feat: add seating plan drag and quick assessment

LehrerApp.Data.Tests/RepositoryTests.cs

@@ -299,6 +299,38 @@ public sealed class RepositoryTests
         Assert.Throws<InvalidOperationException>(() => new SeatingPlanRepository(db).Save(plan));
     }
 
+    [Fact]
+    public void SeatingPlanRepository_AktualisiertPlanMitFehlendemOptionalenRaum()
+    {
+        using var db = NewInMemoryContext();
+        var group = new LearningGroup { Name = "8a", SchoolYear = "2025/26" };
+        new GroupRepository(db).Save(group);
+        var student = new Student { FirstName = "Anna", LastName = "A" };
+        db.Students.Insert(student);
+        db.Memberships.Insert(new GroupMembership { GroupId = group.Id, StudentId = student.Id });
+        var plan = new SeatingPlan
+        {
+            GroupId = group.Id,
+            Name = "Standard",
+            Room = null!,
+            Rows = 2,
+            Columns = 2,
+        };
+        db.SeatingPlans.Insert(plan);
+        plan.Assignments.Add(new SeatAssignment { Row = 0, Column = 0, StudentId = student.Id });
+
+        new SeatingPlanRepository(db).Save(plan);
+
+        var saved = db.SeatingPlans.FindById(plan.Id);
+        Assert.NotNull(saved);
+        Assert.True(string.IsNullOrEmpty(saved.Room));
+        Assert.Equal(student.Id, saved.Assignments.Single().StudentId);
+
+        // LiteDB may materialize the empty optional value as null again. A later
+        // drag/drop save must therefore remain safe as well.
+        new SeatingPlanRepository(db).Save(saved);
+    }
+
     [Fact]
     public void GroupMembershipRepository_Save_LehntZweiteZuordnungFuerGleichesPaarAb()
     {

LehrerApp.Data/Repositories/AllRepositories.cs

@@ -162,8 +162,11 @@ public class SeatingPlanRepository(LiteDbContext db) : ISeatingPlanRepository
     public void Save(SeatingPlan plan)
     {
         ArchivedGroupWriteGuard.EnsureActive(db, plan.GroupId);
-        plan.Name = plan.Name.Trim();
+        // LiteDB can deserialize missing/legacy optional string fields as null even
-        plan.Room = plan.Room.Trim();
+        // though the current model initializes them with an empty string.
+        plan.Name = plan.Name?.Trim() ?? "";
+        plan.Room = plan.Room?.Trim() ?? "";
+        plan.Assignments ??= [];
         if (plan.Name.Length == 0)
             throw new ArgumentException("Der Name des Sitzplans darf nicht leer sein.");
         if (plan.Rows is < 1 or > 10 || plan.Columns is < 1 or > 10)

LehrerApp.Desktop.Tests/Fakes.cs

@@ -78,8 +78,12 @@ public class FakeSessions(List<ParticipationSession> all) : IParticipationSessio
 {
     public List<ParticipationSession> GetByGroup(Guid groupId) => all.Where(s => s.GroupId == groupId).ToList();
     public ParticipationSession? GetById(Guid id) => all.FirstOrDefault(s => s.Id == id);
-    public void Save(ParticipationSession session) { }
+    public void Save(ParticipationSession session)
-    public void Delete(Guid id) { }
+    {
+        all.RemoveAll(s => s.Id == session.Id);
+        all.Add(session);
+    }
+    public void Delete(Guid id) => all.RemoveAll(s => s.Id == id);
 }
 
 public class FakeEntries : IParticipationRepository

LehrerApp.Desktop.Tests/GroupDetailViewModelTests.cs

@@ -25,7 +25,8 @@ public sealed class GroupDetailViewModelTests
                 new FakeCompetencyDomains(), TestSupport.BuildAiSettingsService()),
             new CompetencyOverviewTabViewModel(new FakeUnits(), exams, new FakeResults(),
                 new FakeCompetencyDomains(), students, new CompetencyAnalysisService()),
-            new SeatingPlanTabViewModel(new FakeSeatingPlans(), students, memberships));
+            new SeatingPlanTabViewModel(new FakeSeatingPlans(), students, memberships,
+                new FakeSessions([]), new FakeEntries(), new FakeAspects()));
 
         vm.LoadGroup(group.Id);
         vm.SelectedExam = vm.Exams.First(e => e.Id == exam.Id);

LehrerApp.Desktop.Tests/SeatingPlanViewModelTests.cs

@@ -24,7 +24,8 @@ public sealed class SeatingPlanViewModelTests
             Assignments = [new SeatAssignment { Row = 0, Column = 0, StudentId = student.Id }],
         };
         var plans = new FakeSeatingPlans([plan]);
-        var vm = new SeatingPlanTabViewModel(plans, students, memberships);
+        var vm = new SeatingPlanTabViewModel(plans, students, memberships,
+            new FakeSessions([]), new FakeEntries(), new FakeAspects());
         vm.Initialize(groupId, isReadOnly: false);
 
         vm.Seats[1].SelectedOption = vm.StudentOptions.Single(o => o.StudentId == student.Id);
@@ -40,7 +41,8 @@ public sealed class SeatingPlanViewModelTests
         var groupId = Guid.NewGuid();
         var plan = new SeatingPlan { GroupId = groupId, Name = "Standard", Rows = 1, Columns = 1 };
         var vm = new SeatingPlanTabViewModel(
-            new FakeSeatingPlans([plan]), new FakeStudents([]), new FakeMemberships([]));
+            new FakeSeatingPlans([plan]), new FakeStudents([]), new FakeMemberships([]),
+            new FakeSessions([]), new FakeEntries(), new FakeAspects());
 
         vm.Initialize(groupId, isReadOnly: true);
 
@@ -48,4 +50,74 @@ public sealed class SeatingPlanViewModelTests
         Assert.False(vm.Seats.Single().CanEdit);
         Assert.False(vm.AddPlanCommand.CanExecute(null));
     }
+
+    [Fact]
+    public void DragDrop_ZwischenBelegtenPlaetzen_TauschtDieSchueler()
+    {
+        var groupId = Guid.NewGuid();
+        var anna = new Student { FirstName = "Anna", LastName = "A" };
+        var ben = new Student { FirstName = "Ben", LastName = "B" };
+        var students = new FakeStudents([anna, ben]);
+        var memberships = new FakeMemberships([
+            new GroupMembership { GroupId = groupId, StudentId = anna.Id },
+            new GroupMembership { GroupId = groupId, StudentId = ben.Id },
+        ]);
+        var plan = new SeatingPlan
+        {
+            GroupId = groupId, Name = "Standard", Rows = 1, Columns = 2,
+            Assignments =
+            [
+                new SeatAssignment { Row = 0, Column = 0, StudentId = anna.Id },
+                new SeatAssignment { Row = 0, Column = 1, StudentId = ben.Id },
+            ],
+        };
+        var plans = new FakeSeatingPlans([plan]);
+        var vm = new SeatingPlanTabViewModel(plans, students, memberships,
+            new FakeSessions([]), new FakeEntries(), new FakeAspects());
+        vm.Initialize(groupId, isReadOnly: false);
+
+        vm.MoveSeat(vm.Seats[0], vm.Seats[1]);
+
+        Assert.Equal(ben.Id, vm.Seats[0].SelectedOption.StudentId);
+        Assert.Equal(anna.Id, vm.Seats[1].SelectedOption.StudentId);
+        Assert.Equal(2, plans.GetById(plan.Id)!.Assignments.Count);
+    }
+
+    [Fact]
+    public void SitzplatzBewertung_ErstelltHeutigeSitzungUndSpeichertAlleDreiBereiche()
+    {
+        var groupId = Guid.NewGuid();
+        var studentId = Guid.NewGuid();
+        var sessions = new FakeSessions([]);
+        var entries = new FakeEntries();
+        var vm = new SeatAssessmentViewModel(sessions, entries, new FakeAspects(),
+            groupId, studentId, "Beispiel, Anna", canEdit: true);
+
+        vm.SetRatingByNumber(5);
+        vm.ApplyAttendanceShortcut(1, clear: false);
+        vm.ApplyHomeworkShortcut(7, clear: false);
+
+        var session = Assert.Single(sessions.GetByGroup(groupId));
+        Assert.Equal(DateOnly.FromDateTime(DateTime.Today), session.Date);
+        Assert.Equal("Sitzplan", session.Comment);
+        var entry = entries.GetBySessionAndStudent(session.Id, studentId)!;
+        Assert.Equal(2, entry.Ratings.Single(r => r.Key == "quality").Value);
+        Assert.Equal(AttendanceStatus.Present, entry.Attendance);
+        Assert.Equal(HomeworkStatus.MissingOpen, entry.Homework);
+        Assert.True(entry.HomeworkMissing);
+    }
+
+    [Fact]
+    public void SitzplatzBewertung_ArchiviertOhneSitzung_LegtKeineNeueSitzungAn()
+    {
+        var groupId = Guid.NewGuid();
+        var sessions = new FakeSessions([]);
+
+        var vm = new SeatAssessmentViewModel(sessions, new FakeEntries(), new FakeAspects(),
+            groupId, Guid.NewGuid(), "Beispiel, Anna", canEdit: false);
+        vm.SetRatingByNumber(5);
+
+        Assert.False(vm.CanEdit);
+        Assert.Empty(sessions.GetByGroup(groupId));
+    }
 }

