public override NSDragOperation ValidateDrop(NSOutlineView outlineView, NSDraggingInfo info, NSObject item, nint index)
{
var h = Handler;
if (h == null)
{
return(NSDragOperation.None);
}
var etoInfo = GetDragInfo(info, item, index);
var e = h.GetDragEventArgs(info, etoInfo);
h.Callback.OnDragOver(h.Widget, e);
if (e.AllowedEffects.HasFlag(e.Effects))
{
if (etoInfo.Position == GridDragPosition.Over)
{
outlineView.SetDropItem(h.GetCachedItem(etoInfo.Item), -1);
}
else
{
outlineView.SetDropItem(h.GetCachedItem(etoInfo.Parent), etoInfo.InsertIndex);
}
return(e.Effects.ToNS());
}
else
{
return(NSDragOperation.None);
}
}