SilverlightMappingToolBasic.UI.SuperGraph.View.SuperGraphControl.UserControl_MouseWheel C# (CSharp) Method

        private void UserControl_MouseWheel(object sender, MouseWheelEventArgs e)
        {
            e.Handled = true;
            double x = 0, y = 0;
            if ((Keyboard.Modifiers & ModifierKeys.Control) == ModifierKeys.Control)
            {
                var previousLocation = _lastLocation;
                var old = Zoom;
                if (e.Delta > 0 && Zoom < 10)
                {
                    ZoomIn();
                }
                else if (e.Delta < 0 && Zoom > 0.1)
                {
                    ZoomOut();
                }

                if (!Zoom.Equals(old))
                {
                    y = _lastLocation.Y - previousLocation.Y;
                    x = _lastLocation.X - previousLocation.X;


                    if (ContextMenuContainer.ContextMenuVisibility == Visibility.Visible)
                    {
                        ContextMenuContainer.ContextMenuVisibility = Visibility.Collapsed;
                    }
                    MoveMap(x, y);
                }
            }
            else
            {
                if (e.Delta > 0)
                {
                    y = 30/Zoom;
                }
                else if (e.Delta < 0)
                {
                    y = -30/Zoom;
                }
                MoveMap(x, y);
            }
        }