Esempio n. 1
0
        private void RectangleSelection_PointerMoved(object sender, PointerRoutedEventArgs e)
        {
            if (scrollViewer == null)
            {
                return;
            }

            var currentPoint   = e.GetCurrentPoint(uiElement);
            var verticalOffset = scrollViewer.VerticalOffset;

            if (selectionState == SelectionState.Starting)
            {
                if (!HasMovedMinimalDelta(originDragPoint.X, originDragPoint.Y - verticalOffset, currentPoint.Position.X, currentPoint.Position.Y))
                {
                    return;
                }

                // Clear selected items once if the pointer is pressed and moved
                selectionStrategy.StartSelection();
                OnSelectionStarted();
                selectionState = SelectionState.Active;
            }
            if (currentPoint.Properties.IsLeftButtonPressed)
            {
                var originDragPointShifted = new Point(originDragPoint.X, originDragPoint.Y - verticalOffset); // Initial drag point relative to the topleft corner
                base.DrawRectangle(currentPoint, originDragPointShifted, uiElement);
                // Selected area considering scrolled offset
                var rect = new System.Drawing.Rectangle((int)Canvas.GetLeft(selectionRectangle), (int)Math.Min(originDragPoint.Y, currentPoint.Position.Y + verticalOffset), (int)selectionRectangle.Width, (int)Math.Abs(originDragPoint.Y - (currentPoint.Position.Y + verticalOffset)));
                foreach (var item in uiElement.Items.ToList().Except(itemsPosition.Keys))
                {
                    var listViewItem = (FrameworkElement)uiElement.ContainerFromItem(item); // Get ListViewItem
                    if (listViewItem == null)
                    {
                        continue; // Element is not loaded (virtualized list)
                    }

                    var gt             = listViewItem.TransformToVisual(uiElement);
                    var itemStartPoint = gt.TransformPoint(new Point(0, verticalOffset)); // Get item position relative to the top of the list (considering scrolled offset)
                    var itemRect       = new System.Drawing.Rectangle((int)itemStartPoint.X, (int)itemStartPoint.Y, (int)listViewItem.ActualWidth, (int)listViewItem.ActualHeight);
                    itemsPosition[item] = itemRect;
                }

                foreach (var item in itemsPosition.ToList())
                {
                    try
                    {
                        if (rect.IntersectsWith(item.Value))
                        {
                            selectionStrategy.HandleIntersectionWithItem(item.Key);
                        }
                        else
                        {
                            selectionStrategy.HandleNoIntersectionWithItem(item.Key);
                        }
                    }
                    catch (ArgumentException)
                    {
                        // Item is not present in the ItemsSource
                        itemsPosition.Remove(item);
                    }
                }
                if (currentPoint.Position.Y > uiElement.ActualHeight - 20)
                {
                    // Scroll down the list if pointer is at the bottom
                    var scrollIncrement = Math.Min(currentPoint.Position.Y - (uiElement.ActualHeight - 20), 40);
                    scrollViewer.ChangeView(null, verticalOffset + scrollIncrement, null, false);
                }
                else if (currentPoint.Position.Y < 20)
                {
                    // Scroll up the list if pointer is at the top
                    var scrollIncrement = Math.Min(20 - currentPoint.Position.Y, 40);
                    scrollViewer.ChangeView(null, verticalOffset - scrollIncrement, null, false);
                }
            }
        }
        private void RectangleSelection_PointerMoved(object sender, PointerRoutedEventArgs e)
        {
            if (scrollBar == null)
            {
                return;
            }

            var currentPoint   = e.GetCurrentPoint(uiElement);
            var verticalOffset = scrollBar.Value - uiElement.ColumnHeaderHeight;

            if (selectionState == SelectionState.Starting)
            {
                if (!HasMovedMinimalDelta(originDragPoint.X, originDragPoint.Y - verticalOffset, currentPoint.Position.X, currentPoint.Position.Y))
                {
                    return;
                }

                if (uiElement.CurrentColumn != null)
                {
                    uiElement.CancelEdit();
                }
                selectionStrategy.StartSelection();
                OnSelectionStarted();
                selectionState = SelectionState.Active;
            }

