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, _dragInfo);
var dropHandler = GetDropHandler((UIElement)sender);
if (dropHandler == null)
{
// sender does not have DropHandler attached property set.
// use default drop target in that case
dropHandler = DefaultDropTarget;
}
var itemsControl = dropInfo.VisualTarget;
dropHandler.DragOver(dropInfo);
if (DragAdorner == null && _dragInfo != null)
{
CreateDragAdorner();
}
if (DragAdorner != null)
{
var tempAdornerPos = e.GetPosition(DragAdorner.AdornedElement);
if (tempAdornerPos.X > 0 && tempAdornerPos.Y > 0)
{
_adornerPos = tempAdornerPos;
}
if (DragAdorner.RenderSize.Width > 0 && DragAdorner.RenderSize.Height > 0)
{
_adornerSize = DragAdorner.RenderSize;
}
if (_dragInfo != null)
{
// move the adorner
var offsetX = _adornerSize.Width * -GetDragMouseAnchorPoint(_dragInfo.VisualSource).X;
var offsetY = _adornerSize.Height * -GetDragMouseAnchorPoint(_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);
}
}
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 =
(UIElement)itemsControl.FindVisualDescendant<ItemsPresenter>() ??
(UIElement)itemsControl.FindVisualDescendant<ScrollContentPresenter>();
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 (EffectAdorner == null && _dragInfo != null)
{
CreateEffectAdorner(dropInfo);
}
if (EffectAdorner != null)
{
var adornerPos = e.GetPosition(EffectAdorner.AdornedElement);
adornerPos.Offset(20, 20);
EffectAdorner.MousePosition = adornerPos;
EffectAdorner.InvalidateVisual();
}
e.Effects = dropInfo.AllowedEffects;
e.Handled = true;
if(e.Effects != DragDropEffects.None)
Scroll((DependencyObject)dropInfo.VisualTarget, e);
}
private static void DropTarget_PreviewDrop(object sender, DragEventArgs e)
{
var local_dragInfo = _dragInfo;
if (local_dragInfo == null)
{
//NOTE: internal drag info may be null if drag operation did not originate from control using this DragDrop implementation
// (e.g. outside of wpf app)
// In that case convert DragEventArgs to DragInfo representation and then use it
local_dragInfo = DragInfo.CreateFromEvent(sender, e);
}
var dropInfo = new DropInfo(sender, e, local_dragInfo);
var dropHandler = GetDropHandler((UIElement)sender) ?? DefaultDropTarget;
var dragHandler = GetDragSource(local_dragInfo, sender as UIElement);
DragAdorner = null;
EffectAdorner = null;
DropTargetAdorner = null;
dropHandler.Drop(dropInfo);
dragHandler.Dropped(dropInfo);
Mouse.OverrideCursor = null;
e.Handled = true;
}
private static void CreateEffectAdorner(DropInfo dropInfo)
{
var template = GetEffectAdornerTemplate(dropInfo.VisualTarget, dropInfo.AllowedEffects, dropInfo.DestinationText);
if (template != null)
{
var rootElement = (UIElement)Application.Current.MainWindow.Content;
UIElement adornment = null;
var contentPresenter = new ContentPresenter();
contentPresenter.Content = _dragInfo.Data;
contentPresenter.ContentTemplate = template;
adornment = contentPresenter;
EffectAdorner = new DragAdorner(rootElement, adornment);
}
}