SuperMap.WinRT.Actions.DrawPolygon.OnTapped C# (CSharp) Method

        public override void OnTapped(TappedRoutedEventArgs e)
        {
            base.OnTapped(e);

            Point2D item = Map.ScreenToMap(e.GetPosition(Map));

            if (!_isActivated)
            {
                this.Activate(item);
            }
            else
            {
                while (_points.Count > _pointsCount)
                {
                    _points.RemoveAt(_points.Count - 2);
                }
                _points.Insert(_points.Count - 1, item);
                _pointsCount++;
            }
        }