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Await of MapLocationFinder.FindLocationsAtAsync never ends

With the await of MapLocationFinder my program still runs, even after trying to close it with Application.Current.Shutdown();. I'm a beginer.
I already tried to use CancellationToken or run this as Task. But I don't know if I had done this in the right way. I tried different thinks for some hours but nothing worked for me.
private async Task GetLocation()
{
var accesStatus = await Geolocator.RequestAccessAsync();
switch (accesStatus)
{
case GeolocationAccessStatus.Allowed:
// locate user
var locator = new Windows.Devices.Geolocation.Geolocator();
var location = await locator.GetGeopositionAsync();
var position = location.Coordinate.Point.Position;
// get city name
Geopoint geopoint = new Geopoint(new BasicGeoposition
{
Latitude = position.Latitude,
Longitude = position.Longitude
});
Here the problem starts
MapLocationFinderResult result = await MapLocationFinder.FindLocationsAtAsync(geopoint, MapLocationDesiredAccuracy.Low);
if (result.Status == MapLocationFinderStatus.Success)
{
locationBlock.Text = "City: " + result.Locations[0].Address.Town;
}
problem ended, the rest is just for the context
// calculate time
int[] sun = SunDate.CalculateSunriseSunset(51.434406, 6.762329);
var sunrise = new DateTime(1, 1, 1, sun[0] / 60, sun[0] - (sun[0] / 60) * 60, 0);
var sunset = new DateTime(1, 1, 1, sun[1] / 60, sun[1] - (sun[1] / 60) * 60, 0);
//fit UI
lightStartBox.Text = sunrise.Hour.ToString();
darkStartBox.Text = sunset.Hour.ToString();
// apply settings
lightStartBox.IsEnabled = false;
darkStartBox.IsEnabled = false;
break;
case GeolocationAccessStatus.Denied:
locationCheckBox.IsChecked = false;
locationBlock.Text = "The App needs permission to location";
await Windows.System.Launcher.LaunchUriAsync(new Uri("ms-settings:privacy-location"));
break;
case GeolocationAccessStatus.Unspecified:
locationCheckBox.IsChecked = false;
locationBlock.Text = "The App needs permission to location";
await Windows.System.Launcher.LaunchUriAsync(new Uri("ms-settings:privacy-location"));
break;
}
return;
}
If I close the program, it should also end the await task. Better: It should end the operation after he got the info.

If I close the program, it should also end the await task. Better: It should end the operation after he got the info.
I have run your code, but I could not reproduce the issue, I could get MapLocationFinderResult with low delay. I found you used MapLocationDesiredAccuracy.Low parameter. And it will leverage the maps disk cache to get accurate info up to the city level. maps disk cache may cause this issue. You could try to use MapLocationDesiredAccuracy.High parameter.
As you see, FindLocationsAtAsync is IAsyncOperation method. So, you could cancel it manually or set timeout cancel token.
For example
private IAsyncOperation<string> GetAsyncOperation()
{
return AsyncInfo.Run<string>(
(token) => // CancellationToken token
Task.Run<string>(
() =>
{
token.WaitHandle.WaitOne(3000);
token.ThrowIfCancellationRequested();
return "hello";
},
token));
}
private IAsyncOperation<string> operation;
private async void Button_Click(object sender, RoutedEventArgs e)
{
try
{
operation = GetAsyncOperation();
var res = await operation;
}
catch (Exception)
{
System.Diagnostics.Debug.WriteLine("method end");
}
}
private void Cancel_Button_Click(object sender, RoutedEventArgs e)
{
operation?.Cancel();
}
Set Timeout
private async void Button_Click(object sender, RoutedEventArgs e)
{
var source = new CancellationTokenSource(4000);
var res = await GetAsyncOperation().AsTask(source.Token);
}

Looks like this is a known bug
To work-around it I ended up setting a static flag on my App class so that when the app was shutting down it would force kill the process.
// Before call to MapLocationFinder.FindLocationsAsync()
App.RequiresProcessKill = true;
and then in my shutdown process (ie in the OnClosed method of your main window) I forced closed the app if neccessary:
protected override void OnClosed(EventArgs e)
{
base.OnClosed(e);
if (App.RequiresProcessKill)
{
var self = Process.GetCurrentProcess();
self.Kill();
}
}

