private static void OnDragOver(object sender, [NotNull] DragEventArgs e)
{
// Unless we're over a control that accepts drop, we're going to reject the drop.
e.Effects = DragDropEffects.None;
dataType = DisplayDropAdorner.Never;
var items = DragDropHelper.GetItemsToDrop(DragDropHelper.GetDragContainer(e.Data), e.Data as DataObject);
if (items != null)
{
var isInternal = DragDropHelper.ShouldDisplayDropAdorner(DisplayDropAdorner.InternalOnly, items);
var isExternal = DragDropHelper.ShouldDisplayDropAdorner(DisplayDropAdorner.ExternalOnly, items);
dataType = (isInternal ? DisplayDropAdorner.InternalOnly : DisplayDropAdorner.Never)
| (isExternal ? DisplayDropAdorner.ExternalOnly : DisplayDropAdorner.Never);
}
Activate();
DragLeaveTimer.Reset();
}
internal static bool ShouldDisplayDropAdorner(DisplayDropAdorner rule, IEnumerable <object> itemsToDrop)
{
switch (rule)
{
case DisplayDropAdorner.Never:
return(false);
case DisplayDropAdorner.InternalOnly:
return(itemsToDrop.All(x => !(x is UFile)));
case DisplayDropAdorner.ExternalOnly:
return(itemsToDrop.All(x => x is UFile));
case DisplayDropAdorner.Always:
return(true);
default:
throw new ArgumentOutOfRangeException(nameof(rule));
}
}
