void ThumbDragStarted(object sender, DragStartedEventArgs e)
{
Thumb thumb = (Thumb)sender;
ScrollBar scrollBar = thumb.GetParent <ScrollBar>();
bool isVertical = scrollBar.Orientation == Orientation.Vertical;
// Update the content in the ToolTip
ScrollingPreviewData data = new ScrollingPreviewData();
data.UpdateScrollingValues(scrollBar);
data.UpdateItem(AssociatedObject as ItemsControl, isVertical);
_previewToolTip = new ToolTip
{
PlacementTarget = (UIElement)sender,
Placement = isVertical ? PlacementMode.Left : PlacementMode.Top,
VerticalOffset = 0.0,
HorizontalOffset = 0.0,
ContentTemplate = (isVertical)
? VerticalScrollingPreviewTemplate
: HorizontalScrollingPreviewTemplate,
Content = data,
IsOpen = true
};
}
void ThumbDragDelta(object sender, DragDeltaEventArgs e)
{
Thumb thumb = (Thumb)sender;
ScrollBar scrollBar = thumb.GetParent <ScrollBar>();
// Check that we're within the range of the ScrollBar
if ((_previewToolTip != null) &&
(scrollBar.Value > scrollBar.Minimum) &&
(scrollBar.Value < scrollBar.Maximum))
{
// This is a little trick to cause the ToolTip to update its position next to the Thumb
if (scrollBar.Orientation == Orientation.Vertical)
{
_previewToolTip.VerticalOffset = _previewToolTip.VerticalOffset == 0.0 ? 0.001 : 0.0;
}
else
{
_previewToolTip.HorizontalOffset = _previewToolTip.HorizontalOffset == 0.0 ? 0.001 : 0.0;
}
}
}