public async Task <ComicNavigationVM> GetComicNavigationById(int?comicId) { if (comicId == null) { return new ComicNavigationVM { NextId = null, PreviousId = null, FirstId = null, LastId = null } } ; return(new ComicNavigationVM { PreviousId = await _comicRepository.GetPreviousComicId(comicId.Value), NextId = await _comicRepository.GetNextComicId(comicId.Value), FirstId = await _comicRepository.GetFirstComicId(), LastId = await _comicRepository.GetLastComicId() }); }