C# 使用 HttpClient 从 JSON 响应中获取特定对象

Question

我正在尝试从 google maps api 解析 json 以进行地理编码。

JSON 是:

{
"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" : 37.4224277,
           "lng" : -122.0843288
        },
        "location_type" : "ROOFTOP",
        "viewport" : {
           "northeast" : {
              "lat" : 37.4237766802915,
              "lng" : -122.0829798197085
           },
           "southwest" : {
              "lat" : 37.4210787197085,
              "lng" : -122.0856777802915
           }
        }
     },
     "place_id" : "ChIJ2eUgeAK6j4ARbn5u_wAGqWA",
     "types" : [ "street_address" ]
  }
 ],
"status" : "OK"
}

我只对具有纬度和经度的 location 对象感兴趣，并且想知道如何在 c# 中导航 json 对象树以从 HttpContent 中检索它们作为 GetAsync 的响应一个 HttpClient。以下代码片段说明了我的请求是如何完成的。

public async Task<Coordinates> GeoCode(string address) 
{
      HttpClient client= new HttpClient();
      var baseUrl = "http://maps.google.com/maps/api/geocode/json?address=";
      var addressEncoded = WebUtility.UrlEncode(address);
      var response= await client.GetAsync(baseUrl + addressEncoded);

      if(response.IsSuccessStatusCode)
      {
           //read location ...
      }
}

我如何读取位置对象？

Answer 1

这是我通常的做法。 (我把你的json对象保存到D:/json.txt)

 var json = File.ReadAllText("D:/json.txt");
 var results = JObject.Parse(json).SelectToken("results") as JArray;

foreach (var result in results)
{
    var geometryEntry = result.SelectToken("geometry.location");
    var longitude = geometryEntry.Value<double>("lat");
    var latitude = geometryEntry.Value<double>("lng");

    Console.WriteLine("{0}, {1}", longitude, latitude);
}

输出: