Anpassung am Sitzplan

LehrerApp.Desktop/Views/Groups/SeatingPlanTabView.axaml

@@ -60,8 +60,8 @@
                 HorizontalAlignment="Center"/>
       </StackPanel>
 
-      <Grid RowDefinitions="Auto,*" IsVisible="{Binding HasSelectedPlan}" Margin="24">
+      <Grid RowDefinitions="Auto,*" ColumnDefinitions="*,220" IsVisible="{Binding HasSelectedPlan}" Margin="24">
-        <Grid Grid.Row="0" ColumnDefinitions="*,Auto" Margin="0,0,0,18">
+        <Grid Grid.Row="0" Grid.ColumnSpan="2" ColumnDefinitions="*,Auto" Margin="0,0,0,18">
           <StackPanel Spacing="3">
             <TextBlock Text="{Binding PlanTitle}" FontSize="22" FontWeight="SemiBold"/>
             <TextBlock Text="{Binding PlanSubtitle}" Opacity="0.65"/>
@@ -73,8 +73,13 @@
           </StackPanel>
         </Grid>
 
-        <ScrollViewer Grid.Row="1" HorizontalScrollBarVisibility="Auto"
+        <ScrollViewer x:Name="RoomScrollViewer" Grid.Row="1" Grid.Column="0"
-                      VerticalScrollBarVisibility="Auto">
+                      Margin="0,0,16,0"
+                      HorizontalScrollBarVisibility="Auto"
+                      VerticalScrollBarVisibility="Auto"
+                      DragDrop.AllowDrop="True"
+                      DragDrop.DragOver="OnRoomDragOver"
+                      DragDrop.DragLeave="OnRoomDragLeave">
           <StackPanel Spacing="14" HorizontalAlignment="Center">
             <Border Background="{DynamicResource SystemControlBackgroundChromeMediumLowBrush}"
                     CornerRadius="6" Padding="36,8" HorizontalAlignment="Center">
@@ -113,38 +118,46 @@
                 </DataTemplate>
               </ItemsControl.ItemTemplate>
             </ItemsControl>
+          </StackPanel>
+        </ScrollViewer>
 
-            <Border DragDrop.AllowDrop="True" DragDrop.DragOver="OnUnassignedDragOver"
+        <!-- Die Schülerliste hat einen eigenen Scrollbereich und bleibt dadurch auch bei
+             großen Räumen neben den aktuell sichtbaren Sitzplätzen erreichbar. -->
+        <Border Grid.Row="1" Grid.Column="1"
+                DragDrop.AllowDrop="True" DragDrop.DragOver="OnUnassignedDragOver"
                 DragDrop.Drop="OnUnassignedDrop"
                 BorderBrush="{DynamicResource SystemControlForegroundBaseLowBrush}"
-                    BorderThickness="1" CornerRadius="7" Padding="12" Margin="5,8">
+                BorderThickness="1" CornerRadius="7" Padding="12">
-              <StackPanel Spacing="8">
+          <Grid RowDefinitions="Auto,Auto,*">
-                <TextBlock Text="NICHT ZUGEORDNET" FontSize="10" FontWeight="Bold" Opacity="0.5"/>
+            <TextBlock Grid.Row="0" Text="NICHT ZUGEORDNET" FontSize="10"
-                <TextBlock Text="Schüler hierher ziehen, um einen Platz zu leeren."
+                       FontWeight="Bold" Opacity="0.5"/>
-                           FontSize="11" Opacity="0.5"/>
+            <TextBlock Grid.Row="1" Margin="0,5,0,10"
+                       Text="Schüler auf einen Platz ziehen. Belegte Plätze hierher ziehen, um sie zu leeren."
+                       TextWrapping="Wrap" FontSize="11" Opacity="0.5"/>
+            <ScrollViewer Grid.Row="2" VerticalScrollBarVisibility="Auto"
+                          HorizontalScrollBarVisibility="Disabled">
+              <StackPanel Spacing="6">
                 <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"
+                              Padding="9,7"
                               PointerPressed="OnDragSourcePressed"
                               PointerMoved="OnDragSourceMoved"
                               PointerReleased="OnDragSourceReleased">
-                        <TextBlock Text="{Binding DisplayName}" FontSize="12"/>
+                        <TextBlock Text="{Binding DisplayName}" FontSize="12" TextTrimming="CharacterEllipsis"/>
                       </Border>
                     </DataTemplate>
                   </ItemsControl.ItemTemplate>
                 </ItemsControl>
                 <TextBlock Text="Alle Schüler sind zugeordnet." Classes="emptyhint"
+                           TextWrapping="Wrap"
                            IsVisible="{Binding !UnassignedStudents.Count}"/>
               </StackPanel>
-            </Border>
-          </StackPanel>
             </ScrollViewer>
           </Grid>
+        </Border>
+      </Grid>
     </Grid>
   </Grid>
 </UserControl>

