private bool _progressRingIsActive = true;
        public bool ProgressRingIsActive {
            get { return _progressRingIsActive; }
            set {
                if (_progressRingIsActive != value) {
                    _progressRingIsActive = value;
                    onPropertyChanged("ProgressRingIsActive");
                }
            }
        }

 <ProgressRing x:Name="pRing"
                      RelativePanel.Above="ForecastList"
                      RelativePanel.AlignHorizontalCenterWith="currentLocation"
                     IsActive="{Binding ProgressRingIsActive, UpdateSourceTrigger=PropertyChanged, Mode=TwoWay}"
                     RelativePanel.Below="currentLocation" />