LehrerApp.Desktop/ViewModels/Groups/GroupViewModels.cs

@@ -243,6 +243,11 @@ public partial class GroupDetailViewModel : ObservableObject
         PlanningTab = planningTab;
         CompetencyOverviewTab = competencyOverviewTab;
         SeatingPlanTab = seatingPlanTab;
+        SeatingPlanTab.OnAssessmentChanged = () =>
+        {
+            ParticipationTab.LoadSessions();
+            ParticipationTab.RefreshCurrentGrid();
+        };
     }
 
     public void LoadGroup(Guid id)

LehrerApp.Desktop/ViewModels/Groups/ParticipationViewModels.cs

@@ -108,11 +108,11 @@ public partial class ParticipationTabViewModel : ObservableObject
 
     public void LoadSessions()
     {
+        var selectedId = SelectedSession?.Id;
         Sessions.Clear();
         foreach (var s in _sessions.GetByGroup(_groupId))
             Sessions.Add(new ParticipationSessionItem(s));
-        if (SelectedSession is null && Sessions.Any())
+        SelectedSession = Sessions.FirstOrDefault(s => s.Id == selectedId) ?? Sessions.FirstOrDefault();
-            SelectedSession = Sessions[0];
     }
 
     partial void OnSelectedSessionChanged(ParticipationSessionItem? value)

LehrerApp.Desktop/ViewModels/Groups/SeatingPlanViewModels.cs

@@ -12,6 +12,9 @@ public partial class SeatingPlanTabViewModel : ObservableObject
     private readonly ISeatingPlanRepository _plans;
     private readonly IStudentRepository _students;
     private readonly IGroupMembershipRepository _memberships;
+    private readonly IParticipationSessionRepository _sessions;
+    private readonly IParticipationRepository _participation;
+    private readonly IParticipationAspectRepository _aspects;
     private Guid _groupId;
     private SeatingPlan? _currentPlan;
     private bool _isReadOnly;
@@ -25,19 +28,26 @@ public partial class SeatingPlanTabViewModel : ObservableObject
     public ObservableCollection<SeatingPlanSummary> Plans { get; } = [];
     public ObservableCollection<SeatCellViewModel> Seats { get; } = [];
     public ObservableCollection<StudentSeatOption> StudentOptions { get; } = [];
+    public ObservableCollection<StudentSeatOption> UnassignedStudents { get; } = [];
 
     public bool HasPlans => Plans.Count > 0;
     public bool HasSelectedPlan => _currentPlan is not null;
     public bool IsEditable => !_isReadOnly;
     public Func<SeatingPlan?, Task<SeatingPlan?>>? OnEditPlan { get; set; }
     public Func<SeatingPlanSummary, Task<bool>>? OnConfirmDelete { get; set; }
+    public Func<SeatAssessmentViewModel, Task>? OnAssessStudent { get; set; }
+    public Action? OnAssessmentChanged { get; set; }
 
     public SeatingPlanTabViewModel(ISeatingPlanRepository plans, IStudentRepository students,
-        IGroupMembershipRepository memberships)
+        IGroupMembershipRepository memberships, IParticipationSessionRepository sessions,
+        IParticipationRepository participation, IParticipationAspectRepository aspects)
     {
         _plans = plans;
         _students = students;
         _memberships = memberships;
+        _sessions = sessions;
+        _participation = participation;
+        _aspects = aspects;
     }
 
     public SeatingPlanDialogViewModel CreateDialogViewModel(SeatingPlan? plan) =>
@@ -87,6 +97,7 @@ public partial class SeatingPlanTabViewModel : ObservableObject
         Seats.Clear();
         if (plan is null)
         {
+            UnassignedStudents.Clear();
             PlanColumns = 1;
             PlanTitle = "";
             PlanSubtitle = "";
@@ -124,6 +135,49 @@ public partial class SeatingPlanTabViewModel : ObservableObject
                 other.SetSelectionSilently(StudentSeatOption.Empty);
         }
 
+        SaveSeatAssignments();
+    }
+
+    private void UpdateAssignmentSummary()
+    {
+        var assigned = Seats.Count(s => s.SelectedOption.StudentId.HasValue);
+        var total = StudentOptions.Count - 1;
+        AssignmentSummary = $"{assigned} von {total} Schülern zugeordnet";
+        var assignedIds = Seats.Where(s => s.SelectedOption.StudentId.HasValue)
+            .Select(s => s.SelectedOption.StudentId!.Value).ToHashSet();
+        UnassignedStudents.Clear();
+        foreach (var option in StudentOptions.Where(o => o.StudentId.HasValue && !assignedIds.Contains(o.StudentId.Value)))
+            UnassignedStudents.Add(option);
+    }
+
+    public void MoveSeat(SeatCellViewModel source, SeatCellViewModel target)
+    {
+        if (!IsEditable || source == target || !source.SelectedOption.StudentId.HasValue) return;
+        var targetOption = target.SelectedOption;
+        target.SetSelectionSilently(source.SelectedOption);
+        source.SetSelectionSilently(targetOption);
+        SaveSeatAssignments();
+    }
+
+    public void AssignStudent(StudentSeatOption student, SeatCellViewModel target)
+    {
+        if (!IsEditable || !student.StudentId.HasValue) return;
+        foreach (var other in Seats.Where(s => s != target && s.SelectedOption.StudentId == student.StudentId))
+            other.SetSelectionSilently(StudentSeatOption.Empty);
+        target.SetSelectionSilently(student);
+        SaveSeatAssignments();
+    }
+
+    public void ClearSeat(SeatCellViewModel seat)
+    {
+        if (!IsEditable || !seat.SelectedOption.StudentId.HasValue) return;
+        seat.SetSelectionSilently(StudentSeatOption.Empty);
+        SaveSeatAssignments();
+    }
+
+    private void SaveSeatAssignments()
+    {
+        if (_currentPlan is null) return;
         _currentPlan.Assignments = Seats
             .Where(s => s.SelectedOption.StudentId.HasValue)
             .Select(s => new SeatAssignment
@@ -136,11 +190,13 @@ public partial class SeatingPlanTabViewModel : ObservableObject
         UpdateAssignmentSummary();
     }
 
