public TimeSpan TimeStuck(Patient patient) { var p = PatientsList.FirstOrDefault(x => x.Id == patient.Id); var index = PatientsList.IndexOf(p); if (index == -1) { return(TimeSpan.Zero); } if (index == 0) { return(TimeSpan.Zero); } TimeSpan duration; for (var i = 0; i < index; i++) { duration += PatientsList[i].Duration; } return(duration); //patient.VisitTime.Subtract(DateTime.Now) <= duration; }