private async Task AddCourses()
        {
            var viewModel = new CoursesDetailViewModel(new CoursesTableViewModel(), _coursesStore, _pageService);

            viewModel.CourseAdded += (source, course) =>
            {
                Courses.Add(new CoursesTableViewModel(course));
            };

            await _pageService.PushModalAsync(new CoursesDetailPage(viewModel));
        }
        private async Task SelectCourses(CoursesTableViewModel courses)
        {
            if (courses == null)
            {
                return;
            }

            SelectedCourse = null;

            var viewModel = new CoursesDetailViewModel(courses, _coursesStore, _pageService);

            viewModel.CourseUpdated += (source, updateCourse) =>
            {
                courses.Id         = updateCourse.id;
                courses.CourseID   = updateCourse.courseID;
                courses.CourseName = updateCourse.courseName;
                courses.StaffID    = updateCourse.staffID;
                courses.Fee        = updateCourse.fee;
            };

            await _pageService.PushModalAsync(new CoursesDetailPage(viewModel));
        }