/// <summary>
/// Invoked when this page is about to be displayed in a Frame.
/// </summary>
/// <param name="e">Event data that describes how this page was reached. The Parameter
/// property is typically used to configure the page.</param>
protected override void OnNavigatedTo(NavigationEventArgs e)
{
// See if our background task is already registered.
_geolocTask = MainPage.LookupBackgroundTask(BackgroundTaskName);
if (_geolocTask != null)
{
// Associate an event handler with the existing background task
_geolocTask.Completed += OnCompleted;
}
UpdateButtonStates();
}