-    private void UpdateAssignmentSummary()
+    public async Task AssessStudent(SeatCellViewModel seat)
     {
-        var assigned = Seats.Count(s => s.SelectedOption.StudentId.HasValue);
+        if (!seat.SelectedOption.StudentId.HasValue || OnAssessStudent is null) return;
-        var total = StudentOptions.Count - 1;
+        var assessment = new SeatAssessmentViewModel(_sessions, _participation, _aspects,
-        AssignmentSummary = $"{assigned} von {total} Schülern zugeordnet";
+            _groupId, seat.SelectedOption.StudentId.Value, seat.SelectedOption.DisplayName, IsEditable);
+        await OnAssessStudent(assessment);
+        OnAssessmentChanged?.Invoke();
     }
 
     [RelayCommand(CanExecute = nameof(CanEdit))]
@@ -203,11 +259,14 @@ public partial class SeatCellViewModel : ObservableObject
     private bool _suppressChange;
 
     [ObservableProperty] private StudentSeatOption _selectedOption;
+    [ObservableProperty] private bool _isDropTarget;
     public int Row { get; }
     public int Column { get; }
     public string PositionLabel => $"Reihe {Row + 1} · Platz {Column + 1}";
     public ObservableCollection<StudentSeatOption> Options { get; }
     public bool CanEdit { get; }
+    public bool IsOccupied => SelectedOption.StudentId.HasValue;
+    public string StudentName => IsOccupied ? SelectedOption.DisplayName : "Freier Platz";
 
     public SeatCellViewModel(int row, int column, ObservableCollection<StudentSeatOption> options,
         StudentSeatOption selectedOption, Action<SeatCellViewModel> onChanged, bool canEdit)
@@ -222,6 +281,8 @@ public partial class SeatCellViewModel : ObservableObject
 
     partial void OnSelectedOptionChanged(StudentSeatOption value)
     {
+        OnPropertyChanged(nameof(IsOccupied));
+        OnPropertyChanged(nameof(StudentName));
         if (!_suppressChange) _onChanged(this);
     }
 
@@ -233,6 +294,281 @@ public partial class SeatCellViewModel : ObservableObject
     }
 }
 
