// GET: Instructors
public ActionResult Index(int?id, int?courseID) //id --- instructor
{
var viewModel = new InstructorsData();
//Query
//inner join
//Eager loading
viewModel.Instructors = db.Instructors
.Include(i => i.OfficeAssignment)
//.Include(i => i.Courses.Select(c => c.Department))-----navigate mesw ths class course na parw to Department
.OrderBy(i => i.LastName);
if (id != null)
{
ViewBag.InstructorID = id.Value;
viewModel.Courses = viewModel.Instructors //Ta Courses Tha ta ferei logw "Lazy-Loading" epeidh tou zhththikan
.Where(i => i.ID == id.Value).Single().Courses; //single tha ferei ena instructors apo th list viewmodel.Instuctors pou epilexame
//tha gemisei thn list apo courses gia enan Instructors
}
if (courseID != null)
{
ViewBag.CourseID = courseID.Value;
//Lazy Loading
viewModel.Enrollments = viewModel.Courses //Ta Enrollments Tha ta ferei logw "Lazy-Loading" epeidh tou zhththikan
.Where(c => c.CourseID == courseID).Single().Enrollments;
////1h epilogh Lazy
//2h Eager
//Advanced texnikh Explicit
//Explicit Loading----eite collection(lexh)eite load(lexh)---ayta pou xreiazomai akrivws----
//var selectedCourse = viewModel.Courses
// .Where(x => x.CourseID == courseID).Single();
//db.Entry(selectedCourse).Collection(x => x.Enrollments).Load(); //collection ta polla gia ena to load
//foreach (Enrollment enrollment in selectedCourse.Enrollments)
//{
// db.Entry(enrollment).Reference(x => x.Student).Load(); //reference ena tha parw
//}
//viewModel.Enrollments = selectedCourse.Enrollments;
}
return(View(viewModel));
}
// GET: Instructors
public ActionResult Index(int?id, int?courseID)
{
var viewModel = new InstructorsData();
// eager Loading
viewModel.Instructors = db.Instructors
.Include(i => i.OfficeAssignment)
//.(i => i.Courses.Select(c => c.Department))
.OrderBy(i => i.Lastname);
if (id != null)
{
ViewBag.InstructorID = id.Value;
viewModel.Courses = viewModel.Instructors
.Where(i => i.ID == id.Value).Single().Courses;
}
if (courseID != null)
{
ViewBag.CourseID = courseID.Value;
// Lazy Loading
viewModel.Enrollments = viewModel.Courses
.Where(c => c.CourseID == courseID).Single().Enrollments;
// Explicit Loading
//var selectedCourse = viewModel.Courses
// .Where(x => x.CourseID == courseID).Single();
//db.Entry(selectedCourse).Collection(x => x.Enrollments).Load();
//foreach (Enrollment enrollment in selectedCourse.Enrollments)
//{
// db.Entry(enrollment).Reference(x => x.Student).Load();
//}
//viewModel.Enrollments = selectedCourse.Enrollments;
}
return(View(viewModel));
}