Deserialize with Newtonsoft.Json

Question

I'm a tester learning C# and REST service testing both new to me...... I have a JSON response like this

{ "results" : [
    {
        "address_components" : [
        {
            "long_name" : "1600",
            "short_name" : "1600",
            "types" : [ "street_number" ]
        },
        {
            "long_name" : "Amphitheatre Parkway",
            "short_name" : "Amphitheatre Pkwy",
            "types" : [ "route" ]
        },
        {
            "long_name" : "Mountain View",
            "short_name" : "Mountain View",
            "types" : [ "locality", "political" ]
        },
        {
            "long_name" : "Santa Clara County",
            "short_name" : "Santa Clara County",
            "types" : [ "administrative_area_level_2", "political" ]
        },
        {
            "long_name" : "California",
            "short_name" : "CA",
            "types" : [ "administrative_area_level_1", "political" ]
        },
        {
            "long_name" : "United States",
            "short_name" : "US",
            "types" : [ "country", "political" ]
        },
        {
            "long_name" : "94043",
            "short_name" : "94043",
            "types" : [ "postal_code" ]
        }
     ],
     "formatted_address" : "1600 Amphitheatre Pkwy, Mountain View, CA 94043, USA",
     "geometry" : {
        "location" : {
           "lat" : 37.4223434,
           "lng" : -122.0843689
        },
        "location_type" : "ROOFTOP",
        "viewport" : {
           "northeast" : {
              "lat" : 37.42369238029149,
              "lng" : -122.0830199197085
           },
           "southwest" : {
              "lat" : 37.42099441970849,
              "lng" : -122.0857178802915
           }
        }
     },
     "place_id" : "ChIJ2eUgeAK6j4ARbn5u_wAGqWA",
     "types" : [ "street_address" ]
  }
],
"status" : "OK"
} 

and going to deserialize it to object and only need "lat" and "lng" in geometry / location

My code look like

JObject myMap = JObject.Parse(response.Content);
IList<JToken> mylist = myMap["results"][0]["geometry"].Children().ToList();`

 IList<location> spots = new List<location>();
foreach (JToken spot in mylist)
{
    Console.WriteLine("\nthe spots are :\t:"+ spot.ToString());
    location somesopt = JsonConvert.DeserializeObject<location>(spot.ToString());
    Console.WriteLine("\n the lat is :\t" + somesopt.lat.ToString());
    Console.WriteLine("\n the lat is :\t" + somesopt.lng.ToString());
}

and my objects are .........

   public class location
{
    public double lat { get; set; }
    public double lng { get; set; }
}

public class geopost
{
    public location geometry;
}

The problem is always I get JsonSerializationException at json deseserializobject I try changing many permutation of defining mylist but could not get it write ....what wrong am I doing..?

when use same structure of code for "Long_name" and "short_name" at address component it works fine. I understand that address component is array and geometry / location are objects. But how do you handle it?

Answer 1

I do the same as sugested by DavidG, but I generate the clases by copying the JSON into the clipboard and then on VS I go to menú Edit->Paste Special->Paste JSON as Classes.

That generates the classes needed to deseralize:

public class Rootobject
{
    public Result[] results { get; set; }
    public string status { get; set; }
}

public class Result
{
    public Address_Components[] address_components { get; set; }
    public string formatted_address { get; set; }
    public Geometry geometry { get; set; }
    public string place_id { get; set; }
    public string[] types { get; set; }
}

(...)

And same deserialization approach:

var data = JsonConvert.DeserializeObject<RootObject>(json);

Answer 2

Why not deserialise to a proper class structure? Something like this:

public class AddressComponent
{
    public string long_name { get; set; }
    public string short_name { get; set; }
    public List<string> types { get; set; }
}

public class Location
{
    public double lat { get; set; }
    public double lng { get; set; }
}

public class Northeast
{
    public double lat { get; set; }
    public double lng { get; set; }
}

public class Southwest
{
    public double lat { get; set; }
    public double lng { get; set; }
}

public class Viewport
{
    public Northeast northeast { get; set; }
    public Southwest southwest { get; set; }
}

public class Geometry
{
    public Location location { get; set; }
    public string location_type { get; set; }
    public Viewport viewport { get; set; }
}

public class Result
{
    public List<AddressComponent> address_components { get; set; }
    public string formatted_address { get; set; }
    public Geometry geometry { get; set; }
    public string place_id { get; set; }
    public List<string> types { get; set; }
}

public class RootObject
{
    public List<Result> results { get; set; }
    public string status { get; set; }
}

Then deserialise like this:

var data = JsonConvert.DeserializeObject<RootObject>(json);

Now you can operate directly on your object hierarchy:

foreach (var result in data.results)
{
    var lat = result.geometry.location.lat;
}

PS I generated the class hierarchy from json2csharp.com