public async Task <IActionResult> OnPostAsync(int id)
{
if (!ModelState.IsValid)
{
return(Page());
}
var departmentToUpdate = await _context.Departments
.Include(i => i.Administrator)
.FirstOrDefaultAsync(m => m.DepartmentID == id);
if (departmentToUpdate == null)
{
return(HandleDeletedDepartment());
}
_context.Entry(departmentToUpdate)
.Property("RowVersion").OriginalValue = Department.RowVersion;
if (await TryUpdateModelAsync <Department>(
departmentToUpdate,
"Department",
s => s.Name, s => s.StartDate, s => s.Budget, s => s.InstructorID))
{
try
{
await _context.SaveChangesAsync();
return(RedirectToPage("./Index"));
}
catch (DbUpdateConcurrencyException ex)
{
var exceptionEntry = ex.Entries.Single();
var clientValues = (Department)exceptionEntry.Entity;
var databaseEntry = exceptionEntry.GetDatabaseValues();
if (databaseEntry == null)
{
ModelState.AddModelError(string.Empty, "Unable to save. " +
"The department was deleted by another user.");
return(Page());
}
var dbValues = (Department)databaseEntry.ToObject();
await setDbErrorMessage(dbValues, clientValues, _context);
// Save the current RowVersion so next postback
// matches unless an new concurrency issue happens.
Department.RowVersion = (byte[])dbValues.RowVersion;
// Clear the model error for the next postback.
ModelState.Remove("Department.RowVersion");
}
}
InstructorNameSL = new SelectList(_context.Instructors,
"ID", "FullName", departmentToUpdate.InstructorID);
return(Page());
}
public async Task OnGetAsync(int?id, int?CourseID)
{
//Instructor = await _context.Instructors.ToListAsync();
InstructorData = new InstructorIndexData();
InstructorData.Instructors = await _context.Instructors
.Include(i => i.OfficeAssignment)
.Include(i => i.CourseAssignments)
.ThenInclude(i => i.Course)
.ThenInclude(i => i.Department)
/*
* This was added for eager loading, however, if the user barely need to look at enrolment, we could delegate the query until user selects it
*/
//.Include(i => i.CourseAssignments)
// .ThenInclude(i => i.Course)
// .ThenInclude(i => i.Enrollments)
// .ThenInclude(i => i.Student)
//.AsNoTracking()
.OrderBy(i => i.LastName)
.ToListAsync();
/*
* The filters will return a collection of a single item
* .Single() converts that to a single Instructor/Course entity
* - will complain if the collection is empty though
* .SingleOrDefault() will return null if the collection is empty
*/
if (id != null)
{
InstructorID = id.Value;
/*
* .Where(cond).Single() or .Single(cond) are equivalent
*/
//Instructor instructor = InstructorData.Instructors.Where(i => i.ID == id.Value).Single();
Instructor instructor = InstructorData.Instructors.Single(i => i.ID == id.Value);
InstructorData.Courses = instructor.CourseAssignments.Select(s => s.Course);
}
if (CourseID != null)
{
this.CourseID = CourseID.Value;
var selectedCourse = InstructorData.Courses
.Where(s => s.CourseID == CourseID.Value)
.Single();
/*
* Added this to only load enrolment details when clicked
*/
await _context.Entry(selectedCourse).Collection(x => x.Enrollments).LoadAsync();
foreach (Enrollment en in selectedCourse.Enrollments)
{
await _context.Entry(en).Reference(x => x.Student).LoadAsync();
}
InstructorData.Enrollments = selectedCourse.Enrollments;
}
}
