private void Drop(object sender, DragEventArgs e)
{
if (TreeArrange.AdornmentTarget(sender) is not {
} droppedOnElement)
{
return;
}
if (ExtractDraggedData(e) is not {
} draggedItem)
{
TrySendSupplementalDropMessage(sender, e);
return;
}
if (TreeArrange.FindDraggedItem(droppedOnElement) is not {
} target || target == draggedItem)
{
return;
}
if (DroppingItemOnOwnChild(droppedOnElement, draggedItem))
{
return;
}
if (ListFinder.FindParentListContainingData(droppedOnElement, target) is not {
} items)
{
return;
}
e.Handled = true;
e.Effects = ComputeAdornerType(RelativePosition(e, droppedOnElement), HasChildList(droppedOnElement, draggedItem)) switch
{
DropAdornerKind.Top => InsertDroppedItemIntoTarget(items, target, draggedItem, 0),
DropAdornerKind.Bottom => InsertDroppedItemIntoTarget(items, target, draggedItem, 1),
_ => InsertDroppedItemIntoTarget(
ListFinder.FindChildListToHoldData(droppedOnElement, draggedItem) ?? items, null, draggedItem, 0)
};
}
private static bool HasChildList(FrameworkElement droppedOnElement, object droppedData) => ListFinder.FindChildListToHoldData(droppedOnElement, droppedData) is not null;