+public partial class SeatAssessmentViewModel : ObservableObject
+{
+    private readonly IParticipationRepository _entries;
+    private readonly ParticipationEntry? _entry;
+    private readonly bool _canEdit;
+
+    [ObservableProperty] private int _selectedAspectIndex;
+    [ObservableProperty] private string _attendanceLabel = "Noch nicht kontrolliert";
+    [ObservableProperty] private string _homeworkLabel = "Keine Hausaufgabe aufgegeben";
+
+    public string StudentName { get; }
+    public string SessionDisplay { get; }
+    public bool CanEdit => _canEdit && _entry is not null;
+    public string ReadOnlyHint => _entry is null
+        ? "Für heute existiert keine Sitzung. In einer archivierten Gruppe kann keine neue angelegt werden."
+        : "Archivierte Lerngruppe – Bewertung nur ansehen.";
+    public ObservableCollection<SeatAssessmentAspectRow> AspectRows { get; } = [];
+    public ObservableCollection<SeatAttendanceChoice> AttendanceChoices { get; } = [];
+    public ObservableCollection<SeatHomeworkChoice> HomeworkChoices { get; } = [];
+
+    public SeatAssessmentViewModel(IParticipationSessionRepository sessions,
+        IParticipationRepository entries, IParticipationAspectRepository aspects,
+        Guid groupId, Guid studentId, string studentName, bool canEdit)
+    {
+        _entries = entries;
+        _canEdit = canEdit;
+        StudentName = studentName;
+        var today = DateOnly.FromDateTime(DateTime.Today);
+        var session = sessions.GetByGroup(groupId).FirstOrDefault(s => s.Date == today);
+        if (session is null && canEdit)
+        {
+            session = new ParticipationSession
+            {
+                GroupId = groupId,
+                Date = today,
+                Comment = "Sitzplan",
+            };
+            sessions.Save(session);
+        }
+        SessionDisplay = session is null ? "Keine Sitzung für heute" : $"{session.Date:dd.MM.yyyy} · {session.Comment}";
+        _entry = session is null ? null
+            : entries.GetBySessionAndStudent(session.Id, studentId)
+              ?? new ParticipationEntry { SessionId = session.Id, StudentId = studentId };
+
+        var aspectDefinitions = aspects.GetDefaults().Concat(aspects.GetByGroup(groupId)).ToList();
+        if (aspectDefinitions.Count == 0) aspectDefinitions = DefaultParticipationAspects.All.Select(a => new ParticipationAspect
+        {
+            Key = a.Key, Label = a.Label, ValueType = a.ValueType, MaxPoints = a.MaxPoints,
+        }).ToList();
+        foreach (var (aspect, index) in aspectDefinitions.Select((a, i) => (a, i)))
+        {
+            var value = _entry?.Ratings.FirstOrDefault(r => r.Key == aspect.Key)?.Value;
+            AspectRows.Add(new SeatAssessmentAspectRow(index, aspect, value, ApplyRating));
+        }
+
+        BuildAttendanceChoices();
+        BuildHomeworkChoices();
+        RefreshStatusChoices();
+        SelectAspect(0);
+    }
+
+    private void BuildAttendanceChoices()
+    {
+        AttendanceChoices.Add(new("✓", "Anwesend", "Strg+1", AttendanceStatus.Present, SetAttendance));
+        AttendanceChoices.Add(new("?", "Entschuldigung offen", "Strg+2", AttendanceStatus.ExcusePending, SetAttendance));
+        AttendanceChoices.Add(new("⊘", "Entschuldigt", "Strg+5", AttendanceStatus.Excused, SetAttendance));
+        AttendanceChoices.Add(new("◇", "Schulveranstaltung", "Strg+7", AttendanceStatus.OtherSchoolEvent, SetAttendance));
+        AttendanceChoices.Add(new("✕", "Geschwänzt", "Strg+9", AttendanceStatus.Truant, SetAttendance));
+        AttendanceChoices.Add(new("!", "Unentschuldigt", "Strg+0", AttendanceStatus.Unexcused, SetAttendance));
+        AttendanceChoices.Add(new("·", "Nicht kontrolliert", "Strg+X", null, SetAttendance));
+    }
+
+    private void BuildHomeworkChoices()
+    {
+        HomeworkChoices.Add(new("✓", "Gemacht", "⌥1", HomeworkStatus.Completed, SetHomework));
+        HomeworkChoices.Add(new("◐", "Teilweise", "⌥3", HomeworkStatus.PartiallyCompleted, SetHomework));
+        HomeworkChoices.Add(new("◕", "Rest nachgereicht", "⌥4", HomeworkStatus.PartialSubmittedLate, SetHomework));
+        HomeworkChoices.Add(new("◒", "Rest fehlt", "⌥5", HomeworkStatus.PartialMissingOverdue, SetHomework));
+        HomeworkChoices.Add(new("!", "Nicht gemacht", "⌥7", HomeworkStatus.MissingOpen, SetHomework));
+        HomeworkChoices.Add(new("↺", "Nachgereicht", "⌥8", HomeworkStatus.SubmittedLate, SetHomework));
+        HomeworkChoices.Add(new("✕", "Nicht nachgereicht", "⌥0", HomeworkStatus.MissingOverdue, SetHomework));
+        HomeworkChoices.Add(new("·", "Keine aufgegeben", "⌥X", null, SetHomework));
+    }
+
+    public void SelectAspect(int index)
+    {
+        if (index < 0 || index >= AspectRows.Count) return;
+        SelectedAspectIndex = index;
+        foreach (var row in AspectRows) row.IsActive = row.Index == index;
+    }
+
+    public void MoveAspect(int delta)
+    {
+        if (AspectRows.Count == 0) return;
+        SelectAspect(Math.Clamp(SelectedAspectIndex + delta, 0, AspectRows.Count - 1));
+    }
+
+    public void SetRatingByNumber(int number)
+    {
+        if (!CanEdit) return;
+        var row = AspectRows.ElementAtOrDefault(SelectedAspectIndex);
+        if (row is null) return;
+        if (row.ValueType == AspectValueType.Points)
+            row.ApplyValue(Math.Clamp(number, 0, row.MaxPoints));
+        else
+        {
+            var steps = ParticipationRatingScale.Steps(row.ValueType);
+            if (number >= 1 && number <= steps.Count) row.ApplyValue(steps[number - 1].Value);
+        }
+    }
+
+    public void AdjustCurrentRating(int delta)
+    {
+        if (!CanEdit) return;
+        var row = AspectRows.ElementAtOrDefault(SelectedAspectIndex);
+        row?.Adjust(delta);
+    }
+
+    public void ClearCurrentRating()
+    {
+        if (!CanEdit) return;
+        AspectRows.ElementAtOrDefault(SelectedAspectIndex)?.ApplyValue(null);
+    }
+
+    public void ApplyAttendanceShortcut(int? digit, bool clear)
+    {
+        if (!CanEdit) return;
+        var status = clear ? null : digit switch
+        {
+            1 => AttendanceStatus.Present, 2 => AttendanceStatus.ExcusePending,
+            5 => AttendanceStatus.Excused, 7 => AttendanceStatus.OtherSchoolEvent,
+            9 => AttendanceStatus.Truant, 0 => AttendanceStatus.Unexcused,
+            _ => (AttendanceStatus?)null,
+        };
+        if (clear || digit is 0 or 1 or 2 or 5 or 7 or 9) SetAttendance(status);
+    }
+
+    public void ApplyHomeworkShortcut(int? digit, bool clear)
+    {
+        if (!CanEdit) return;
+        var status = clear ? null : digit switch
+        {
+            1 => HomeworkStatus.Completed, 3 => HomeworkStatus.PartiallyCompleted,
+            4 => HomeworkStatus.PartialSubmittedLate, 5 => HomeworkStatus.PartialMissingOverdue,
+            7 => HomeworkStatus.MissingOpen, 8 => HomeworkStatus.SubmittedLate,
+            0 => HomeworkStatus.MissingOverdue, _ => (HomeworkStatus?)null,
+        };
+        if (clear || digit is 0 or 1 or 3 or 4 or 5 or 7 or 8) SetHomework(status);
+    }
+
+    private void ApplyRating(string key, int? value)
+    {
+        if (!CanEdit || _entry is null) return;
+        var existing = _entry.Ratings.FirstOrDefault(r => r.Key == key);
+        if (value is null)
+        {
+            if (existing is not null) _entry.Ratings.Remove(existing);
+        }
+        else if (existing is null) _entry.Ratings.Add(new AspectRating { Key = key, Value = value.Value });
+        else existing.Value = value.Value;
+        _entries.Save(_entry);
+    }
+
+    private void SetAttendance(AttendanceStatus? status)
+    {
+        if (!CanEdit || _entry is null) return;
+        _entry.Attendance = status;
+        _entries.Save(_entry);
+        RefreshStatusChoices();
+    }
+
+    private void SetHomework(HomeworkStatus? status)
+    {
+        if (!CanEdit || _entry is null) return;
+        _entry.Homework = status;
+        _entry.HomeworkMissing = HomeworkDisplay.CountsAsMissing(status);
+        _entries.Save(_entry);
+        RefreshStatusChoices();
+    }
+
+    private void RefreshStatusChoices()
+    {
+        AttendanceLabel = AttendanceDisplay.Label(_entry?.Attendance);
+        HomeworkLabel = HomeworkDisplay.Label(_entry is null ? null : HomeworkDisplay.Effective(_entry));
+        foreach (var choice in AttendanceChoices) choice.IsSelected = choice.Status == _entry?.Attendance;
+        var homework = _entry is null ? null : HomeworkDisplay.Effective(_entry);
+        foreach (var choice in HomeworkChoices) choice.IsSelected = choice.Status == homework;
+    }
+}
+
+public partial class SeatAssessmentAspectRow : ObservableObject
+{
+    private readonly Action<string, int?> _apply;
+    [ObservableProperty] private bool _isActive;
+    [ObservableProperty] private int? _value;
+    public int Index { get; }
+    public string Key { get; }
+    public string Label { get; }
+    public AspectValueType ValueType { get; }
+    public int MaxPoints { get; }
+    public string Shortcut => Index switch { 0 => "Q", 1 => "W", 2 => "E", 3 => "R", 4 => "T", _ => "" };
+    public string DisplayValue => ParticipationRatingScale.DisplayLabel(ValueType, Value);
+    public ObservableCollection<SeatRatingChoice> Choices { get; } = [];
+
+    public SeatAssessmentAspectRow(int index, ParticipationAspect aspect, int? value,
+        Action<string, int?> apply)
+    {
+        Index = index; Key = aspect.Key; Label = aspect.Label; ValueType = aspect.ValueType;
+        MaxPoints = aspect.MaxPoints; _value = value; _apply = apply;
+        var steps = ValueType == AspectValueType.Points
+            ? Enumerable.Range(0, Math.Min(MaxPoints, 9) + 1).Select(v => (v, v.ToString())).ToList()
+            : ParticipationRatingScale.Steps(ValueType).ToList();
+        foreach (var (step, i) in steps.Select((s, i) => (s, i)))
+            Choices.Add(new SeatRatingChoice(step.Item2, ValueType == AspectValueType.Points ? step.Item1.ToString() : (i + 1).ToString(),
+                step.Item1, step.Item1 == value, ApplyValue));
+    }
+
+    public void ApplyValue(int? value)
+    {
+        Value = value;
+        OnPropertyChanged(nameof(DisplayValue));
+        foreach (var choice in Choices) choice.IsSelected = choice.Value == value;
+        _apply(Key, value);
+    }
+
+    public void Adjust(int delta)
+    {
+        if (ValueType == AspectValueType.Points)
+        {
+            ApplyValue(Math.Clamp((Value ?? (delta > 0 ? -1 : MaxPoints + 1)) + delta, 0, MaxPoints));
+            return;
+        }
+        var steps = ParticipationRatingScale.Steps(ValueType).Select(s => s.Value).ToList();
+        if (steps.Count == 0) return;
+        var index = Value.HasValue ? steps.IndexOf(Value.Value) : (delta > 0 ? -1 : steps.Count);
+        ApplyValue(steps[Math.Clamp(index + delta, 0, steps.Count - 1)]);
+    }
+
+    [RelayCommand] private void Clear() => ApplyValue(null);
+    [RelayCommand] private void Increment() => Adjust(1);
+    [RelayCommand] private void Decrement() => Adjust(-1);
+}
+
+public partial class SeatRatingChoice(string label, string shortcut, int value, bool isSelected,
+    Action<int?> apply) : ObservableObject
+{
+    public string Label { get; } = label;
+    public string Shortcut { get; } = shortcut;
+    public int Value { get; } = value;
+    [ObservableProperty] private bool _isSelected = isSelected;
+    [RelayCommand] private void Apply() => apply(Value);
+}
+
+public partial class SeatAttendanceChoice(string symbol, string label, string shortcut,
+    AttendanceStatus? status, Action<AttendanceStatus?> apply) : ObservableObject
+{
+    public string Symbol { get; } = symbol;
+    public string Label { get; } = label;
+    public string Shortcut { get; } = shortcut;
+    public AttendanceStatus? Status { get; } = status;
+    [ObservableProperty] private bool _isSelected;
+    [RelayCommand] private void Apply() => apply(Status);
+}
+
+public partial class SeatHomeworkChoice(string symbol, string label, string shortcut,
+    HomeworkStatus? status, Action<HomeworkStatus?> apply) : ObservableObject
+{
+    public string Symbol { get; } = symbol;
+    public string Label { get; } = label;
+    public string Shortcut { get; } = shortcut;
+    public HomeworkStatus? Status { get; } = status;
+    [ObservableProperty] private bool _isSelected;
+    [RelayCommand] private void Apply() => apply(Status);
+}
+
 public partial class SeatingPlanDialogViewModel : ObservableObject
 {
     private readonly ISeatingPlanRepository _plans;
@@ -256,8 +592,8 @@ public partial class SeatingPlanDialogViewModel : ObservableObject
         _groupId = groupId;
         _editingPlan = editingPlan;
         if (editingPlan is null) return;
-        Name = editingPlan.Name;
+        Name = editingPlan.Name ?? "";
-        Room = editingPlan.Room;
+        Room = editingPlan.Room ?? "";
         Rows = editingPlan.Rows;
         Columns = editingPlan.Columns;
     }
@@ -281,8 +617,8 @@ public partial class SeatingPlanDialogViewModel : ObservableObject
         if (!valid) return;
 
