public async Task OnGetAsync(int?id, int?courseID)
{
InstructorData = new InstructorIndexData();
InstructorData.Instructors = await _context.Instructors
.Include(i => i.OfficeAssignment)
.Include(i => i.CourseAssignments).ThenInclude(ca => ca.Course).ThenInclude(c => c.Department)
.OrderBy(i => i.LastName)
.ToListAsync();
if (id != null)
{
InstructorID = id.Value;
var selectedInstructor = InstructorData.Instructors.Single(i => i.ID == InstructorID);
InstructorData.Courses = selectedInstructor.CourseAssignments.Select(ca => ca.Course);
}
if (courseID != null)
{
CourseID = courseID.Value;
var selectedCourse = InstructorData.Courses.Where(c => c.CourseID == courseID).Single();
await _context.Entry(selectedCourse).Collection(c => c.Enrollments).LoadAsync();
foreach (var enrollment in selectedCourse.Enrollments)
{
await _context.Entry(enrollment).Reference(e => e.Student).LoadAsync();
}
InstructorData.Enrollments = selectedCourse.Enrollments;
}
}
public async Task OnGetAsync(int?id, int?courseID)
{
//Безотложная загрузка свойств навигации
/* методы Include и ThenInclude повторяются для CourseAssignments и Course.
* Это необходимо для того, чтобы задать безотложную загрузку для двух свойств навигации сущности Course.
*/
InstructorData = new InstructorIndexData();
InstructorData.Instructors = await _context.Instructors
.Include(i => i.OfficeAssignment)
.Include(i => i.CourseAssignments)
.ThenInclude(i => i.Course)
.ThenInclude(i => i.Department)
/* Предположим, что пользователям редко требуется просматривать зачисления на курс.
* В этом случае можно оптимизировать работу, загружая данные о зачислении только при их запросе.
* Тогда комментируем это фрагментю и добавляем явную занрузку курсов
* .Include(i => i.CourseAssignments)
* .ThenInclude(i => i.Course)
* .ThenInclude(i => i.Enrollments)
* .ThenInclude(i => i.Student)*/
//.AsNoTracking() -- для подклчения явной занрузки трекинг должен бытьвключен
.OrderBy(i => i.LastName)
.ToListAsync();
if (id != null)
{
/* Из свойства навигации CourseAssignments этого преподавателя
* загружается свойство модели представления Courses вместе с сущностями Course.
*/
InstructorID = id.Value;
Instructor instructor = InstructorData.Instructors
.Where(i => i.ID == id.Value).Single();
InstructorData.Courses = instructor.CourseAssignments.Select(s => s.Course);
}
if (courseID != null)
{
CourseID = courseID.Value;
var selectedCourse = InstructorData.Courses
.Where(x => x.CourseID == courseID).Single();
//---------------- Явная загрузка курсов -------------------------
await _context.Entry(selectedCourse).Collection(x => x.Enrollments).LoadAsync();
foreach (Enrollment enrollment in selectedCourse.Enrollments)
{
await _context.Entry(enrollment).Reference(x => x.Student).LoadAsync();
}
//---------------- end: Явная загрузка курсов --------------------
InstructorData.Enrollments = selectedCourse.Enrollments;
}
}
public async Task OnGetAsync(int?id, int?courseID)
{
InstructorData = new InstructorIndexData();
InstructorData.Instructors = await _context.Instructors
.Include(i => i.OfficeAssignment)
.Include(i => i.CourseAssignments)
.ThenInclude(i => i.Course)
.ThenInclude(i => i.Department)
// ** Eager Loading
//.Include(i => i.CourseAssignments)
// .ThenInclude(i => i.Course)
// .ThenInclude(i => i.Enrollments)
// .ThenInclude(i => i.Student)
//.AsNoTracking()
.OrderBy(i => i.LastName)
.ToListAsync();
if (id != null)
{
InstructorID = id.Value;
Instructor instructor = InstructorData.Instructors
.Where(i => i.ID == id.Value).Single();
InstructorData.Courses = instructor.CourseAssignments.Select(s => s.Course);
}
if (courseID != null)
{
CourseID = courseID.Value;
var selectedCourse = InstructorData.Courses
.Where(x => x.CourseID == courseID).Single();
// ** Explicit loading
await _context.Entry(selectedCourse).Collection(x => x.Enrollments).LoadAsync();
foreach (Enrollment enrollment in selectedCourse.Enrollments)
{
await _context.Entry(enrollment).Reference(x => x.Student).LoadAsync();
}
InstructorData.Enrollments = selectedCourse.Enrollments;
}
}
public async Task OnGetAsync(int?id, int?courseID)
{
#region snippet_query
InstructorData = new InstructorIndexData();
InstructorData.Instructors = await _context.Instructors
.Include(i => i.OfficeAssignment)
.Include(i => i.Courses)
.ThenInclude(c => c.Department)
.OrderBy(i => i.LastName)
.ToListAsync();
#endregion
#region snippet_id
if (id != null)
{
InstructorID = id.Value;
Instructor instructor = InstructorData.Instructors
.Where(i => i.ID == id.Value).Single();
InstructorData.Courses = instructor.Courses;
}
#endregion
#region snippet_enrollment
if (courseID != null)
{
CourseID = courseID.Value;
var selectedCourse = InstructorData.Courses
.Where(x => x.CourseID == courseID).Single();
await _context.Entry(selectedCourse)
.Collection(x => x.Enrollments).LoadAsync();
foreach (Enrollment enrollment in selectedCourse.Enrollments)
{
await _context.Entry(enrollment).Reference(x => x.Student).LoadAsync();
}
InstructorData.Enrollments = selectedCourse.Enrollments;
}
#endregion
}
public async Task OnGetAsync(int?id, int?courseID)
{
CoachData = new CoachIndexData();
CoachData.Coaches = await _context.Coaches
.Include(i => i.OfficeAssignment)
.Include(i => i.TeamAssignments)
.ThenInclude(i => i.Team)
.ThenInclude(i => i.Department)
//.Include(i => i.CourseAssignments)
// .ThenInclude(i => i.Course)
// .ThenInclude(i => i.Enrollments)
// .ThenInclude(i => i.Student)
//.AsNoTracking()
.OrderBy(i => i.LastName)
.ToListAsync();
if (id != null)
{
CoachID = id.Value;
Coach coach = CoachData.Coaches
.Where(i => i.ID == id.Value).Single();
CoachData.Teams = coach.TeamAssignments.Select(s => s.Team);
}
if (courseID != null)
{
TeamID = courseID.Value;
var selectedCourse = CoachData.Teams
.Where(x => x.TeamID == courseID).Single();
await _context.Entry(selectedCourse).Collection(x => x.Contracts).LoadAsync();
foreach (Contract enrollment in selectedCourse.Contracts)
{
await _context.Entry(enrollment).Reference(x => x.Player).LoadAsync();
}
CoachData.Contracts = selectedCourse.Contracts;
}
}