protected override void SetComparerChain(IComparer <TSource> compareFunc)
        {
            OrderedReadOnlyContinuousCollection <TSource> previous = this.Source as OrderedReadOnlyContinuousCollection <TSource>;

            if (previous != null)
            {
                this.KeySorter = new ChainComparer(previous.KeySorter, compareFunc);
            }
        }
 public ThenByReadOnlyContinuousCollection(OrderedReadOnlyContinuousCollection <TSource> list,
                                           Expression <Func <TSource, TKey> > keySelectorExpression,
                                           bool descending)
     : base(list, keySelectorExpression, descending)
 {
 }