         var plan = _editingPlan ?? new SeatingPlan { GroupId = _groupId };
-        plan.Name = Name.Trim();
+        plan.Name = Name?.Trim() ?? "";
-        plan.Room = Room.Trim();
+        plan.Room = Room?.Trim() ?? "";
         plan.Rows = decimal.ToInt32(Rows);
         plan.Columns = decimal.ToInt32(Columns);
         try

LehrerApp.Desktop/Views/Groups/SeatAssessmentDialog.axaml

@@ -0,0 +1,133 @@
+<Window xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:vm="clr-namespace:LehrerApp.Desktop.ViewModels.Groups"
+        x:Class="LehrerApp.Desktop.Views.Groups.SeatAssessmentDialog"
+        x:DataType="vm:SeatAssessmentViewModel"
+        Title="Sitzplatz-Schnelleingabe" Width="660" Height="700"
+        MinWidth="560" MinHeight="560" CanResize="True"
+        WindowStartupLocation="CenterOwner">
+  <Window.Styles>
+    <Style Selector="Button.choice">
+      <Setter Property="Background" Value="Transparent"/>
+      <Setter Property="BorderBrush" Value="{DynamicResource SystemControlForegroundBaseLowBrush}"/>
+      <Setter Property="BorderThickness" Value="1"/>
+      <Setter Property="Padding" Value="8,5"/>
+    </Style>
+    <Style Selector="Button.choice.selected">
+      <Setter Property="Background" Value="{DynamicResource SystemAccentColorLight2}"/>
+      <Setter Property="BorderBrush" Value="{DynamicResource SystemAccentColor}"/>
+      <Setter Property="BorderThickness" Value="2"/>
+    </Style>
+    <Style Selector="Border.aspectrow">
+      <Setter Property="BorderBrush" Value="Transparent"/>
+      <Setter Property="BorderThickness" Value="1"/>
+      <Setter Property="Background" Value="Transparent"/>
+    </Style>
+    <Style Selector="Border.aspectrow.active">
+      <Setter Property="BorderBrush" Value="{DynamicResource SystemAccentColor}"/>
+      <Setter Property="Background" Value="{DynamicResource SystemAccentColorLight3}"/>
+    </Style>
+  </Window.Styles>
+
+  <Grid RowDefinitions="Auto,*,Auto" Margin="20">
+    <Grid Grid.Row="0" ColumnDefinitions="*,Auto" Margin="0,0,0,14">
+      <StackPanel>
+        <TextBlock Text="{Binding StudentName}" FontSize="22" FontWeight="SemiBold"/>
+        <TextBlock Text="{Binding SessionDisplay}" FontSize="12" Opacity="0.55"/>
+      </StackPanel>
+      <Button Grid.Column="1" Content="Schließen" Click="OnClose" VerticalAlignment="Center"/>
+    </Grid>
+
+    <ScrollViewer Grid.Row="1">
+      <StackPanel Spacing="16" IsEnabled="{Binding CanEdit}">
+        <Border Background="#FFF3CD" CornerRadius="6" Padding="10"
+                IsVisible="{Binding CanEdit, Converter={x:Static BoolConverters.Not}}">
+          <TextBlock Text="{Binding ReadOnlyHint}" Foreground="#92400E" TextWrapping="Wrap"/>
+        </Border>
+
+        <StackPanel Spacing="7">
+          <TextBlock Text="MITARBEIT" FontSize="11" FontWeight="Bold" Opacity="0.5"/>
+          <ItemsControl ItemsSource="{Binding AspectRows}">
+            <ItemsControl.ItemTemplate>
+              <DataTemplate x:DataType="vm:SeatAssessmentAspectRow">
+                <Border Classes="aspectrow" Classes.active="{Binding IsActive}"
+                        CornerRadius="7" Padding="9" Margin="0,3">
+                  <Grid ColumnDefinitions="150,*">
+                    <StackPanel VerticalAlignment="Center">
+                      <TextBlock FontWeight="SemiBold">
+                        <Run Text="["/><Run Text="{Binding Shortcut}"/><Run Text="]  "/><Run Text="{Binding Label}"/>
+                      </TextBlock>
+                      <TextBlock Text="{Binding DisplayValue}" FontSize="11" Opacity="0.6"/>
+                    </StackPanel>
+                    <WrapPanel Grid.Column="1" HorizontalAlignment="Right">
+                      <ItemsControl ItemsSource="{Binding Choices}">
+                        <ItemsControl.ItemsPanel><ItemsPanelTemplate><StackPanel Orientation="Horizontal"/></ItemsPanelTemplate></ItemsControl.ItemsPanel>
+                        <ItemsControl.ItemTemplate>
+                          <DataTemplate x:DataType="vm:SeatRatingChoice">
+                            <Button Classes="choice" Classes.selected="{Binding IsSelected}"
+                                    Command="{Binding ApplyCommand}" Margin="2">
+                              <StackPanel>
+                                <TextBlock Text="{Binding Label}" HorizontalAlignment="Center" FontWeight="SemiBold"/>
+                                <TextBlock Text="{Binding Shortcut}" HorizontalAlignment="Center" FontSize="9" Opacity="0.5"/>
+                              </StackPanel>
+                            </Button>
+                          </DataTemplate>
+                        </ItemsControl.ItemTemplate>
+                      </ItemsControl>
+                      <Button Classes="choice" Content="−" Command="{Binding DecrementCommand}" Margin="2"/>
+                      <Button Classes="choice" Content="+" Command="{Binding IncrementCommand}" Margin="2"/>
+                      <Button Classes="choice" Content="Löschen" Command="{Binding ClearCommand}" Margin="2"/>
+                    </WrapPanel>
+                  </Grid>
+                </Border>
+              </DataTemplate>
+            </ItemsControl.ItemTemplate>
+          </ItemsControl>
+        </StackPanel>
+
+        <StackPanel Spacing="7">
+          <TextBlock Text="ANWESENHEIT" FontSize="11" FontWeight="Bold" Opacity="0.5"/>
+          <TextBlock Text="{Binding AttendanceLabel}" FontSize="12"/>
+          <ItemsControl ItemsSource="{Binding AttendanceChoices}">
+            <ItemsControl.ItemsPanel><ItemsPanelTemplate><WrapPanel/></ItemsPanelTemplate></ItemsControl.ItemsPanel>
+            <ItemsControl.ItemTemplate>
+              <DataTemplate x:DataType="vm:SeatAttendanceChoice">
+                <Button Classes="choice" Classes.selected="{Binding IsSelected}"
+                        Command="{Binding ApplyCommand}" Margin="2">
+                  <StackPanel Orientation="Horizontal" Spacing="5">
+                    <TextBlock Text="{Binding Symbol}" FontWeight="Bold"/>
+                    <TextBlock Text="{Binding Label}"/>
+                    <TextBlock Text="{Binding Shortcut}" FontSize="9" Opacity="0.5" VerticalAlignment="Center"/>
+                  </StackPanel>
+                </Button>
+              </DataTemplate>
+            </ItemsControl.ItemTemplate>
+          </ItemsControl>
+        </StackPanel>
+
+        <StackPanel Spacing="7">
+          <TextBlock Text="HAUSAUFGABEN" FontSize="11" FontWeight="Bold" Opacity="0.5"/>
+          <TextBlock Text="{Binding HomeworkLabel}" FontSize="12"/>
+          <ItemsControl ItemsSource="{Binding HomeworkChoices}">
+            <ItemsControl.ItemsPanel><ItemsPanelTemplate><WrapPanel/></ItemsPanelTemplate></ItemsControl.ItemsPanel>
+            <ItemsControl.ItemTemplate>
+              <DataTemplate x:DataType="vm:SeatHomeworkChoice">
+                <Button Classes="choice" Classes.selected="{Binding IsSelected}"
+                        Command="{Binding ApplyCommand}" Margin="2">
+                  <StackPanel Orientation="Horizontal" Spacing="5">
+                    <TextBlock Text="{Binding Symbol}" FontWeight="Bold"/>
+                    <TextBlock Text="{Binding Label}"/>
+                    <TextBlock Text="{Binding Shortcut}" FontSize="9" Opacity="0.5" VerticalAlignment="Center"/>
+                  </StackPanel>
+                </Button>
+              </DataTemplate>
+            </ItemsControl.ItemTemplate>
+          </ItemsControl>
+        </StackPanel>
+      </StackPanel>
+    </ScrollViewer>
+
+    <TextBlock Grid.Row="2" Margin="0,12,0,0" FontSize="10" Opacity="0.55" TextWrapping="Wrap"
+               Text="Mitarbeit: Q/W/E/R/T Aspekt · 1–5 Bewertung · +/− anpassen · Backspace löschen · ←/→ Aspekt  |  Anwesenheit: Strg+1/2/5/7/9/0, Strg+X  |  Hausaufgaben: ⌥+1/3/4/5/7/8/0, ⌥+X  |  Esc schließen"/>
+  </Grid>
+</Window>

