public async Task <IActionResult> EnrollStudents(int?id)
{
if (id == null)
{
return(NotFound());
}
var course = _context.Course.Where(c => c.Id == id).Include(c => c.FirstTeacher).Include(c => c.SecondTeacher)
.Include(c => c.Students).ThenInclude(c => c.Student).First();
if (course == null)
{
return(NotFound());
}
CoursesEnrollStudentsClass viewmodel = new CoursesEnrollStudentsClass
{
Course = course,
StudentList = new MultiSelectList(_context.Student.OrderBy(s => s.FirstName), "Id", "FirstName"),
SelectedStudents = course.Students.Select(s => s.StudentId)
};
ViewData["FirstTeacherId"] = new SelectList(_context.Set <Teacher>(), "Id", "FirstName", viewmodel.Course.FirstTeacherId);
ViewData["SecondTeacherId"] = new SelectList(_context.Set <Teacher>(), "Id", "FirstName", viewmodel.Course.SecondTeacherId);
return(View(viewmodel));
}
public async Task <IActionResult> EnrollStudents(int id, int inputYear, string inputSemester, CoursesEnrollStudentsClass viewmodel)
{
if (id != viewmodel.Course.Id)
{
return(NotFound());
}
if (ModelState.IsValid)
{
try
{
await _context.SaveChangesAsync();
IEnumerable <int> listStudents = viewmodel.SelectedStudents;
IQueryable <Enrollment> toBeRemoved = _context.Enrollment.Where(s => !listStudents.Contains(s.StudentId) &&
s.CourseId == id).Include(s => s.Course).Include(s => s.Student);
_context.Enrollment.RemoveRange(toBeRemoved);
IEnumerable <int> existStudents = _context.Enrollment.Where(s => listStudents.Contains(s.StudentId)
&& s.CourseId == id).Include(s => s.Course).Include(s => s.Student)
.Select(s => s.StudentId);
IEnumerable <int> newStudents = listStudents.Where(s => !existStudents.Contains(s));
foreach (int studentId in newStudents)
{
_context.Enrollment.Add(new Enrollment {
StudentId = studentId, CourseId = id, Year = inputYear, Semester = inputSemester
});
}
_context.Update(viewmodel.Course);
await _context.SaveChangesAsync();
}
catch (DbUpdateConcurrencyException)
{
if (!CourseExists(viewmodel.Course.Id))
{
return(NotFound());
}
else
{
throw;
}
}
return(RedirectToAction(nameof(Index)));
}
ViewData["FirstTeacherId"] = new SelectList(_context.Set <Teacher>(), "Id", "FirstName", viewmodel.Course.FirstTeacherId);
ViewData["SecondTeacherId"] = new SelectList(_context.Set <Teacher>(), "Id", "FirstName", viewmodel.Course.SecondTeacherId);
return(View(viewmodel));
}