Untis-API Optimierung.

LehrerApp.Desktop/ViewModels/Groups/WebUntisAbsenceComparisonViewModel.cs

@@ -1,4 +1,3 @@
-using System.Collections.Concurrent;
 using System.Collections.ObjectModel;
 using CommunityToolkit.Mvvm.ComponentModel;
 using CommunityToolkit.Mvvm.Input;
@@ -60,16 +59,14 @@ public partial class WebUntisAbsenceComparisonViewModel : ObservableObject
             var localSessions = _sessions.GetByGroup(_group.Id)
                 .Where(x => x.Date >= start && x.Date <= end).GroupBy(x => x.Date)
                 .ToDictionary(x => x.Key, x => x.First());
-            var loaded = new ConcurrentBag<(Student Student, UntisStudentAbsenceDto Absence)>();
             var linked = courseStudents.Select(student => (Student: student, Key: StudentKey(student)))
-                .Where(x => x.Key is not null).ToList();
-            await Parallel.ForEachAsync(linked, new ParallelOptions { MaxDegreeOfParallelism = 4 }, async (item, token) =>
-            {
-                var report = await _untis.GetAbsencesAsync(item.Key!.Value, start, end, token);
-                foreach (var absence in report.Absences) loaded.Add((item.Student, absence));
-            });
+                .Where(x => x.Key is not null).ToDictionary(x => x.Key!.Value, x => x.Student);
+            var absences = await _untis.GetAbsencesAsync(start, end);
+            var loaded = absences.Where(absence => linked.ContainsKey(absence.StudentKey))
+                .Select(absence => (Student: linked[absence.StudentKey], Absence: absence))
+                .OrderBy(x => x.Absence.Date).ThenBy(x => x.Student.FullName);
 
-            foreach (var item in loaded.OrderBy(x => x.Absence.Date).ThenBy(x => x.Student.FullName))
+            foreach (var item in loaded)
             {
                 if (!TryDate(item.Absence.Date, out var date)) continue;
                 localSessions.TryGetValue(date, out var session);