private void DragOver(object sender, DragEventArgs e)
{
this.UpdateHelpers(sender, e);
DragPosition Position = new DragPosition(e);
this.uiHelper.ForEach(helper => helper.NotifyDrag(Position));
}
private void HandleDragUpdate(DragDropEffect effect, DragPosition position)
{
this.dragTargetHandler.NotifyDragChanged(effect, position);
}