无法以异步方法返回结果

Question

In an MVVM pattern I'm trying to make an async method that fetches a json string, and returns the result as a List<Cabinet> so that I can use this list later.

I have json that looks like this, it represents a list of cabinet object:

{"cabinets":[{"id":"1","longitudeGPS":"2,2891506","latitudeGPS":"48,8618687","cp":"75016","ville":"Paris","rue":"1 Avenue Gustave V de Su\u00e8de"},{"id":"2","longitudeGPS":"3,0566481","latitudeGPS":"50,6302592","cp":"59800","ville":"Lille","rue":"127 Rue Solf\u00e9rino"},{"id":"3","longitudeGPS":"3,8749271","latitudeGPS":"43,6110374","cp":"34000","ville":"Montpellier","rue":"17 Rue Foch"},{"id":"4","longitudeGPS":"-1,6736931","latitudeGPS":"48,1181043","cp":"35700","ville":"Rennes","rue":"127 23 Rue de Vincennes"},{"id":"5","longitudeGPS":"0,0991065","latitudeGPS":"49,4931952","cp":"76600","ville":"Le Havre","rue":"32 Avenue Foch"},{"id":"6","longitudeGPS":"4,8353320","latitudeGPS":"45,7639021","cp":"69002","ville":"Lyon","rue":"27 Rue Henri Germain"}]}

I've created the classes according to json2csharp generator:

public class Cabinet
{
    public string id { get; set; }
    public string longitudeGPS { get; set; }
    public string latitudeGPS { get; set; }
    public string cp { get; set; }
    public string ville { get; set; }
    public string rue { get; set; }
}

public class CabinetList
{
    public List<Cabinet> cabinets { get; set; }
}

Here I have an HttpClient that fetches the jso n from the website and stores it in a listCabinet variable.

public string adresseCabinets = "http://ppe3JoJuAd/gsbAppliFraisV2/webservices/w_cabinet.php";
public static string userId;

CabinetsList listeCabinets = new CabinetsList();
public async Task<List<CabinetsList>>loadCabinets()
{
    HttpClient clientCabinets = new HttpClient();
    var response = await clientCabinets.GetAsync(adresseCabinets);
    var json = response.Content.ReadAsStringAsync().Result;
    listeCabinets = JsonConvert.DeserializeObject<CabinetsList>(json);
}

When I want to return the listeCabinets variable I have the following error: cannot implicitly convert type cabinetList to System.Collection.Generic.List CabinetList

How can I solve this?

Answer 1

The return type of your method is List<CabinetsList> , while the output of DeserializeObject<CabinetsList> is a CabinetsList . You should deserialize the JSON as the type you want to return:

return JsonConvert.DeserializeObject<List<CabinetsList>>(json);

Or create a new list to add the one and only cabinet to if the JSON contains just one:

return new List<CabinetsList> { JsonConvert.DeserializeObject<CabinetsList>(json) };

Side note: and of course await the result:

var json = await response.Content.ReadAsStringAsync();