public async Task <DbCourse> CreateCourseAsync(DbCourse course)
{
if (course == null || course.Id != 0)
{
return(null);
}
_context.Courses.Add(course);
await _context.SaveChangesAsync();
return(course);
}
public async Task <DbEnrollment> EnrollCourseAsync(DbEnrollment enrollment)
{
DbEnrollment existingEnrollment = _context.Enrollments
.Where(e => e.CourseId == enrollment.CourseId && e.UserId == enrollment.UserId)
.SingleOrDefault();
if (existingEnrollment != null)
{
return(null);
}
_context.Enrollments.Add(enrollment);
await _context.SaveChangesAsync();
DbEnrollment newEnrollment = await _context.Enrollments
.Where(e => e.CourseId == enrollment.CourseId && e.UserId == enrollment.UserId)
.SingleOrDefaultAsync();
return(newEnrollment);
}