public IActionResult OnPost() { if (ModelState.IsValid) { foreach (var symptom in Symptoms) { if (symptom.IsSelected) { Virus.VirusSymptoms.Add(new VirusSymptom { Symptom = symptomService.GetSymptomById(symptom.Id) }); } } if (Virus.Id == 0) { virusService.CreateVirus(Virus); } else { var virus = virusService.GetVirusById(Virus.Id); virusService.RemoveVirus(virus.Id); virusService.CreateVirus(Virus); } virusService.Commit(); return(RedirectToPage("./VirusList")); } Symptoms = symptomService.GetSymptoms(); return(Page()); }