private void Element_ManipulationDelta(object sender, ManipulationDeltaEventArgs e)
{
Debug.WriteLine("ManipulationDelta");
if (!IsActive)
{
return;
}
// set the event to handled in order to avoid scrolling the ScrollViewer
e.Handled = true;
// move our 'drag image'.
_dragImage.SetVerticalOffset(_dragImage.GetVerticalOffset().Value + e.DeltaManipulation.Translation.Y);
}
private void HoldDelta(object sender, ManipulationDeltaEventArgs e)
{
if (!IsEnabled)
{
return;
}
if (!IsActive && !ShouldActivate(e))
{
return;
}
e.Handled = true;
if (!IsActive)
{
IsActive = true;
var relativePosition = _cardView.GetRelativePositionIn(_itemsControl);
PopoutCard(_cardView, _dragImage, relativePosition);
_dispatcherTimer.Start();
}
var dragTop = _dragImage.GetVerticalOffset().Value;
var dragMid = _dragImage.ActualHeight / 2;
var potentialY = dragTop + e.DeltaManipulation.Translation.Y;
if (potentialY <= 0)
{
potentialY = 0;
}
var potentialIntersect = potentialY + dragMid + _scrollViewer.VerticalOffset;
if (potentialIntersect <= 0)
{
potentialIntersect = 0;
}
var isDownward = e.DeltaManipulation.Translation.Y > 0;
if (!isDownward && dragTop <= 0)
{
potentialIntersect = 0;
}
var potentialIndex = GetPotentialIndex(_currentIndex, potentialIntersect, isDownward);
if (_currentIndex != potentialIndex)
{
// We only want to reindex if the index we've moved the card to
// has changed, based on hardcore maths.
_pointIndex.ShuffleItems(_currentIndex, potentialIndex);
_currentIndex = potentialIndex;
}
// Move the drag image
_dragImage.SetVerticalOffset(potentialY);
}
private static void PopoutCard(UIElement element, DragImage image, Point relativePosition)
{
// Copy the selected card into a bitmap for use as the movement target
var bitmap = new WriteableBitmap(element, null);
image.Image.Source = bitmap;
image.Visibility = Visibility.Visible;
image.Opacity = 1.0;
// this needs to be relative to the scrolled position
image.SetVerticalOffset(relativePosition.Y);
//image.SetHorizontalOffset(relativePosition.X);
// hide the underlying item
element.Opacity = 0.0;
}