public string GetChangeList(int fileId, int?count, int?page) { if (!User.Identity.IsAuthenticated) { return("null"); } int cnt, pg; if (!count.HasValue || !page.HasValue) { cnt = 10; pg = 1; } else { cnt = count.Value; pg = page.Value; } List <Changes> result; if (User.IsInRole("Admin")) { result = _context.GetAdminChangeList(fileId, cnt, pg); } else { result = _context.GetUserChangeList(fileId, User.Identity.Name, cnt, pg); } if (result.Count == 0) { return("null"); } else { result.ForEach(res => res.File = null); return(JsonConvert.SerializeObject(result, JsonSettings)); } }