public AdvancedSearchViewModel()
        {
            AdvancedSearchFilter lastFilter = null;
            AdvancedSearchFilter filter = null; 

            for (var i = 0; i < 10; i++)
            {
                filter = new AdvancedSearchFilter { Number = i, IsEnabled = true };

                if (lastFilter != null)
                {
                    lastFilter.Next = filter;
                }

                _filters.Add(filter);

                lastFilter = filter;
            }
        }
        public AdvancedSearchViewModel()
        {
            AdvancedSearchFilter lastFilter = null;
            AdvancedSearchFilter filter     = null;

            for (var i = 0; i < 10; i++)
            {
                filter = new AdvancedSearchFilter {
                    Number = i, IsEnabled = true
                };

                if (lastFilter != null)
                {
                    lastFilter.Next = filter;
                }

                _filters.Add(filter);

                lastFilter = filter;
            }
        }