ASP.net mvc API获取请求和JSON数据

Question

Trying to call a weather API using a service for asp.net mvc.

I have a Weather class that looks like this:

public class Weather
{
    public string main { get; set; }
    public string description { get; set; }
}

The method I am using to make the GET request looks like this:

    async public static Task<List<Weather>> GetWeather()
    {
        List<Weather> weatherData = new List<Weather>();

        HttpClient client = new HttpClient();
        HttpResponseMessage response = await client.GetAsync("http://api.openweathermap.org/data/2.5/weather?lat=35&lon=139&APPID=[MYKEY]");

        HttpContent content = response.Content;

        string data = await content.ReadAsStringAsync();
    }

The URI I'm requesting returns JSON objects.

{
  "coord": {
    "lon": 139,
    "lat": 35
  },
  "weather": [
    {
      "id": 804,
      "main": "Clouds",
      "description": "overcast clouds",
      "icon": "04n"
    }
  ],
  "base": "stations",
  "main": {
    "temp": 299.26,
    "pressure": 1007,
    "humidity": 83,
    "temp_min": 296.15,
    "temp_max": 301.15
  },
  "visibility": 16093,
  "wind": {
    "speed": 5.1,
    "deg": 330,
    "gust": 7.2
  },
  "clouds": {
    "all": 90
  },
  "dt": 1533638820,
  "sys": {
    "type": 1,
    "id": 7618,
    "message": 0.0028,
    "country": "JP",
    "sunrise": 1533585473,
    "sunset": 1533634868
  },
  "id": 1851632,
  "name": "Shuzenji",
  "cod": 200
}

I want to access the "weather" object and extract the properties main and description and in my GetWeather return a list where the weather properties from the JSON object match the properties in my class Weather .

I'm lost on what to do with the string data and how to get the JSON data into my List<Weather> .

EDIT

Tried to use JObject.Parse() as mentioned in the answer below but get an error Cannot perform runtime binding on a null reference when trying to print it to the console.

async public static Task<List<Weather>> GetWeather()
        {

            HttpClient client = new HttpClient();
            HttpResponseMessage response = await client.GetAsync("http://api.openweathermap.org/data/2.5/weather?lat=35&lon=139&APPID=[MYKEY]");

            HttpContent content = response.Content;

            string data = await content.ReadAsStringAsync();

            dynamic d = JObject.Parse(data);
            var main = d.main.ToString();
            var description = d.description.ToString();

            var weatherData = new List<Weather>
            {
                new Weather { Main = main,
                              Description = description }
            };

            Console.WriteLine(weatherData);

            return weatherData;
        }

Answer 1

Steps to access value of description from your json

Create model class for given json string, Visual studio provided option for it

Edit -> Paste special -> Paste JSON As class

class look like

public class MyClass
{
    public class Coord {
       public int lon { get; set; }
       public int lat { get; set; } }

    public class Weather {
       public int id { get; set; }
       public string main { get; set; }
       public string description { get; set; }
       public string icon { get; set; } }
 ...

Use NewtonSoft.JSON library to deserialize json

MyClass temp = JsonConvert.DeserializeObject<MyClass >(jsonString);

Now you can access description property of Weather class by

string output = temp.Weather.description

Answer 2

You want to look into deserializing the json. The easiest way for an example (although not as maintainable) would be to dump the json into a dynamic and pull the fields you want;

dynamic d = JObject.Parse(data);
var description = d.description.ToString();

If you create classes to match the JSON (it looks like your Weather class doesn't quite match - main is a nested object and not a string) then you can use Json.DeserializeObject< Weather >(data)