GetGeopositionAsync takes too long to complete

current I use this code to get GPS:
Geolocator geolocator = new Geolocator();
geolocator.DesiredAccuracy = PositionAccuracy.Default;
geolocator.DesiredAccuracyInMeters = 50;
try
{
Geoposition currentPosition = await geolocator.GetGeopositionAsync(TimeSpan.FromSeconds(120), TimeSpan.FromSeconds(30));
MyCoordinate = new GeoCoordinate(currentPosition.Coordinate.Latitude, currentPosition.Coordinate.Longitude);
}
catch (Exception ex)
{
if (ex.Message.Contains("This operation returned because the timeout period expired."))
{
MessageBox.Show("GPS is taking too long too complete. Pleaes try again.");
this.SetProgressIndicator(false);
RadBusyIndicator.IsRunning = false;
return;
}
else
{
this.SetProgressIndicator(false);
RadBusyIndicator.IsRunning = false;
return;
}
};
But it always takes too long to complete, as you can see I set timeout 30s but not sure why
it doesn't show timeout exception when took more than 30s.
I'm getting stuck on this issue. Does anyone have any idea?

Make sure the wifi or cellphone device is on, this enables the fallback methods to be used when the GPS device can't find a signal.
Someone with more or less the same problem made another thread in here:
GetGeopositionAsync does not return
More information on the GeoLocator class:
http://msdn.microsoft.com/en-us/library/windows/apps/windows.devices.geolocation.geolocator#properties

I don't know why too, but TimeSpanis realy slow, but doing it with ReportInterval works fine:
geolocator = new Geolocator();
geolocator.DesiredAccuracy = PositionAccuracy.High;
geolocator.ReportInterval = 2000;
geolocator.PositionChanged += geolocator_PositionChanged;
private void geolocator_PositionChanged(Geolocator sender, PositionChangedEventArgs args)
{
try
{
Dispatcher.BeginInvoke(() =>
{
myPosition = args.Position.Coordinate.ToGeoCoordinate();
});
}
catch(Exception ex)
{
if (ex.Data == null) throw;
else MessageBox.Show("Exception while Tracking: " + ex.InnerException.ToString());
}
}

Error in get location windows phone 8

I developing windows phone 8 application
I need to get the user current location city and state name on page load (Application start)
I tryed with following code
public SplashPage()
{
InitializeComponent();
GetCurrentCoordinate();
}
private async void GetCurrentCoordinate()
{
Geolocator geolocator = new Geolocator();
geolocator.DesiredAccuracy = PositionAccuracy.High;
try
{
Geoposition currentPosition = await geolocator.GetGeopositionAsync(TimeSpan.FromMinutes(1), TimeSpan.FromSeconds(10));
_accuracy = currentPosition.Coordinate.Accuracy;
MyCoordinate = new GeoCoordinate(currentPosition.Coordinate.Latitude, currentPosition.Coordinate.Longitude);
if (MyReverseGeocodeQuery == null || !MyReverseGeocodeQuery.IsBusy)
{
MyReverseGeocodeQuery = new ReverseGeocodeQuery();
MyReverseGeocodeQuery.GeoCoordinate = new GeoCoordinate(MyCoordinate.Latitude, MyCoordinate.Longitude);
MyReverseGeocodeQuery.QueryCompleted += MyReverseGeocodeQuery_QueryCompleted;
MyReverseGeocodeQuery.QueryAsync();
}
}
catch (Exception ex)
{
}
}
private void MyReverseGeocodeQuery_QueryCompleted(object sender, QueryCompletedEventArgs<IList<Microsoft.Phone.Maps.Services.MapLocation>> e)
{
if (e.Error == null)
{
if (e.Result.Count > 0)
{
MapAddress address = e.Result[0].Information.Address;
CurrentLocTextBlock.Text = "Current Location: " + address.City + ", " + address.State;
}
}
}
if i run the above code it's come to try block and not move to next line
MyCoordinate = new GeoCoordinate(currentPosition.Coordinate.Latitude, currentPosition.Coordinate.Longitude);"
some times code move to next line and result come. but most of time it's not go to next line.
how to overcome this. why this problem occur?

