public IActionResult SaveEntry(string group, string clas, string teacher, string room, int?slot, string day) { if (String.IsNullOrEmpty(room) || String.IsNullOrEmpty(day) || !slot.HasValue || String.IsNullOrEmpty(group) || String.IsNullOrEmpty(clas) || String.IsNullOrEmpty(teacher)) { return(RedirectToAction(nameof(Index))); } plannerData.AddActivity(room, slot.Value, day, group, clas, teacher); return(RedirectToAction("Index", new { room = room })); }