public async Task <IActionResult> OnGetAsync(Guid id) { Instructor = await _instructorRepository.GetInstructorAsync(id); if (Instructor == null) { return(NotFound()); } CourseAssignments = new CourseAssignmentViewModel() { InstructorId = id }; var assignedCourses = await _instructorRepository.GetAssignedCourseData(id); var allCourses = await _courseRepository.GetCoursesAndDepartmentsAsync(); var checkBoxListItems = allCourses .Select(course => new CheckBoxListItem { Id = course.Id, Display = course.Title, IsChecked = assignedCourses.Any(x => x.CourseId == course.Id) }).ToList(); CourseAssignments.AssignedCourses = checkBoxListItems; return(Page()); }