you need to add a timeout procedure by your self.
Geolocator geolocator = new Geolocator();
// get the async task
var asyncResult = geolocator.GetGeopositionAsync();
var task = asyncResult.AsTask();
// add a race condition - task vs timeout task
var readyTask = await Task.WhenAny(task, Task.Delay(10000));
if (readyTask != task) // timeout wins
throw new TimeoutException();
// position found within timeout
var pos = await task;
return pos;
Refered from GEOLOCATOR.GETGEOPOSITIONASYNC WITH CORRECT TIMEOUT

You missed a word "GeoCoordinate" at the beginning of current line
GeoCoordinate MyCoordinate = new GeoCoordinate

After you get your current position (GeoCoordinate), do this:
private void findAddress(GeoCoordinate myCoordinate)
{
if (reverseGeocode != null) reverseGeocode = null;
reverseGeocode = new ReverseGeocodeQuery();
reverseGeocode.GeoCoordinate = myCoordinate;
reverseGeocode.QueryCompleted += reverseGeocode_QueryCompleted;
reverseGeocode.QueryAsync();
}
void reverseGeocode_QueryCompleted(object sender, QueryCompletedEventArgs<IList<MapLocation>> e)
{
if (e.Error == null && e.Result.Count > 0)
{
//Here you got all information about your current coordinate/position
MapAddress myPositionAddress = null;
myPositionAddress = e.Result.FirstOrDefault().Information.Address;
}
}

Waiting on the results of GetGeopositionAsync()

I'm developing a WinPhone 8 App.
On this App there is a Button 'Send SMS'.
When the user clicks on this button two things should happen:
(Method A) Get the geo-coordinate of the current Location (using Geolocator and GetGeopositionAsync).
(Method B) Compose and send an SMS with the geo-coordinate as part of the body.
The Problem: GetGeopositionAsync is an asynchronous method. Before the coordinate is detected (which takes a few seconds) the SMS is sent (of course with no coordinates).
How can I tell Method 2 to wait until the coordinates are available?
OK, here is my code:
When the user presses the button, the coordinates are determined by the first method and the second method sends the SMS which includes the coordinates in its body:
private void btnSendSms_Click(object sender, RoutedEventArgs e)
{
GetCurrentCoordinate(); // Method 1
// -> Gets the coordinates
SendSms(); // Method 2
// Sends the coordinates within the body text
}
The first method GetCurrentCoordinate() looks as follows:
...
private GeoCoordinate MyCoordinate = null;
private ReverseGeocodeQuery MyReverseGeocodeQuery = null;
private double _accuracy = 0.0;
...
private async void GetCurrentCoordinate()
{
Geolocator geolocator = new Geolocator();
geolocator.DesiredAccuracy = PositionAccuracy.High;
try
{
Geoposition currentPosition = await geolocator.GetGeopositionAsync(
TimeSpan.FromMinutes(1),
TimeSpan.FromSeconds(10));
lblLatitude.Text = currentPosition.Coordinate.Latitude.ToString("0.000");
lblLongitude.Text = currentPosition.Coordinate.Longitude.ToString("0.000");
_accuracy = currentPosition.Coordinate.Accuracy;
MyCoordinate = new GeoCoordinate(
currentPosition.Coordinate.Latitude,
currentPosition.Coordinate.Longitude);
if (MyReverseGeocodeQuery == null || !MyReverseGeocodeQuery.IsBusy)
{
MyReverseGeocodeQuery = new ReverseGeocodeQuery();
MyReverseGeocodeQuery.GeoCoordinate = new GeoCoordinate(
MyCoordinate.Latitude,
MyCoordinate.Longitude);
MyReverseGeocodeQuery.QueryCompleted += ReverseGeocodeQuery_QueryCompleted;
MyReverseGeocodeQuery.QueryAsync();
}
}
catch (Exception)
{ // Do something }
}
private void ReverseGeocodeQuery_QueryCompleted(object sender,
QueryCompletedEventArgs<IList<MapLocation>> e)
{
if (e.Error == null)
{
if (e.Result.Count > 0)
{
MapAddress address = e.Result[0].Information.Address;
lblCurrAddress.Text = address.Street + " " + address.HouseNumber + ",\r" +
address.PostalCode + " " + address.City + ",\r" +
address.Country + " (" + address.CountryCode + ")";
}
}
}
}
And the Methode 'SendSms()':
private void SendSms()
{
SmsComposeTask smsComposeTask = new SmsComposeTask();
smsComposeTask.To = "0123456";
smsComposeTask.Body = "Current position: \rLat = " + lblLatitude.Text +
", Long = " + lblLongitude.Text +
"\r" + lblCurrAddress.Text;
// -> The TextBoxes are still empty!
smsComposeTask.Show();
}
The problem is, that all these TextBoxes (lblLatitude, lblLongitude, lblCurrAddress) are still empty when the method SendSms() sets the SmsComposeTask object.
I have to ensure that the TextBoxes are already set BEFORE the method SendSms() starts.

