Get problem when deserialize JSON with GetFromJsonAsync

Question

I want to deserialize JSON objects by using GetFromJsonAsync in C#. Easily, values are extracted from JSON, but the problem is sub object values are not being extracted.

For testing, I'm using Open Meteo API. (example API link: https://api.open-meteo.com/v1/forecast?latitude=38.48&longitude=27.24&current_weather=true)

With my code I get, latitude, longitude, etc. (first part). But, I can't get temperature, windspeed, etc at current_weather sub structure.

Sample JSON values:

{
  "latitude": 38.4375,
  "longitude": 27.25,
  "generationtime_ms": 0.21195411682128906,
  "utc_offset_seconds": 0,
  "timezone": "GMT",
  "timezone_abbreviation": "GMT",
  "elevation": 137,
  "current_weather": {
    "temperature": 12.3,
    "windspeed": 6.4,
    "winddirection": 137,
    "weathercode": 3,
    "time": "2023-02-26T06:00"
  }
}

Latitude and Longitude are OK, but the Temperature always returns zero.

Do you have any idea?

My code is as follows:

using System.Net.Http.Json;
using System.Runtime.ConstrainedExecution;

namespace HttpClientExtensionMethods
{
    public class City
    {
        public float Latitude { get; set; }
        public float Longitude { get; set; }
        public float Temperature { get; set; }
    }
        
    public class Program
    {
        public static async Task Main()
        {
            using HttpClient client = new()
            {
                BaseAddress = new Uri("https://api.open-meteo.com/v1/forecast?latitude=52.52&longitude=13.41&current_weather=true")
            };

            // Get Json Weather information.
            City? city = await client.GetFromJsonAsync<City>("");
          
            Console.WriteLine($"Latitude: {city?.Latitude}");
            Console.WriteLine($"Longitude: {city?.Longitude}");
            Console.WriteLine($"Temperature: {city?.Temperature}");
        }
    }
}

I have tried creating an additional public class for current_weather, but with no success. I want to reach sub-values under the current_weather structure.

Answer 1

The weather field is in the nested object of current_weather field. Use tools such as Json2Csharp or Visual Studio to convert the JSON string into classes.

Your classes for the JSON response should be as below:

using System.Text.Json.Serialization;

public class City
{
    public float Latitude { get; set; }

    public float Longitude { get; set; }

    [JsonPropertyName("current_weather")]
    public CurrentWeather CurrentWeather { get; set; }
}

public class CurrentWeather
{
    [JsonPropertyName("temperature")]
    public double Temperature { get; set; }

    [JsonPropertyName("windspeed")]
    public double Windspeed { get; set; }

    [JsonPropertyName("winddirection")]
    public double Winddirection { get; set; }

    [JsonPropertyName("weathercode")]
    public int Weathercode { get; set; }

    [JsonPropertyName("time")]
    public string Time { get; set; }
}