Exception while tracking location in Windows Phone 8

Question

When I try to track location it works perfectly but when i add service reference to it it throws an exception when I try the same program without adding location only add service reference it works perfectly My code is here below while copy from How to continuously track the phone's location for Windows Phone 8

public partial class MainPage : PhoneApplicationPage
{

    Geolocator geolocator = null;
    bool tracking = false;
    ServiceReference2.GetPositionClient client = new ServiceReference2.GetPositionClient();
    // Constructor
    public MainPage()
    {
        InitializeComponent();

        // Sample code to localize the ApplicationBar
        //BuildLocalizedApplicationBar();
    }
    protected override void OnNavigatedTo(System.Windows.Navigation.NavigationEventArgs e)
    {
        if (IsolatedStorageSettings.ApplicationSettings.Contains("LocationConsent"))
        {
            // User has opted in or out of Location
            return;
        }
        else
        {
            MessageBoxResult result =
                MessageBox.Show("This app accesses your phone's location. Is that ok?",
                "Location",
                MessageBoxButton.OKCancel);

            if (result == MessageBoxResult.OK)
            {
                IsolatedStorageSettings.ApplicationSettings["LocationConsent"] = true;
            }
            else
            {
                IsolatedStorageSettings.ApplicationSettings["LocationConsent"] = false;
            }

            IsolatedStorageSettings.ApplicationSettings.Save();
        }
    }
    private void TrackLocation_Click(object sender, RoutedEventArgs e)
    {
        if ((bool)IsolatedStorageSettings.ApplicationSettings["LocationConsent"] != true)
        {
            // The user has opted out of Location.
            return;
        }

        if (!tracking)
        {
            geolocator = new Geolocator();
            geolocator.DesiredAccuracy = PositionAccuracy.High;
            geolocator.MovementThreshold = 100; // The units are meters.

            geolocator.StatusChanged += geolocator_StatusChanged;
            geolocator.PositionChanged += geolocator_PositionChanged;

            tracking = true;
            TrackLocationButton.Content = "stop tracking";
        }
        else
        {
            geolocator.PositionChanged -= geolocator_PositionChanged;
            geolocator.StatusChanged -= geolocator_StatusChanged;
            geolocator = null;

            tracking = false;
            TrackLocationButton.Content = "track location";
            StatusTextBlock.Text = "stopped";
        }
    }
    void geolocator_StatusChanged(Geolocator sender, StatusChangedEventArgs args)
    {
        string status = "";

        switch (args.Status)
        {
            case PositionStatus.Disabled:
                // the application does not have the right capability or the location master switch is off
                status = "location is disabled in phone settings";
                break;
            case PositionStatus.Initializing:
                // the geolocator started the tracking operation
                status = "initializing";
                break;
            case PositionStatus.NoData:
                // the location service was not able to acquire the location
                status = "no data";
                break;
            case PositionStatus.Ready:
                // the location service is generating geopositions as specified by the tracking parameters
                status = "ready";
                break;
            case PositionStatus.NotAvailable:
                status = "not available";
                // not used in WindowsPhone, Windows desktop uses this value to signal that there is no hardware capable to acquire location information
                break;
            case PositionStatus.NotInitialized:
                // the initial state of the geolocator, once the tracking operation is stopped by the user the geolocator moves back to this state

                break;
        }

        Dispatcher.BeginInvoke(() =>
        {
            StatusTextBlock.Text = status;
        });
    }





    void geolocator_PositionChanged(Geolocator sender, PositionChangedEventArgs args)
    {
        client.getPosCompleted += new EventHandler<ServiceReference2.getPosCompletedEventArgs>(sendData);

        client.getPosAsync(11,11);


        Dispatcher.BeginInvoke(() =>
        {
            LatitudeTextBlock.Text = args.Position.Coordinate.Latitude.ToString("0.00");
            LongitudeTextBlock.Text = args.Position.Coordinate.Longitude.ToString("0.00");
        });
    }


    public void sendData(object sender, ServiceReference2.getPosCompletedEventArgs e)
    {

        dd.Text = e.Result;

    }
    }

Answer 1

you have

client.getPosCompleted += new EventHandler<ServiceReference2.getPosCompletedEventArgs>(sendData);

but you haven't given Client any values anywhere else, I assume that you are getting a null Reference exception, and that this is why.

Answer 2

It just resolved it , just the fault of setting of IIS because mobile and pc are on different network so the communication is not possible .i just the forward the port in router setting –