public void Navigate(NavigationWindowView frame, string command)
        {
            switch (command)
            {
            case "menuLogo":
                if (activeUser.Type == UserType.Teacher)
                {
                    window.DetailFrame.Content = new TeacherView(activeUser);
                }
                else if (activeUser.Type == UserType.Admin)
                {
                    window.DetailFrame.Content = new AdminView(activeUser);
                }
                break;

            case "btnSeeQuizzes":
                window.DetailFrame.Content = new Statistics();
                break;

            case "btnCreateQuiz":
                window.DetailFrame.Content = new CreateQuiz(activeUser);
                break;

            case "btnSendQuiz":
                window.DetailFrame.Content = new SendQuiz(activeUser);
                break;

            case "btnAdministrate":
                window.DetailFrame.Content = new AddRemoveUsers();
                break;

            default:
                break;
            }
        }
        public void RenderAccessibility(User user, NavigationWindowView window)
        {
            this.window = window;
            activeUser  = user;
            switch (user.Type)
            {
            case UserType.Teacher:
                window.btnSendQuiz.Visibility     = Visibility.Collapsed;
                window.btnAdministrate.Visibility = Visibility.Collapsed;
                window.DetailFrame.Content        = new TeacherView(activeUser);
                break;

            case UserType.Admin:
                window.btnCreateQuiz.Visibility = Visibility.Collapsed;
                window.DetailFrame.Content      = new AdminView(activeUser);
                break;

            //case UserType.Student:
            //    //throw new ArgumentException("User is student - no acessibility should be allowed in this program");
            default:
                break;
            }
        }