nature_net.user_controls.custom_listbox_v2._list_PreviewTouchDown C# (CSharp) Метод

        private void _list_PreviewTouchDown(object sender, TouchEventArgs e)
        {
            if (e.Handled)
                return;
            if (!touch_points.ContainsKey(e.TouchDevice.Id))
            {
                touch_info t = new touch_info();
                t.id = e.TouchDevice.Id; t.is_tap = true; t.points.Add(e.GetTouchPoint(this._list as IInputElement));
                try { t.initial_attended_item = (Control)e.Source; }
                catch (Exception) { }
                this.touch_points.Add(e.TouchDevice.Id, t);
            }
            else
            {

            }
            FadingScrollViewer scroll = configurations.GetDescendantByType(this._list, typeof(FadingScrollViewer)) as FadingScrollViewer;
            if (is_horizontal)
                last_scroll_offset = scroll.HorizontalOffset;
            else
                last_scroll_offset = scroll.VerticalOffset;
            //scroll.Elasticity = new Vector(0.0, 0.4);

            if (configurations.right_panel_drag)
            {
                UIElement dragged_item = null;
                if (collection_list)
                    dragged_item = HitTestOverItem(e, true, false, false, true);
                else
                    dragged_item = HitTestOverItem(e, true, true, false, false);
                if (dragged_item != null)
                {
                    //avatar_drag(element, e.TouchDevice);
                    bool result = false;
                    if (dragged_item.GetType() == Type.GetType("nature_net.user_controls.item_generic_v2"))
                        result = start_drag((item_generic_v2)dragged_item, e);
                    if (dragged_item.GetType() == Type.GetType("nature_net.user_controls.collection_listbox_item"))
                        result = start_drag((collection_listbox_item)dragged_item, e.TouchDevice);

                    touch_points[e.TouchDevice.Id].is_drag = true;
                    touch_points[e.TouchDevice.Id].points.Clear();
                    touch_points[e.TouchDevice.Id].consecutive_drag_points = 0;
                    e.Handled = true;
                    touch_points.Remove(e.TouchDevice.Id);
                    return;
                }
            }

            if (configurations.manual_scroll)
            {
                bool r = e.TouchDevice.Capture(this._list as IInputElement, CaptureMode.SubTree);
                e.Handled = true;
                touch_points.Remove(e.TouchDevice.Id);
                return;
            }
            if (touch_points[e.TouchDevice.Id].initial_attended_item != null)
                attend_on_item(true, touch_points[e.TouchDevice.Id].initial_attended_item);
        }