public static Boolean SendNotificationToUser(NotificationUser notification, int userID)
        {
            try
            {
                using (var db = new DBContextModel())
                {
                    TblNotifications notif = new TblNotifications
                    {
                        Description = notification.Description,
                        Hour        = DateTime.Now,
                        Subject     = notification.Subject,
                        Urgency     = notification.Urgency,
                        Approval    = notification.Approval,
                        UserFK      = notification.SenderFK
                    };
                    db.TblNotifications.Add(notif);
                    db.SaveChanges();

                    TblValidations valid = new TblValidations
                    {
                        NotificationFK = notif.ID,
                        ReceiverFK     = notification.ReceiverFK,
                        Accepted       = false,
                        Read           = false,
                        StudentFK      = notification.StudentFK
                    };
                    db.TblValidations.Add(valid);
                    db.SaveChanges();

                    BAction.SetActionToUser(String.Format("enviou uma notificação ao utilizador '{0}'", db.TblUsers.Find(notification.ReceiverFK).Name), userID);
                    return(true);
                }
            }
            catch (Exception) { return(false); }
        }
        public static Boolean SendNotificationToClass(NotificationClass notification, int userID)
        {
            try
            {
                using (var db = new DBContextModel())
                {
                    TblNotifications notif = new TblNotifications
                    {
                        Description = notification.Description,
                        Hour        = DateTime.Now,
                        Subject     = notification.Subject,
                        Urgency     = notification.Urgency,
                        Approval    = notification.Approval,
                        UserFK      = notification.SenderFK
                    };
                    db.TblNotifications.Add(notif);
                    db.SaveChanges();

                    var students = BClass.GetStudentsByClass(notification.ClassFK);
                    foreach (var student in students)
                    {
                        TblValidations valid = new TblValidations
                        {
                            ReceiverFK = BParenting.GetGuardians(student).FirstOrDefault(),
                            StudentFK  = student,
                            Accepted   = false,
                            Read       = false
                        };
                        db.TblValidations.Add(valid);
                        db.SaveChanges();
                    }

                    var cla = db.TblClasses.Find(notification.ClassFK);
                    BAction.SetActionToUser(String.Format("enviou uma notificação a turma '{0}'", cla.Year + cla.ClassDesc), userID);
                    return(true);
                }
            }
            catch (Exception) { return(false); }
        }