public static IEnumerable<TreeViewItemViewModel> CreateViewModels(ICodeSearchController host, FileEntryViewModel parent, FileSystemEntryData data) {
      var positionsData = data as FilePositionsData;
      if (positionsData != null)
        return positionsData.Positions.Select(x => new FilePositionViewModel(host, parent, x));

      return Enumerable.Empty<TreeViewItemViewModel>();
    }
        public static IEnumerable <TreeViewItemViewModel> CreateViewModels(ISourceExplorerViewModelHost host, FileEntryViewModel parent, FileSystemEntryData data)
        {
            var positionsData = data as FilePositionsData;

            if (positionsData != null)
            {
                return(positionsData.Positions.Select(x => new FilePositionViewModel(host, parent, x)));
            }

            return(Enumerable.Empty <TreeViewItemViewModel>());
        }