LehrerApp.Desktop/Views/Groups/SeatAssessmentDialog.axaml.cs

@@ -0,0 +1,80 @@
+using Avalonia.Controls;
+using Avalonia.Input;
+using Avalonia.Interactivity;
+using LehrerApp.Desktop.ViewModels.Groups;
+
+namespace LehrerApp.Desktop.Views.Groups;
+
+public partial class SeatAssessmentDialog : Window
+{
+    public SeatAssessmentDialog()
+    {
+        InitializeComponent();
+        AddHandler(KeyDownEvent, OnPreviewKeyDown, RoutingStrategies.Tunnel, handledEventsToo: true);
+    }
+
+    protected override void OnOpened(EventArgs e)
+    {
+        base.OnOpened(e);
+        Focus();
+    }
+
+    private void OnPreviewKeyDown(object? sender, KeyEventArgs e)
+    {
+        if (DataContext is not SeatAssessmentViewModel vm) return;
+        var digit = DigitFromEvent(e);
+        var clear = e.Key == Key.X || e.PhysicalKey == PhysicalKey.X;
+        if (e.KeyModifiers.HasFlag(KeyModifiers.Control))
+        {
+            if (clear || digit is not null) vm.ApplyAttendanceShortcut(digit, clear);
+            e.Handled = clear || digit is not null;
+            return;
+        }
+        if (e.KeyModifiers.HasFlag(KeyModifiers.Alt))
+        {
+            if (clear || digit is not null) vm.ApplyHomeworkShortcut(digit, clear);
+            e.Handled = clear || digit is not null;
+            return;
+        }
+        if (digit is not null)
+        {
+            vm.SetRatingByNumber(digit.Value);
+            e.Handled = true;
+            return;
+        }
+
+        switch (e.Key)
+        {
+            case Key.Q: vm.SelectAspect(0); e.Handled = true; break;
+            case Key.W: vm.SelectAspect(1); e.Handled = true; break;
+            case Key.E: vm.SelectAspect(2); e.Handled = true; break;
+            case Key.R: vm.SelectAspect(3); e.Handled = true; break;
+            case Key.T: vm.SelectAspect(4); e.Handled = true; break;
+            case Key.Left: vm.MoveAspect(-1); e.Handled = true; break;
+            case Key.Right: vm.MoveAspect(1); e.Handled = true; break;
+            case Key.OemPlus or Key.Add: vm.AdjustCurrentRating(1); e.Handled = true; break;
+            case Key.OemMinus or Key.Subtract: vm.AdjustCurrentRating(-1); e.Handled = true; break;
+            case Key.Back: vm.ClearCurrentRating(); e.Handled = true; break;
+            case Key.Escape: Close(); e.Handled = true; break;
+        }
+    }
+
+    private static int? DigitFromEvent(KeyEventArgs e) => e.PhysicalKey switch
+    {
+        PhysicalKey.Digit0 => 0, PhysicalKey.Digit1 => 1, PhysicalKey.Digit2 => 2,
+        PhysicalKey.Digit3 => 3, PhysicalKey.Digit4 => 4, PhysicalKey.Digit5 => 5,
+        PhysicalKey.Digit6 => 6, PhysicalKey.Digit7 => 7, PhysicalKey.Digit8 => 8,
+        PhysicalKey.Digit9 => 9,
+        _ => e.Key switch
+        {
+            Key.D0 or Key.NumPad0 => 0, Key.D1 or Key.NumPad1 => 1,
+            Key.D2 or Key.NumPad2 => 2, Key.D3 or Key.NumPad3 => 3,
+            Key.D4 or Key.NumPad4 => 4, Key.D5 or Key.NumPad5 => 5,
+            Key.D6 or Key.NumPad6 => 6, Key.D7 or Key.NumPad7 => 7,
+            Key.D8 or Key.NumPad8 => 8, Key.D9 or Key.NumPad9 => 9,
+            _ => null,
+        },
+    };
+
+    private void OnClose(object? sender, RoutedEventArgs e) => Close();
+}

