private static void DropTarget_PreviewDragOver(object sender, DragEventArgs e)
{
var elementPosition = e.GetPosition((IInputElement)sender);
if (HitTestUtilities.HitTest4Type <ScrollBar>(sender, elementPosition) ||
HitTestUtilities.HitTest4GridViewColumnHeader(sender, elementPosition) ||
HitTestUtilities.HitTest4DataGridTypesOnDragOver(sender, elementPosition))
{
e.Effects = DragDropEffects.None;
e.Handled = true;
return;
}
var dropInfo = new DropInfo(sender, e, m_DragInfo);
var dropHandler = TryGetDropHandler(dropInfo, sender as UIElement);
var itemsControl = dropInfo.VisualTarget;
dropHandler.DragOver(dropInfo);
if (DragAdorner == null && m_DragInfo != null)
{
CreateDragAdorner();
}
if (DragAdorner != null)
{
var tempAdornerPos = e.GetPosition(DragAdorner.AdornedElement);
if (tempAdornerPos.X >= 0 && tempAdornerPos.Y >= 0)
{
_adornerPos = tempAdornerPos;
}
// Fixed the flickering adorner - Size changes to zero 'randomly'...?
if (DragAdorner.RenderSize.Width > 0 && DragAdorner.RenderSize.Height > 0)
{
_adornerSize = DragAdorner.RenderSize;
}
if (m_DragInfo != null)
{
// move the adorner
var offsetX = _adornerSize.Width * -GetDragMouseAnchorPoint(m_DragInfo.VisualSource).X;
var offsetY = _adornerSize.Height * -GetDragMouseAnchorPoint(m_DragInfo.VisualSource).Y;
_adornerPos.Offset(offsetX, offsetY);
var maxAdornerPosX = DragAdorner.AdornedElement.RenderSize.Width;
var adornerPosRightX = (_adornerPos.X + _adornerSize.Width);
if (adornerPosRightX > maxAdornerPosX)
{
_adornerPos.Offset(-adornerPosRightX + maxAdornerPosX, 0);
}
if (_adornerPos.Y < 0)
{
_adornerPos.Y = 0;
}
}
DragAdorner.MousePosition = _adornerPos;
DragAdorner.InvalidateVisual();
}
// If the target is an ItemsControl then update the drop target adorner.
if (itemsControl != null)
{
// Display the adorner in the control's ItemsPresenter. If there is no
// ItemsPresenter provided by the style, try getting hold of a
// ScrollContentPresenter and using that.
var adornedElement =
itemsControl is TabControl
? itemsControl.GetVisualDescendent <TabPanel>()
: (itemsControl.GetVisualDescendent <ItemsPresenter>() ?? itemsControl.GetVisualDescendent <ScrollContentPresenter>() as UIElement ?? itemsControl);
if (adornedElement != null)
{
if (dropInfo.DropTargetAdorner == null)
{
DropTargetAdorner = null;
}
else if (!dropInfo.DropTargetAdorner.IsInstanceOfType(DropTargetAdorner))
{
DropTargetAdorner = DropTargetAdorner.Create(dropInfo.DropTargetAdorner, adornedElement);
}
if (DropTargetAdorner != null)
{
DropTargetAdorner.DropInfo = dropInfo;
DropTargetAdorner.InvalidateVisual();
}
}
}
// Set the drag effect adorner if there is one
if (m_DragInfo != null && (EffectAdorner == null || EffectAdorner.Effects != dropInfo.Effects))
{
CreateEffectAdorner(dropInfo);
}
if (EffectAdorner != null)
{
var adornerPos = e.GetPosition(EffectAdorner.AdornedElement);
adornerPos.Offset(20, 20);
EffectAdorner.MousePosition = adornerPos;
EffectAdorner.InvalidateVisual();
}
e.Effects = dropInfo.Effects;
e.Handled = !dropInfo.NotHandled;
if (!dropInfo.IsSameDragDropContextAsSource)
{
e.Effects = DragDropEffects.None;
}
Scroll(dropInfo.VisualTarget, e);
}
private static void CreateDragAdorner()
{
var template = GetDragAdornerTemplate(m_DragInfo.VisualSource);
var templateSelector = GetDragAdornerTemplateSelector(m_DragInfo.VisualSource);
UIElement adornment = null;
var useDefaultDragAdorner = GetUseDefaultDragAdorner(m_DragInfo.VisualSource);
if (template == null && templateSelector == null && useDefaultDragAdorner)
{
var bs = CaptureScreen(m_DragInfo.VisualSourceItem, m_DragInfo.VisualSourceFlowDirection);
if (bs != null)
{
var factory = new FrameworkElementFactory(typeof(Image));
factory.SetValue(Image.SourceProperty, bs);
factory.SetValue(RenderOptions.EdgeModeProperty, EdgeMode.Aliased);
factory.SetValue(RenderOptions.BitmapScalingModeProperty, BitmapScalingMode.HighQuality);
factory.SetValue(FrameworkElement.WidthProperty, bs.Width);
factory.SetValue(FrameworkElement.HeightProperty, bs.Height);
factory.SetValue(FrameworkElement.HorizontalAlignmentProperty, HorizontalAlignment.Left);
factory.SetValue(FrameworkElement.VerticalAlignmentProperty, VerticalAlignment.Top);
template = new DataTemplate {
VisualTree = factory
};
}
}
if (template != null || templateSelector != null)
{
if (m_DragInfo.Data is IEnumerable && !(m_DragInfo.Data is string))
{
if (!useDefaultDragAdorner && ((IEnumerable)m_DragInfo.Data).Cast <object>().Count() <= 10)
{
var itemsControl = new ItemsControl();
itemsControl.ItemsSource = (IEnumerable)m_DragInfo.Data;
itemsControl.ItemTemplate = template;
itemsControl.ItemTemplateSelector = templateSelector;
// The ItemsControl doesn't display unless we create a border to contain it.
// Not quite sure why this is...
var border = new Border();
border.Child = itemsControl;
adornment = border;
}
}
else
{
var contentPresenter = new ContentPresenter();
contentPresenter.Content = m_DragInfo.Data;
contentPresenter.ContentTemplate = template;
contentPresenter.ContentTemplateSelector = templateSelector;
adornment = contentPresenter;
}
}
if (adornment != null)
{
if (useDefaultDragAdorner)
{
adornment.Opacity = GetDefaultDragAdornerOpacity(m_DragInfo.VisualSource);
}
var parentWindow = m_DragInfo.VisualSource.GetVisualAncestor <Window>();
var rootElement = parentWindow != null ? parentWindow.Content as UIElement : null;
if (rootElement == null && Application.Current != null && Application.Current.MainWindow != null)
{
rootElement = (UIElement)Application.Current.MainWindow.Content;
}
// i don't want the fu... windows forms reference
// if (rootElement == null) {
// var elementHost = m_DragInfo.VisualSource.GetVisualAncestor<ElementHost>();
// rootElement = elementHost != null ? elementHost.Child : null;
// }
if (rootElement == null)
{
rootElement = m_DragInfo.VisualSource.GetVisualAncestor <UserControl>();
}
DragAdorner = new DragAdorner(rootElement, adornment);
}
}
