/// <summary>
/// Liest die Daten für die Anzeige der Seite aus der Datenbank.
/// </summary>
/// <param name="token"></param>
/// <returns></returns>
private async Task InitializeAsync(Token token)
{
Token = token ?? throw new ArgumentNullException(nameof(token));
// Die angemeldeten Fächer des Users auslesen
var subjectRegistrations = from r in _context.Registrations
where r.TokenId == token.TokenId
select new SubjectRegistration
{
SubjectId = r.SubjectId,
SubjectName = r.Subject.Name,
RegistrationId = r.RegistrationId,
Rating = r.Rating
};
if (!subjectRegistrations.Any())
{
// Wenn keine Anmeldung besteht, wird eine leere Anmeldung für jedes vorhandene
// Fach erstellt.
subjectRegistrations = from s in _context.Subjects
select new SubjectRegistration
{
SubjectId = s.SubjectId,
SubjectName = s.Name
};
}
RegistrationStats = await(from r in _context.Registrations
where r.Rating == 1
group r by r.Subject.SubjectId into g
orderby g.Key
select new RegistrationStat
{
SubjectId = g.Key,
RegistrationCount = g.Count()
}).ToListAsync();
SubjectRegistrations = new SubjectRegistrationList(await subjectRegistrations.ToListAsync());
}
/// <summary>
/// Speichert die Formulareingaben in der Datenbank.
/// </summary>
/// <param name="id">Token</param>
/// <param name="subjectRegistrations">Formulardaten, die gespeichert werden müssen.</param>
/// <returns></returns>
public async Task <IActionResult> OnPostAsync(string id, SubjectRegistrationList subjectRegistrations)
{
// Nur mit gültigem Token verarbeiten.
var token = _context.Tokens.Find(id);
if (token == null)
{
return(NotFound());
}
// Die restlichen Daten für die Anzeige (Statistik) nachladen, denn es werden nur die
// Formulardaten übermittelt.
if (ModelState.IsValid)
{
foreach (var r in subjectRegistrations ?? Enumerable.Empty <SubjectRegistration>())
{
if (r.RegistrationId == 0)
{
_context.Registrations.Add(new Registration
{
SubjectId = r.SubjectId,
TokenId = id,
Rating = r.Rating
});
}
else
{
var registration = _context.Registrations.Find(r.RegistrationId);
registration.Rating = r.Rating;
}
}
_context.SaveChanges();
token.LastValidRegistration = DateTime.UtcNow;
_context.SaveChanges();
}
await InitializeAsync(token);
return(Page());
}
