CODEWITHSUNDEEP
c#jsonmultithreadingparsingobject
Ayohaych
Ayohaych

Reputation: 5189

C# Getting a JSON object

So I have a City class that I want to be able to get and store JSON data.

    public string status { get; set; }
    public string id { get; set; }
    public string country { get; set; }
    public string region { get; set; }
    public string mainCity { get; set; }
    public string latitude { get; set; }
    public string longitude { get; set; }
    public string comment { get; set; }
    public bool wasThereAnError { get; set; }

    public class CityResponse
    {
        public string status { get; set; }
        public string Message { get; set; }
        public List<City> result { get; set; }
    }

In my App I need to request a City by an ID or display a list of Cities by a country code so I want the City to be a base class.

Here is the code I am trying to use to make this happe. It is in a WebRetrieval class

    async private Task<City> GetCityInformation(string url)
    {
        var client = new HttpClient();
        var response = await client.GetAsync(new Uri(url));

        string result = await response.Content.ReadAsStringAsync();

        //var cityRootaaa = JsonConvert.DeserializeObject<City.CityResponse>(result);
        var cityRoot = JsonConvert.DeserializeObject<City>(result);
        return cityRoot;
}

    //Return City
    async public Task<City> GetCity(string url)
    {
        City city = await GetCityInformation(url);
        return city;
    }

And then when I try to make a City object in the City_Page class, I use this:

            long cityNum = Convert.ToInt64(CityID_Textbox.Text);
            string url = "http://honey.computing.dcu.ie/city/city.php?id=" + cityNum;


            City city = wr.GetCity(url);
            myTextBlock1.Text = city.ToString();

I keep getting erros about System.Threading.tasks.task not being able to be converted to CityApp.City.

I'm really stumped and I don't know what to do. Right now the code is broken and I have no idea how to fix it. So I would really appreciate any help with it. Thanks

Upvotes: 1

Views: 354

Answers (4)

Allan Elder
Allan Elder

Reputation: 4104

Change

City city = wr.GetCity(url);

to

City city = wr.GetCity(url).Result;

if you're using .Net 4.0; if you're using 4.5, then 

City city = await wr.GetCity(url);

Also, you're returning a CityResponse not just a City; the Json is failing to deserialize because it lacks [] to define the array. If you do the following

        var cityResponse = new CityResponse();
        cityResponse.status = "okay";
        cityResponse.result = new List<City>();
        var city = new City();
        city.Status = "0";
        city.Id = "1";
        city.Country = "2";
        city.Region = "3";
        city.MainCity = "4";
        city.Latitude = "5";
        city.Longitude = "6";
        city.Comment = "7";
        city.WasThereAnError = false;

        cityResponse.result.Add(city);

        var jsonString = JsonConvert.SerializeObject(cityResponse);

jsonString will be

"{\"status\":\"okay\",\"Message\":null,\"result\":[{\"Status\":\"0\",\"Id\":\"1\",\"Country\":\"2\",\"Region\":\"3\",\"MainCity\":\"4\",\"Latitude\":\"5\",\"Longitude\":\"6\",\"Comment\":\"7\",\"WasThereAnError\":false}]}"

Upvotes: 2

dcastro
dcastro

Reputation: 68740

To add to the other answers, you should delete your SerializeObject statement and simply deserialize the string into a City object.

    //result = JsonConvert.SerializeObject(response);

    var city = JsonConvert.DeserializeObject<City>(result);

Upvotes: 1

Frank Pfattheicher
Frank Pfattheicher

Reputation: 432

GetCity already awaits and should retung City instead of Task.

Upvotes: 1

Adam Maras
Adam Maras

Reputation: 26873

Your GetCity method is async, so you have to await it to get a City instead of a Task<City>.

City city = await wr.GetCity(url);

Upvotes: 1

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