You should almost never mark a method async void unless it's a UI event handler. You're calling an asynchronous method without waiting for it to end. You are basically calling those 2 methods in parallel, so it's clear why the coordinates aren't available.
You need to make GetCurrentCoordinate return an awaitable task and await it, like this:
private async Task GetCurrentCoordinateAsync()
{
//....
}
private async void btnSendSms_Click(object sender, RoutedEventArgs e)
{
await GetCurrentCoordinateAsync();
// You'll get here only after the first method finished asynchronously.
SendSms();
}

This is one of the primary reasons you should avoid async void. void is a very unnatural return type for async methods.
First, make your GetCurrentCoordinate an async Task method instead of async void. Then, you can change your click handler to look like this:
private async void btnSendSms_Click(object sender, RoutedEventArgs e)
{
await GetCurrentCoordinate();
SendSms();
}
Your click handler is async void only because event handlers have to return void. But you should really strive to avoid async void in all other code.

There two things you're doing wrong here:
Using void returning async methods when you need to await on them. This is bad because you can't await on execution of these methods and should only be used when you can't make the method return Task or Task<T>. That's why you're not seeing anything on the text boxes when SendSmsis called.
Mixing UI and non-UI code. You should transfer data between UI and non-UI code to avoid tight coupling between code with different responsibilities. IT also makes it easy to read and debug the code.
ReverseGeocodeQuery does not have an awaitable async API but you can easily make your own:
private async Task<IList<MapLocation>> ReverseGeocodeQueryAsync(GeoCoordinate geoCoordinate)
{
var tcs = new TaskCompletionSource<IList<MapLocation>>();
EventHandler<QueryCompletedEventArgs<IList<MapLocation>>> handler =
(s, e) =>
{
if (e.Cacelled)
{
tcs.TrySetCancelled();
}
else if (e.Error != null)
{
tcs.TrySetException(e.Error);
}
else
{
tcs.TrySetResult(e.Result);
}
};
var query = new ReverseGeocodeQuery{ GeoCoordinate = geoCoordinate };
try
{
query.QueryCompleted += handler;
query.QueryAsync();
return await tcs.Task;
}
finally
{
query.QueryCompleted -= handler;
}
}
This way you'll get full cancellation and error support.
Now let's make the retrieval of the geo coordinate information all in one chunk:
private async Task<Tuple<Geocoordinate, MapLocation>> GetCurrentCoordinateAsync()
{
try
{
var geolocator = new Geolocator
{
DesiredAccuracy = PositionAccuracy.High
};
var currentPosition = await geolocator.GetGeopositionAsync(
TimeSpan.FromMinutes(1),
TimeSpan.FromSeconds(10))
.ConfigureAwait(continueOnCapturedContext: false);
var currentCoordinate = currentPosition.Coordinate;
var mapLocation = await this.ReverseGeocodeQueryAsync(
new GeoCoordinate(
currentCoordinate.Latitude,
currentCoordinate.Longitude));
return Tuple.Create(
currentCoordinate,
mapLocation.FirstOrDefault());
}
catch (Exception)
{
// Do something...
return Tuple.Create(null, null);
}
}
Now the button eventnt handler becomes much more readable:
private void btnSendSms_Click(object sender, RoutedEventArgs e)
{
var info = await GetCurrentCoordinate();
if (info.Item1 != nuil)
{
lblLatitude.Text = info.Item1.Latitude.ToString("0.000");
lblLongitude.Text = info.Item1.Longitude.ToString("0.000");
}
if (info.Item2 != null)
{
var address = info.Item2.Information.Address;
lblCurrAddress.Text = string.Format(
"{0} {1},\n{2} {3},\n{4} ({5})",
address.Street,
address.HouseNumber,
address.PostalCode,
address.City,
address.Country,
address.CountryCode);
}
SendSms(info.Item1, info.Item2);
}
Does this make sense?

Exception while tracking location in Windows Phone 8

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;
}
}

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.

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 –