public Model.Picture Next()
        {
            if (Pictures.Count() == 0)
            {
                return(null);
            }

            ++_CurrentIndex;
            _CurrentIndex %= Pictures.Count();

            return(Pictures[_CurrentIndex]);
        }
        public Model.Picture Prev()
        {
            if (Pictures.Count() == 0)
            {
                return(null);
            }

            if (_CurrentIndex > 0)
            {
                --_CurrentIndex;
            }
            else
            {
                _CurrentIndex = Pictures.Count() - 1;
            }

            return(Pictures[_CurrentIndex]);
        }