public string VerifyTime(Consulting consulting) { var nextHour = consulting.StartConsulting.AddHours(1); var preHour = consulting.StartConsulting.AddHours(-1); var notAllow = _consultingRepository.GetAll().Where(c => ((c.StartConsulting > preHour && c.StartConsulting <= consulting.StartConsulting && c.ConsultingId != consulting.ConsultingId) || (c.StartConsulting > consulting.StartConsulting && c.StartConsulting < nextHour && c.ConsultingId != consulting.ConsultingId)) && c.DoctorId.Equals(consulting.DoctorId)) .ToList(); if (notAllow.Count > 0) { var result = ""; foreach (var item in notAllow) { result += item.StartConsulting.ToString("dd/MM/yyyy HH:mm"); } return(result); } return(null); }