GeoCoordinateWatcher isn't working after migration to WP8 - windows-phone-7

Question

I developed a navigation application for windows phone 7.1. It was running fine there. After updating to 8.0 my GeoCoordinateWatcher isnt working anymore. I know that I could use Geolocator instead, but I refuse to do so, because of lack of time.
For my app I read the current position of my watcher to store it for an object instance with location information. When I save my object instance the longitude and latitude are 0.0. Even when I change the position in my emulator still 0.0. The same issue occurs on my other pages, which use GeoCoordinateWatcher. It doesnt work. As I already said, on WP 7.1 - 7.8 it works very well.
public Map()
{
InitializeComponent();
watcher = new GeoCoordinateWatcher();
watcher.MovementThreshold = 20;
watcher.StatusChanged += new EventHandler<GeoPositionStatusChangedEventArgs>(watcher_StatusChanged);
watcher.PositionChanged += new EventHandler<GeoPositionChangedEventArgs<GeoCoordinate>>(watcher_PositionChanged);
}
void watcher_PositionChanged(object sender, GeoPositionChangedEventArgs<GeoCoordinate> e)
{
if (e.Position.Location.IsUnknown)
{
MessageBox.Show("Please wait while your prosition is determined.");
return;
}
geo.Latitude = e.Position.Location.Latitude;
geo.Longitude = e.Position.Location.Longitude;
}

Answer 1

try this code:
GeoCoordinateWatcher watch;
public GeoCoordinate loc = null;
public MainPage()
{
InitializeComponent();
if (watch == null)
{
watch = new GeoCoordinateWatcher(GeoPositionAccuracy.High)
{
MovementThreshold=10
};
watch.Start();
watch.PositionChanged += watch_PositionChanged;
}
}
void watch_PositionChanged(object sender, GeoPositionChangedEventArgs<GeoCoordinate> e)
{
//throw new NotImplementedException();
Dispatcher.BeginInvoke(()=>LocUpdate(e));
}
void LocUpdate(GeoPositionChangedEventArgs<GeoCoordinate> e)
{
try
{
location = new GeoCoordinate(e.Position.Location.Latitude, e.Position.Location.Longitude);
}
catch
{
MessageBox.Show("Error");
}
}