How to pass values from service to ViewModel? - mvvm

Question

I created service to get data from JSON file and now I'm trying to show them on page.
In service, variable model get correct values, but in ViewModel varibales as StationId, StationName, Message, DateText etc are null, so obvious nothing is showing on page.
(Currently I set some hardcoded values for test purpose)
Model
public class IrrigNetModel
{
public IrrigNetModelItem[] items { get; set; }
}
public class IrrigNetModelItem
{
public int ID { get; set; }
public string Message { get; set; }
public DateTime Date { get; set; }
public string DateText { get; set; }
public int StationId { get; set; }
public string StationName { get; set; }
public float StationLongitude { get; set; }
public float StationLatitude { get; set; }
public int ServiceId { get; set; }
public string ServiceName { get; set; }
}
Service
class IrrigNetService
{
public static async Task<IrrigNetModel> GetServices(string token, string lngCode)
{
IrrigNetModel model = new IrrigNetModel();
try
{
string URL = DataURL.BASE_URL + "agronetmobile/getlistnotifications?lngCode=" + lngCode;
string content = Newtonsoft.Json.JsonConvert.SerializeObject(model);
using (var client = new HttpClient())
{
client.DefaultRequestHeaders.TryAddWithoutValidation("Content-Type", "application/json");
client.DefaultRequestHeaders.TryAddWithoutValidation("Authorization", token);
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
//client.DefaultRequestHeaders.TryAddWithoutValidation("Culture", LocalData.Lang);
HttpResponseMessage result = await client.PostAsync(URL, new StringContent(content, Encoding.UTF8, "application/json"));
if (result.StatusCode == System.Net.HttpStatusCode.OK)
{
string resultContent = await result.Content.ReadAsStringAsync();
model = (IrrigNetModel)Newtonsoft.Json.JsonConvert.DeserializeObject(resultContent, typeof(IrrigNetModel));
}
else if (result.StatusCode == System.Net.HttpStatusCode.Unauthorized)
{
//
}
}
}
catch (Exception ex)
{
model = null;
}
return model;
}
}
ViewModel:
public ObservableCollection<IrrigNetModelItem> IrrigNetCollection { get; set; } = new ObservableCollection<IrrigNetModelItem>
{
new IrrigNetModelItem
{
StationId = 1,
StationName = "Krakatosia",
Message = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur scelerisque a lorem sit amet mattis.",
DateText = "21.07.2012."
}
};
public IrrigNetViewModel()
{
var token = LocalData.Token;
IrrigNetService.GetServices(token,"sr");
TabTappedCommand = new Command((tabName) => OnTapClicked(tabName.ToString()));
HideListOnTapCommand = new Command(HideListOnTap);
IrrigNetModelItem model = new IrrigNetModelItem();
var irrigNetModel = new IrrigNetModelItem
{
StationId = model.StationId,
StationName = model.StationName,
Message = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Curabitur scelerisque a lorem sit amet mattis.",
DateText = model.DateText
};
IrrigNetCollection.Add(irrigNetModel);
}

Answer 1

you are calling the service but not storing the result
IrrigNetService.GetServices(token,"sr");
instead, try this
var data = await IrrigNetService.GetServices(token,"sr");
foreach (var d in data.items) {
IrrigNetCollection.Add(d);
}