public async Task <ActionResult <Course> > PostCourse(CoursePostDTO course)
{
var enrollments = new List <Enrollment>();
var newCourse = new Course
{
Title = course.Title,
CourseId = course.CourseId,
Subject = course.Department,
TeacherId = course.TeacherAssigned.Id,
CourseLevel = course.CourseLevel
};
context.Courses.Add(newCourse);
await context.SaveChangesAsync();
foreach (var student in course.EnrolledStudents)
{
enrollments.Add(new Enrollment
{
StudentId = student.Id,
CourseId = newCourse.Id
});
}
context.Enrollments.AddRange(enrollments);
await context.SaveChangesAsync();
return(CreatedAtAction("GetCourse", new { id = newCourse.Id }, course));
}
public async Task <IActionResult> PutCourse(int id, CoursePostDTO course)
{
if (!CourseExists(id))
{
return(NotFound());
}
// get course by id and update values
var existingCourse = context.Courses.Find(id);
existingCourse.Title = course.Title;
existingCourse.CourseId = course.CourseId;
existingCourse.Subject = course.Department;
existingCourse.Teacher = course.TeacherAssigned;
existingCourse.CourseLevel = course.CourseLevel;
// get all enrollments for this course in db
var enrollments = await context.Enrollments
.Where(e => e.CourseId == id)
.ToListAsync();
var previousStudentIds = enrollments.Select(e => e.StudentId).ToList();
var currentStudentIds = course.EnrolledStudents.Select(s => s.Id).ToList();
// remove all enrollments that aren't in new list
var enrollmentsToRemove = enrollments
.Where(e => !currentStudentIds.Contains(e.StudentId))
.ToList();
context.Enrollments.RemoveRange(enrollmentsToRemove);
// add new enrollments that did not exist
var studentsToEnroll = course.EnrolledStudents
.Where(s => !previousStudentIds.Contains(s.Id))
.ToList();
var newEnrollments = new List <Enrollment>();
foreach (var student in studentsToEnroll)
{
newEnrollments.Add(
new Enrollment
{
StudentId = student.Id,
CourseId = existingCourse.Id
});
}
context.Enrollments.AddRange(newEnrollments);
try
{
await context.SaveChangesAsync();
}
catch (DbUpdateConcurrencyException)
{
if (!CourseExists(id))
{
return(NotFound());
}
else
{
throw;
}
}
return(NoContent());
}