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);
}
}
}
}