如何从C＃ASP.NET中的JSON字符串中仅解析纬度和经度信息？

Question

I've looked everywhere and can't find a solution that works for me with this problem.

I'm using the Google Maps API and need to take an address, convert it to latitude/longitude, and then generate my map with those values.

I'm using NewtonSoft.Json to try and deserialize my string but am getting different errors for every method I try.

Here is how I'm accessing my JSON:

var webClient = new WebClient();
var json = webClient.DownloadString(@"https://maps.googleapis.com/maps/api/geocode/json?address=1600%20Pennsylvania%20Ave%20NW,%20Washington,%20DC%2020500&key=AIzaSyAKORLziVDRpaIlRs7NrPwGsye9NNn6Mdw");

Right now I'm only using a static address for debugging purposes, but will be switching to variables later.

Here is the URL to see the JSON:

I know that this is imported correctly because I'm using System.Diagnostics.Debug.WriteLine("json "+json); to check and debug.

I've also confirmed with https://jsonlint.com/ that it is valid JSON.

So now, I need to deserialize this String to grab

  "location" : { "lat" : 38.8976633, "lng" : -77.03657389999999 

and save them into variables for later access.

I would like to do this without making an entire class, but if that's what needs to be done I can manage.

Can anyone help me format the JsonConvert.DeserializeObject() command to work for this?

Answer 1

You can use JSON.net to deserialize partial JSON fragments here is an example to what you are trying to achieve, and this is the code for your case.

 var webClient = new WebClient();
 string json = webClient.DownloadString(@"https://maps.googleapis.com/maps/api/geocode/json?address=1600%20Pennsylvania%20Ave%20NW,%20Washington,%20DC%2020500&key=AIzaSyAKORLziVDRpaIlRs7NrPwGsye9NNn6Mdw");
 JObject jsonOb = JObject.Parse(json);
 double lat  = jsonOb["results"]["geometry"]["location"]["lat"];
 double lng  = jsonOb["results"]["geometry"]["location"]["lng"];

Answer 2

First of all you need to define c# classes to your json. It is not manual work. Copy all json to clipboard. Then go to Visual Studio, open create new .cs file with class, and then Edit->Paster special->Paste JSON as Classes . In your case it will be these classes

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; }
}

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

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

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

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

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

public class Viewport
{
    public Northeast1 northeast { get; set; }
    public Southwest1 southwest { get; set; }
}

public class Northeast1
{
    public float lat { get; set; }
    public float lng { get; set; }
}

public class Southwest1
{
    public float lat { get; set; }
    public float lng { get; set; }
}

public class Address_Components
{
    public string long_name { get; set; }
    public string short_name { get; set; }
    public string[] types { get; set; }
}

Then you can desesrialize it based on this classes

 var webClient = new WebClient();
 var json = webClient.DownloadString(@"https://maps.googleapis.com/maps/api/geocode/json?address=1600%20Pennsylvania%20Ave%20NW,%20Washington,%20DC%2020500&key=AIzaSyAKORLziVDRpaIlRs7NrPwGsye9NNn6Mdw");
 var parsedObj = JsonConvert.DeserializeObject<Rootobject>(json);
 var location = parsedObj.results?[0].geometry?.location;
 Console.WriteLine(location.lat);
 Console.WriteLine(location.lng);

Answer 3

It would be best to make an object to cast the JSON into. But you could use untyped objects.

var outputObject = JsonConvert.DeserializeObject(JsonString)

when you make an object for the convert to cast to, you do the following:

Type outputObject = JsonConvert.DeserializeObject<Type>(jsonstring);

Answer 4

This worked for me

var webClient = new WebClient();
var json = webClient.DownloadString(@"https://maps.googleapis.com/maps/api/geocode/json?address=1600%20Pennsylvania%20Ave%20NW,%20Washington,%20DC%2020500&key=AIzaSyAKORLziVDRpaIlRs7NrPwGsye9NNn6Mdw");
var obj = JsonConvert.DeserializeObject<dynamic>(json);
Console.WriteLine(obj.results[0].geometry.bounds.northeast.lat.Value);