protected override void UndoCore()
{
collection.Remove(index, count);
collection.SetRange(collection.Length - count, savedRange);
savedRange = null;
}
protected override void UndoCore()
{
collection.Remove(index, newRange.Length);
collection.SetRange(collection.Length - newRange.Length, savedRange);
savedRange = null;
}
protected override void UndoCore()
{
collection.SetRange(startIndex, oldRange);
oldRange = null;
}