LehrerApp.Desktop/Views/Groups/SeatingPlanTabView.axaml

@@ -3,6 +3,21 @@
              xmlns:vm="clr-namespace:LehrerApp.Desktop.ViewModels.Groups"
              x:Class="LehrerApp.Desktop.Views.Groups.SeatingPlanTabView"
              x:DataType="vm:SeatingPlanTabViewModel">
+  <UserControl.Styles>
+    <Style Selector="Border.seat">
+      <Setter Property="Background" Value="{DynamicResource SystemControlBackgroundAltHighBrush}"/>
+      <Setter Property="BorderBrush" Value="{DynamicResource SystemControlForegroundBaseLowBrush}"/>
+      <Setter Property="BorderThickness" Value="1"/>
+    </Style>
+    <Style Selector="Border.seat.occupied">
+      <Setter Property="BorderBrush" Value="{DynamicResource SystemAccentColor}"/>
+    </Style>
+    <Style Selector="Border.seat.droptarget">
+      <Setter Property="Background" Value="{DynamicResource SystemAccentColorLight2}"/>
+      <Setter Property="BorderBrush" Value="{DynamicResource SystemAccentColor}"/>
+      <Setter Property="BorderThickness" Value="2"/>
+    </Style>
+  </UserControl.Styles>
   <Grid ColumnDefinitions="260,*">
     <Border Grid.Column="0" BorderBrush="{DynamicResource SystemControlForegroundBaseLowBrush}"
             BorderThickness="0,0,1,0" Padding="16">
@@ -51,8 +66,11 @@
             <TextBlock Text="{Binding PlanTitle}" FontSize="22" FontWeight="SemiBold"/>
             <TextBlock Text="{Binding PlanSubtitle}" Opacity="0.65"/>
           </StackPanel>
-          <TextBlock Grid.Column="1" Text="{Binding AssignmentSummary}" VerticalAlignment="Bottom"
+          <StackPanel Grid.Column="1" VerticalAlignment="Bottom">
-                     FontSize="12" Opacity="0.6"/>
+            <TextBlock Text="{Binding AssignmentSummary}" HorizontalAlignment="Right" FontSize="12" Opacity="0.6"/>
+            <TextBlock Text="Ziehen: Platz ändern · Klicken: bewerten" HorizontalAlignment="Right"
+                       FontSize="11" Opacity="0.5"/>
+          </StackPanel>
         </Grid>
 
         <ScrollViewer Grid.Row="1" HorizontalScrollBarVisibility="Auto"
@@ -70,24 +88,60 @@
               </ItemsControl.ItemsPanel>
               <ItemsControl.ItemTemplate>
                 <DataTemplate x:DataType="vm:SeatCellViewModel">
-                  <Border Width="190" MinHeight="76" Margin="5" Padding="10"
+                  <Border Classes="seat" Classes.occupied="{Binding IsOccupied}"
-                          BorderBrush="{DynamicResource SystemControlForegroundBaseLowBrush}"
+                          Classes.droptarget="{Binding IsDropTarget}"
-                          BorderThickness="1" CornerRadius="7">
+                          Width="190" MinHeight="76" Margin="5" Padding="10"
+                          CornerRadius="7"
+                          DragDrop.AllowDrop="True"
+                          DragDrop.DragEnter="OnSeatDragEnter"
+                          DragDrop.DragLeave="OnSeatDragLeave"
+                          DragDrop.DragOver="OnSeatDragOver"
+                          DragDrop.Drop="OnSeatDrop"
+                          PointerPressed="OnDragSourcePressed"
+                          PointerMoved="OnDragSourceMoved"
+                          PointerReleased="OnDragSourceReleased"
+                          Tapped="OnSeatTapped">
                     <StackPanel Spacing="5">
-                      <TextBlock Text="{Binding PositionLabel}" FontSize="10" Opacity="0.5"/>
+                      <Grid ColumnDefinitions="*,Auto">
-                      <ComboBox ItemsSource="{Binding Options}" SelectedItem="{Binding SelectedOption}"
+                        <TextBlock Text="{Binding PositionLabel}" FontSize="10" Opacity="0.5"/>
-                                IsEnabled="{Binding CanEdit}" HorizontalAlignment="Stretch">
+                        <TextBlock Grid.Column="1" Text="⠿" Opacity="0.45" IsVisible="{Binding IsOccupied}"/>
-                        <ComboBox.ItemTemplate>
+                      </Grid>
-                          <DataTemplate x:DataType="vm:StudentSeatOption">
+                      <TextBlock Text="{Binding StudentName}" FontWeight="SemiBold" FontSize="13"
-                            <TextBlock Text="{Binding DisplayName}"/>
+                                 HorizontalAlignment="Center" VerticalAlignment="Center"/>
-                          </DataTemplate>
-                        </ComboBox.ItemTemplate>
-                      </ComboBox>
                     </StackPanel>
                   </Border>
                 </DataTemplate>
               </ItemsControl.ItemTemplate>
             </ItemsControl>
+
+            <Border DragDrop.AllowDrop="True" DragDrop.DragOver="OnUnassignedDragOver"
+                    DragDrop.Drop="OnUnassignedDrop"
+                    BorderBrush="{DynamicResource SystemControlForegroundBaseLowBrush}"
+                    BorderThickness="1" CornerRadius="7" Padding="12" Margin="5,8">
+              <StackPanel Spacing="8">
+                <TextBlock Text="NICHT ZUGEORDNET" FontSize="10" FontWeight="Bold" Opacity="0.5"/>
+                <TextBlock Text="Schüler hierher ziehen, um einen Platz zu leeren."
+                           FontSize="11" Opacity="0.5"/>
+                <ItemsControl ItemsSource="{Binding UnassignedStudents}">
+                  <ItemsControl.ItemsPanel>
+                    <ItemsPanelTemplate><WrapPanel/></ItemsPanelTemplate>
+                  </ItemsControl.ItemsPanel>
+                  <ItemsControl.ItemTemplate>
+                    <DataTemplate x:DataType="vm:StudentSeatOption">
+                      <Border Background="{DynamicResource SystemAccentColorLight2}" CornerRadius="5"
+                              Padding="9,5" Margin="0,0,6,6"
+                              PointerPressed="OnDragSourcePressed"
+                              PointerMoved="OnDragSourceMoved"
+                              PointerReleased="OnDragSourceReleased">
+                        <TextBlock Text="{Binding DisplayName}" FontSize="12"/>
+                      </Border>
+                    </DataTemplate>
+                  </ItemsControl.ItemTemplate>
+                </ItemsControl>
+                <TextBlock Text="Alle Schüler sind zugeordnet." Classes="emptyhint"
+                           IsVisible="{Binding !UnassignedStudents.Count}"/>
+              </StackPanel>
+            </Border>
           </StackPanel>
         </ScrollViewer>
       </Grid>

LehrerApp.Desktop/Views/Groups/SeatingPlanTabView.axaml.cs

@@ -1,4 +1,7 @@
 using Avalonia.Controls;
+using Avalonia.Input;
+using Avalonia.Interactivity;
+using Avalonia.Threading;
 using LehrerApp.Core.Models;
 using LehrerApp.Desktop.ViewModels.Groups;
 using LehrerApp.Desktop.Views.Shared;
@@ -7,6 +10,15 @@ namespace LehrerApp.Desktop.Views.Groups;
 
 public partial class SeatingPlanTabView : UserControl
 {
+    private object? _dragCandidate;
+    private PointerPressedEventArgs? _dragTrigger;
+    private Avalonia.Point _pressPosition;
+    private SeatCellViewModel? _draggedSeat;
+    private StudentSeatOption? _draggedStudent;
+    private SeatCellViewModel? _pendingDropTarget;
+    private bool _pendingClearSeat;
+    private DateTime _ignoreTapUntil;
+
     public SeatingPlanTabView() => InitializeComponent();
 
     protected override void OnDataContextChanged(EventArgs e)
@@ -16,9 +28,128 @@ public partial class SeatingPlanTabView : UserControl
         {
             vm.OnEditPlan = ShowPlanDialog;
             vm.OnConfirmDelete = ShowDeleteConfirmDialog;
+            vm.OnAssessStudent = ShowAssessmentDialog;
         }
     }
 