            if (currentPoint.Properties.IsLeftButtonPressed)
            {
                var originDragPointShifted = new Point(originDragPoint.X, originDragPoint.Y - verticalOffset); // Initial drag point relative to the topleft corner
                base.DrawRectangle(currentPoint, originDragPointShifted, uiElement);
                // Selected area considering scrolled offset
                var    rect = new System.Drawing.Rectangle((int)Canvas.GetLeft(selectionRectangle), (int)Math.Min(originDragPoint.Y, currentPoint.Position.Y + verticalOffset), (int)selectionRectangle.Width, (int)Math.Abs(originDragPoint.Y - (currentPoint.Position.Y + verticalOffset)));
                var    dataGridRowsPosition = new Dictionary <DataGridRow, System.Drawing.Rectangle>();
                double actualWidth          = -1;
                foreach (var row in dataGridRows)
                {
                    if (row.Visibility != Visibility.Visible)
                    {
                        continue; // Skip invalid/invisible rows
                    }

                    if (actualWidth < 0)
                    {
                        var temp = new List <DataGridCell>();
                        DependencyObjectHelpers.FindChildren <DataGridCell>(temp, row); // Find cells inside row
                        actualWidth = temp.Sum(x => x.ActualWidth);                     // row.ActualWidth reports incorrect width
                    }

                    var gt             = row.TransformToVisual(uiElement);
                    var itemStartPoint = gt.TransformPoint(new Point(0, verticalOffset)); // Get item position relative to the top of the list (considering scrolled offset)
                    var itemRect       = new System.Drawing.Rectangle((int)itemStartPoint.X, (int)itemStartPoint.Y, (int)actualWidth, (int)row.ActualHeight);
                    itemsPosition[row.DataContext] = itemRect;                            // Update item position
                    dataGridRowsPosition[row]      = itemRect;                            // Update ui row position
                }

                foreach (var item in itemsPosition.ToList())
                {
                    try
                    {
                        if (rect.IntersectsWith(item.Value))
                        {
                            selectionStrategy.HandleIntersectionWithItem(item.Key);
                        }
                        else
                        {
                            selectionStrategy.HandleNoIntersectionWithItem(item.Key);
                        }
                    }
                    catch (ArgumentException)
                    {
                        // Item is not present in the ItemsSource
                        itemsPosition.Remove(item);
                    }
                }
                if (currentPoint.Position.Y > uiElement.ActualHeight - 20)
                {
                    // Scroll down the list if pointer is at the bottom
                    // Check if there is a loaded row outside the viewport
                    var item = dataGridRowsPosition.OrderBy(x => x.Value.Y).SkipWhile(x => x.Value.Y <= verticalOffset + uiElement.ActualHeight).Select(x => x.Key).FirstOrDefault();
                    if (item == null)
                    {
                        if (dataGridRowsPosition.Any())
                        {
                            // Last loaded item is fully visible, ge thet next one from bound item source
                            var index  = dataGridRowsPosition.OrderBy(x => x.Value.Y).Last().Key.GetIndex();
                            var source = (System.Collections.IList)uiElement.ItemsSource;
                            uiElement.ScrollIntoView(source[Math.Min(Math.Max(index + 1, 0), source.Count - 1)], null);
                        }
                    }
                    else
                    {
                        uiElement.ScrollIntoView(item.DataContext, null);
                    }
                }
                else if (currentPoint.Position.Y < 20)
                {
                    // Scroll up the list if pointer is at the top
                    // Check if there is a loaded row outside the viewport
                    var item = dataGridRowsPosition.OrderBy(x => x.Value.Y).TakeWhile(x => x.Value.Y + x.Value.Height <= scrollBar.Value).Select(x => x.Key).LastOrDefault();
                    if (item == null)
                    {
                        if (dataGridRowsPosition.Any())
                        {
                            // First loaded item is fully visible, ge thet previous one from bound item source
                            var index  = dataGridRowsPosition.OrderBy(x => x.Value.Y).First().Key.GetIndex();
                            var source = (System.Collections.IList)uiElement.ItemsSource;
                            uiElement.ScrollIntoView(source[Math.Min(Math.Max(index - 1, 0), source.Count - 1)], null);
                        }
                    }
                    else
                    {
                        uiElement.ScrollIntoView(item.DataContext, null);
                    }
                }
            }
        }