public async Task <CourseVm> GetCourseById(int id)
{
Course courseEntity = await _dbContext.Courses.SingleAsync(x => x.Id == id);
CourseVm courseVm = CourseVm.FromEntity(courseEntity);
return(courseVm);
}
public async Task <IEnumerable <CourseVm> > GetAllCourses()
{
IEnumerable <Course> courseEntities = await _dbContext.Courses.ToListAsync();
IEnumerable <CourseVm> courseVms = courseEntities.Select(x => CourseVm.FromEntity(x));
return(courseVms);
}
/// <summary>
/// Get course details with students that are enrolled in this course.
/// </summary>
public async Task <CourseVm> GetCourseWithStudents(int courseId)
{
Course courseEntity = await _dbContext.Courses.
Include(x => x.Students).
SingleAsync(x => x.Id == courseId);
CourseVm courseVm = CourseVm.FromEntity(courseEntity);
return(courseVm);
}
/// <summary>
/// Get course details with students that aren't enrolled in this course.
/// </summary>
public async Task <CourseVm> GetCourseWithStudentsToAdd(int courseId)
{
Course courseEntity = await _dbContext.Courses.
Include(x => x.Students).
SingleOrDefaultAsync(x => x.Id == courseId);
// Exclude students that are already enrolled in this course.
IList <int> studentToExcludeIds = courseEntity.Students.Select(x => x.Id).ToList();
IList <Student> studentsToAdd = await _dbContext.Students.
Where(x => studentToExcludeIds.Contains(x.Id) == false).
ToListAsync();
// Course class is used as "add student model". Students property has different meaning. It represents students that currently aren't enrolled in course - potential course candidates.
// Replace enrolled students with course candidates.
courseEntity.Students = studentsToAdd;
CourseVm addStudentVm = CourseVm.FromEntity(courseEntity);
return(addStudentVm);
}