+    private void OnDragSourcePressed(object? sender, PointerPressedEventArgs e)
+    {
+        if (sender is not Control control ||
+            !e.GetCurrentPoint(control).Properties.IsLeftButtonPressed) return;
+        var candidate = control.DataContext;
+        if (candidate is SeatCellViewModel { IsOccupied: false } or null) return;
+        if (DataContext is not SeatingPlanTabViewModel { IsEditable: true }) return;
+        _dragCandidate = candidate;
+        _dragTrigger = e;
+        _pressPosition = e.GetPosition(this);
+    }
+
+    private async void OnDragSourceMoved(object? sender, PointerEventArgs e)
+    {
+        if (_dragCandidate is null || _dragTrigger is null ||
+            !e.GetCurrentPoint(this).Properties.IsLeftButtonPressed) return;
+        var current = e.GetPosition(this);
+        if (Math.Abs(current.X - _pressPosition.X) < 6 && Math.Abs(current.Y - _pressPosition.Y) < 6) return;
+
+        _draggedSeat = _dragCandidate as SeatCellViewModel;
+        _draggedStudent = _dragCandidate as StudentSeatOption;
+        _pendingDropTarget = null;
+        _pendingClearSeat = false;
+        _dragCandidate = null;
+        var trigger = _dragTrigger;
+        _dragTrigger = null;
+        var data = new DataTransfer();
+        data.Add(DataTransferItem.CreateText("LehrerApp-Sitzplatz"));
+        var effect = await DragDrop.DoDragDropAsync(trigger, data, DragDropEffects.Move);
+        var draggedSeat = _draggedSeat;
+        var draggedStudent = _draggedStudent;
+        var dropTarget = _pendingDropTarget;
+        var clearSeat = _pendingClearSeat;
+        _draggedSeat = null;
+        _draggedStudent = null;
+        _pendingDropTarget = null;
+        _pendingClearSeat = false;
+        _ignoreTapUntil = DateTime.UtcNow.AddMilliseconds(250);
+
+        // Never mutate an ItemsControl while Avalonia is still processing its native
+        // drop event. Assigning an unassigned student removes the dragged source item.
+        if ((effect & DragDropEffects.Move) == 0 || DataContext is not SeatingPlanTabViewModel vm) return;
+        Dispatcher.UIThread.Post(() =>
+        {
+            if (clearSeat && draggedSeat is not null) vm.ClearSeat(draggedSeat);
+            else if (dropTarget is not null && draggedSeat is not null) vm.MoveSeat(draggedSeat, dropTarget);
+            else if (dropTarget is not null && draggedStudent is not null) vm.AssignStudent(draggedStudent, dropTarget);
+        }, DispatcherPriority.Background);
+    }
+
+    private void OnDragSourceReleased(object? sender, PointerReleasedEventArgs e)
+    {
+        _dragCandidate = null;
+        _dragTrigger = null;
+    }
+
+    private void OnSeatDragEnter(object? sender, DragEventArgs e)
+    {
+        if (sender is Border { DataContext: SeatCellViewModel target } && CanDropOn(target))
+            target.IsDropTarget = true;
+    }
+
+    private void OnSeatDragLeave(object? sender, DragEventArgs e)
+    {
+        if (sender is Border { DataContext: SeatCellViewModel target }) target.IsDropTarget = false;
+    }
+
+    private void OnSeatDragOver(object? sender, DragEventArgs e)
+    {
+        e.DragEffects = sender is Border { DataContext: SeatCellViewModel target } && CanDropOn(target)
+            ? DragDropEffects.Move : DragDropEffects.None;
+    }
+
+    private void OnSeatDrop(object? sender, DragEventArgs e)
+    {
+        if (sender is not Border { DataContext: SeatCellViewModel target }) return;
+        target.IsDropTarget = false;
+        if (!CanDropOn(target))
+        {
+            e.DragEffects = DragDropEffects.None;
+            return;
+        }
+        _pendingDropTarget = target;
+        _pendingClearSeat = false;
+        e.DragEffects = DragDropEffects.Move;
+    }
+
+    private bool CanDropOn(SeatCellViewModel target) =>
+        DataContext is SeatingPlanTabViewModel { IsEditable: true }
+        && ((_draggedSeat is not null && _draggedSeat != target) || _draggedStudent?.StudentId is not null);
+
+    private void OnUnassignedDragOver(object? sender, DragEventArgs e) =>
+        e.DragEffects = _draggedSeat is not null ? DragDropEffects.Move : DragDropEffects.None;
+
+    private void OnUnassignedDrop(object? sender, DragEventArgs e)
+    {
+        if (_draggedSeat is not null)
+        {
+            _pendingDropTarget = null;
+            _pendingClearSeat = true;
+            e.DragEffects = DragDropEffects.Move;
+        }
+    }
+
+    private async void OnSeatTapped(object? sender, TappedEventArgs e)
+    {
+        if (DateTime.UtcNow < _ignoreTapUntil || sender is not Border { DataContext: SeatCellViewModel seat }
+            || !seat.IsOccupied || DataContext is not SeatingPlanTabViewModel vm) return;
+        await vm.AssessStudent(seat);
+    }
+
+    private async Task ShowAssessmentDialog(SeatAssessmentViewModel vm)
+    {
+        var dialog = new SeatAssessmentDialog { DataContext = vm };
+        var owner = TopLevel.GetTopLevel(this) as Window;
+        if (owner is not null) await dialog.ShowDialog(owner);
+    }
+
     private async Task<SeatingPlan?> ShowPlanDialog(SeatingPlan? plan)
     {
         if (DataContext is not SeatingPlanTabViewModel vm) return null;

TODO.md

@@ -1151,10 +1151,14 @@ Hinweis in Kapitel 1 — betrifft auch Kurse, nicht nur Klassen.
       die bereits vorhandenen getrennten Adressfelder. DOCX-Vorlagen verwenden Word-
       Inhaltssteuerelemente mit dokumentierten Tags wie `Letter.Salutation`, `Contact.Address`,
       `Student.FirstName` und `Group.Name`.
-- [ ] **7.1.5** Sitzplan je Gruppe (Raster mit Drag & Drop), Sprung von Sitzplatz zur Bewertung.
+- [x] **7.1.5** Sitzplan je Gruppe (Raster mit Drag & Drop), Sprung von Sitzplatz zur Bewertung.
-  Grundfunktion umgesetzt: mehrere benannte Sitzpläne je Lerngruppe und Raum, konfigurierbares
+      Mehrere benannte Sitzpläne je Lerngruppe und Raum besitzen ein konfigurierbares Raster.
-  Raster sowie direkte Schülerzuordnung pro Platz. Offen bleiben Drag & Drop und der Sprung von
+      Schüler werden aus „Nicht zugeordnet“ auf Plätze gezogen, zwischen belegten Plätzen
-  einem Sitzplatz in die Mitarbeitsbewertung.
+      getauscht oder durch Ablegen im freien Bereich wieder entfernt. Ein Klick auf einen
+      belegten Sitz öffnet die kompakte Sitzplatz-Schnelleingabe für alle aktiven
+      Mitarbeitsaspekte, Anwesenheit und Hausaufgaben. Die Eingabe unterstützt Maus sowie
+      Tastenkürzel und schreibt in die heutige Mitarbeitssitzung; falls noch keine existiert,
+      wird einmalig eine Sitzung „Sitzplan“ für heute angelegt.
 
 ### 7.2 Gruppen
 - [x] **7.2.1** Gruppe bearbeiten und löschen — bereits vorhanden (`EditGroupCommand`/`DeleteGroupCommand`/