetBytes(jsonBody);
              myReq.ContentLength = requestBody.Length;
              myReq.ContentType = "application/json";
              using (var stream = myReq.GetRequestStream())
              {
                  stream.Write(requestBody, 0, requestBody.Length);
              }
              body = false;
           }
      }
      else throw new Exception("Invalid Method Type");

      //Obtenim la resposta del servidor
      HttpWebResponse myResponse = (HttpWebResponse)myReq.GetResponse();
      Stream rebut = myResponse.GetResponseStream();
      StreamReader readStream = new StreamReader(rebut, Encoding.UTF8); // Pipes the stream to a higher level stream reader with the required encoding format. 
      string info = readStream.ReadToEnd();
      var jsondata = JsonConvert.DeserializeObject<Usuari.Client>(info);

       myResponse.Close();
       readStream.Close();*/
    }
    catch (WebException ex)
    {
       // same as normal response, get error response
       var errorResponse = (HttpWebResponse)ex.Response;
       string errorResponseJson;
       var statusCode = errorResponse.StatusCode;
       var errorIdFromHeader = errorResponse.GetResponseHeader("Error-Id");
       using (var responseStream = new StreamReader(errorResponse.GetResponseStream()))
       {
           errorResponseJson = responseStream.ReadToEnd();
       }
     }
}

I don't know where is the problem, the response have the correct JSON scheme. Somebody can explain me where is the problem in my code, or if I'm not doing correctly.

I've solved the problem how you say, nut now I've a similar problem and the same message error. The JSON response now is this: {

    nodes: [
      {
        id: 5,
        global_id: 5,
        description: "Oven",
        room_id: 2,
        floor_id: 1,
        building_id: 1,
        client_id: 2,
        nodemodel_id: 2,
        nodetype_id: 1
      },
      {
        id: 39,
        global_id: 39,
        description: "Fridge",
        room_id: 2,
        floor_id: 1,
        building_id: 1,
        client_id: 2,
        nodemodel_id: 8,
        nodetype_id: 1
      }, ...
    ],
    limit: 10,
    offset: 0
}

And those are the classes:

public class Node : Usuari      //Estructura nodes
{            
   [JsonProperty("limit")]
   public int limit { get; set; }
   [JsonProperty("offset")]
   public int offset { get; set; }
   [JsonProperty("nodes")]
   public List<Node_sub> nodes_sub { get; set; }
}
public class Node_sub : Node
{
    [JsonProperty("id")]
    public string nid { get; set; }
    [JsonProperty("global_id")]
    public string gid { get; set; }
    [JsonProperty("description")]
    public string descrip { get; set; }
    [JsonProperty("room_id")]
    public string rid { get; set; }
    [JsonProperty("floor_id")]
    public string fid { get; set; }
    [JsonProperty("client_id")]
    public string cid { get; set; }
    [JsonProperty("building_id")]
    public string bid { get; set; }
    [JsonProperty("nodemodel_id")]
    public string model { get; set; }
    [JsonProperty("nodetype_id")]
    public string type { get; set; }
}

The code is the same as before, only I add this sentences:

jsonnode = JsonConvert.DeserializeObject<List<Usuari.Node>>(info);

Why I'm having the same error? List<Usuari.Node> is an array that contains all the items of JSON message.

Thanks

Answer 1

Try

var jsondata = JsonConvert.DeserializeObject<List<Usuari.Client>>(info);

This addresses the issue as the exception suggests:

To fix this error either change the JSON to a JSON object (e.g. {"name":"value"}) or change the deserialized type to an array or a type that implements a collection interface (e.g. ICollection, IList) like List that can be deserialized from a JSON array

Emphasis added to highlight the salient point

The HTTP response you receive is an array of objects so you need to deserialise it in a way that can deal with an array of objects. By changing your code to deserialise into a List<Usari.Client> you do just that and it should resolve the error.