private static void DropTargetOnDragOver(object sender, DragEventArgs e, EventType eventType)
{
var elementPosition = e.GetPosition((IInputElement)sender);
var dragInfo = m_DragInfo;
var dropInfo = new DropInfo(sender, e, dragInfo, eventType);
var dropHandler = TryGetDropHandler(dropInfo, sender as UIElement);
var itemsControl = dropInfo.VisualTarget;
dropHandler.DragOver(dropInfo);
if (DragAdorner == null && dragInfo != null)
{
CreateDragAdorner(dropInfo);
}
DragAdorner?.Move(e.GetPosition(DragAdorner.AdornedElement), dragInfo != null ? GetDragMouseAnchorPoint(dragInfo.VisualSource) : default(Point), ref _adornerMousePosition, ref _adornerSize);
Scroll(dropInfo, e);
if (HitTestUtilities.HitTest4Type <ScrollBar>(sender, elementPosition) ||
HitTestUtilities.HitTest4GridViewColumnHeader(sender, elementPosition) ||
HitTestUtilities.HitTest4DataGridTypesOnDragOver(sender, elementPosition))
{
e.Effects = DragDropEffects.None;
e.Handled = true;
return;
}
// 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.
UIElement adornedElement = null;
if (itemsControl is TabControl)
{
adornedElement = itemsControl.GetVisualDescendent <TabPanel>();
}
else if (itemsControl is DataGrid || (itemsControl as ListView)?.View is GridView)
{
adornedElement = itemsControl.GetVisualDescendent <ScrollContentPresenter>() as UIElement ?? itemsControl.GetVisualDescendent <ItemsPresenter>() as UIElement ?? itemsControl;
}
else
{
adornedElement = itemsControl.GetVisualDescendent <ItemsPresenter>() as UIElement ?? 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, dropInfo);
}
var adorner = DropTargetAdorner;
if (adorner != null)
{
var adornerBrush = GetDropTargetAdornerBrush(dropInfo.VisualTarget);
if (adornerBrush != null)
{
adorner.Pen.Brush = adornerBrush;
}
adorner.DropInfo = dropInfo;
adorner.InvalidateVisual();
}
}
}
// Set the drag effect adorner if there is one
if (dragInfo != null && (EffectAdorner == null || EffectAdorner.Effects != dropInfo.Effects))
{
CreateEffectAdorner(dropInfo);
}
EffectAdorner?.Move(e.GetPosition(EffectAdorner.AdornedElement), default(Point), ref _effectAdornerMousePosition, ref _effectAdornerSize);
e.Effects = dropInfo.Effects;
e.Handled = !dropInfo.NotHandled;
if (!dropInfo.IsSameDragDropContextAsSource)
{
e.Effects = DragDropEffects.None;
}
}
private static void CreateDragAdorner(DropInfo dropInfo)
{
var dragInfo = dropInfo.DragInfo;
var template = GetDropAdornerTemplate(dropInfo.VisualTarget) ?? GetDragAdornerTemplate(dragInfo.VisualSource);
var templateSelector = GetDropAdornerTemplateSelector(dropInfo.VisualTarget) ?? GetDragAdornerTemplateSelector(dragInfo.VisualSource);
UIElement adornment = null;
var useDefaultDragAdorner = template == null && templateSelector == null && GetUseDefaultDragAdorner(dragInfo.VisualSource);
var useVisualSourceItemSizeForDragAdorner = GetUseVisualSourceItemSizeForDragAdorner(dragInfo.VisualSource);
if (useDefaultDragAdorner)
{
template = dragInfo.VisualSourceItem.GetCaptureScreenDataTemplate(dragInfo.VisualSourceFlowDirection);
}
if (template != null || templateSelector != null)
{
if (dragInfo.Data is IEnumerable && !(dragInfo.Data is string))
{
if (!useDefaultDragAdorner && ((IEnumerable)dragInfo.Data).Cast <object>().Count() <= 10)
{
var itemsControl = new ItemsControl();
itemsControl.ItemsSource = (IEnumerable)dragInfo.Data;
itemsControl.ItemTemplate = template;
itemsControl.ItemTemplateSelector = templateSelector;
itemsControl.Tag = dragInfo;
if (useVisualSourceItemSizeForDragAdorner)
{
var bounds = VisualTreeHelper.GetDescendantBounds(dragInfo.VisualSourceItem);
itemsControl.SetValue(FrameworkElement.MinWidthProperty, bounds.Width);
}
// The ItemsControl doesn't display unless we create a grid to contain it.
// Not quite sure why we need this...
var grid = new Grid();
grid.Children.Add(itemsControl);
adornment = grid;
}
}
else
{
var contentPresenter = new ContentPresenter();
contentPresenter.Content = dragInfo.Data;
contentPresenter.ContentTemplate = template;
contentPresenter.ContentTemplateSelector = templateSelector;
contentPresenter.Tag = dragInfo;
if (useVisualSourceItemSizeForDragAdorner)
{
var bounds = VisualTreeHelper.GetDescendantBounds(dragInfo.VisualSourceItem);
contentPresenter.SetValue(FrameworkElement.MinWidthProperty, bounds.Width);
contentPresenter.SetValue(FrameworkElement.MinHeightProperty, bounds.Height);
}
adornment = contentPresenter;
}
}
if (adornment != null)
{
if (useDefaultDragAdorner)
{
adornment.Opacity = GetDefaultDragAdornerOpacity(dragInfo.VisualSource);
}
var rootElement = RootElementFinder.FindRoot(dropInfo.VisualTarget ?? dragInfo.VisualSource);
DragAdorner = new DragAdorner(rootElement, adornment, GetDragAdornerTranslation(dragInfo.VisualSource));
}
}
