Deserialize Zomato JSON response in C#

Question

I am using Zomato API and I am receiving the following JSON response :

{
"categories": [
    {
      "categories": {
        "id": 1,
        "name": "Delivery"
      }
    },
    {
      "categories": {
        "id": 2,
        "name": "Dine-out"
      }
    },
    {
      "categories": {
        "id": 3,
        "name": "Nightlife"
      }
    },
    {
      "categories": {
        "id": 4,
        "name": "Catching-up"
      }
    },
    {
      "categories": {
        "id": 5,
        "name": "Takeaway"
      }
    },
    {
      "categories": {
        "id": 6,
        "name": "Cafes"
      }
    },
    {
      "categories": {
        "id": 7,
        "name": "Daily Menus"
      }
    },
    {
      "categories": {
        "id": 8,
        "name": "Breakfast"
      }
    },
    {
      "categories": {
        "id": 9,
        "name": "Lunch"
      }
    },
    {
      "categories": {
        "id": 10,
        "name": "Dinner"
      }
    },
    {
      "categories": {
        "id": 11,
        "name": "Pubs & Bars"
      }
    },
    {
      "categories": {
        "id": 13,
        "name": "Pocket Friendly Delivery"
      }
    },
    {
      "categories": {
        "id": 14,
        "name": "Clubs & Lounges"
      }
    }
  ]
}

I want to deserialize this response and I created the following classes :

public class CategoriesTop
{
    public List<CategoriesBottom> categories { get; set; }
}
public class CategoriesBottom
{
    public Categorie categorie { get; set; }
}
public class Categorie
{
    public int id { get; set; }
    public string name { get; set; }
}

And I am using this code to get the response :

public Form1()
    {
        InitializeComponent();

        HttpWebRequest webRequest =
                WebRequest.Create("https://developers.zomato.com/api/v2.1/categories")
                        as HttpWebRequest;
        HttpWebResponse webResponse = null;
        webRequest.Headers.Add("X-Zomato-API-Key", "509ce9e4863960cdc076fb3817cc238e");
        //you can get KeyValue by registering with Zomato.
        webRequest.Method = "GET";
        webResponse = (HttpWebResponse)webRequest.GetResponse();
        if (webResponse.StatusCode == HttpStatusCode.OK)
        {
            StreamReader responseReader = new
                               StreamReader(webResponse.GetResponseStream());
            string responseData = responseReader.ReadToEnd();
            //XmlDocument doc = new XmlDocument();
            //doc.LoadXml(responseData);
            //XmlNodeReader xmlReader = new XmlNodeReader(doc);
            //DataSet ds = new DataSet();
            //ds.ReadXml(xmlReader);
            List<CategoriesBottom> l = JsonConvert.DeserializeObject<List<CategoriesBottom>>(responseData);
            foreach(CategoriesBottom c in l)
            {
                cmbCatName.Items.Add(c.categorie.name);
            }
        }
    }

When I run the program I receive an error on the JSON.Convert line :

Newtonsoft.Json.JsonSerializationException: 'Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List`1[WindowsFormsApp1.CategoriesBottom]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.

So I think I have a problem with the deserialize code or the classes are defined incorrectly. Any help will be appreciated.

Answer 1

Try to change the property to to match the json data:

public class CategoriesBottom
{
    public Categorie categories { get; set; }
}

Also serialize your CategoriesTop type:

CategoriesTop ct = JsonConvert.DeserializeObject<CategoriesTop>(responseData);

Answer 2

The easiest way to generate C# classes for JSON structures is via json2csharp on-line service.

The first problem is that your property in CategoriesBottom is called categorie while the structure contains categories

public class CategoriesBottom
{
    [JsonProperty( "categories" )]
    public Categorie categorie { get; set; }
}

Also you deserialize a List<CategoriesBottom> which is not working, because the whole list is wrapped in another object (CategoriesTop). So you rather should do the following:

JsonConvert.DeserializeObject<CategoriesTop>(responseData);

Answer 3

Use RestSharp for getting the data from other source. RestSharp has a great feature to deserialize response to class.

This is the example from the RestSharp wiki:

 IRestResponse<Person> response2 = client.Execute<Person>(request);
 var name = response2.Data.Name;

With that you already got the result. Please check the documentation for further information. You can directly install this package using nuget and start to use it.