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

@@ -10,6 +10,9 @@ namespace LehrerApp.Desktop.Views.Groups;
 
 public partial class SeatingPlanTabView : UserControl
 {
+    private const double AutoScrollEdgeSize = 72;
+    private const double AutoScrollStep = 14;
+
     private object? _dragCandidate;
     private PointerPressedEventArgs? _dragTrigger;
     private Avalonia.Point _pressPosition;
@@ -18,8 +21,15 @@ public partial class SeatingPlanTabView : UserControl
     private SeatCellViewModel? _pendingDropTarget;
     private bool _pendingClearSeat;
     private DateTime _ignoreTapUntil;
+    private readonly DispatcherTimer _autoScrollTimer;
+    private Avalonia.Vector _autoScrollDirection;
 
-    public SeatingPlanTabView() => InitializeComponent();
+    public SeatingPlanTabView()
+    {
+        InitializeComponent();
+        _autoScrollTimer = new DispatcherTimer { Interval = TimeSpan.FromMilliseconds(30) };
+        _autoScrollTimer.Tick += OnAutoScrollTick;
+    }
 
     protected override void OnDataContextChanged(EventArgs e)
     {
@@ -69,6 +79,7 @@ public partial class SeatingPlanTabView : UserControl
         _draggedStudent = null;
         _pendingDropTarget = null;
         _pendingClearSeat = false;
+        StopAutoScroll();
         _ignoreTapUntil = DateTime.UtcNow.AddMilliseconds(250);
 
         // Never mutate an ItemsControl while Avalonia is still processing its native
@@ -107,6 +118,7 @@ public partial class SeatingPlanTabView : UserControl
 
     private void OnSeatDrop(object? sender, DragEventArgs e)
     {
+        StopAutoScroll();
         if (sender is not Border { DataContext: SeatCellViewModel target }) return;
         target.IsDropTarget = false;
         if (!CanDropOn(target))
@@ -128,6 +140,7 @@ public partial class SeatingPlanTabView : UserControl
 
     private void OnUnassignedDrop(object? sender, DragEventArgs e)
     {
+        StopAutoScroll();
         if (_draggedSeat is not null)
         {
             _pendingDropTarget = null;
@@ -136,6 +149,50 @@ public partial class SeatingPlanTabView : UserControl
         }
     }
 
+    private void OnRoomDragOver(object? sender, DragEventArgs e)
+    {
+        if (_draggedSeat is null && _draggedStudent is null)
+        {
+            StopAutoScroll();
+            return;
+        }
+
+        var position = e.GetPosition(RoomScrollViewer);
+        _autoScrollDirection = new Avalonia.Vector(
+            GetAutoScrollDirection(position.X, RoomScrollViewer.Bounds.Width),
+            GetAutoScrollDirection(position.Y, RoomScrollViewer.Bounds.Height));
+
+        if (_autoScrollDirection == default)
+            StopAutoScroll();
+        else if (!_autoScrollTimer.IsEnabled)
+            _autoScrollTimer.Start();
+    }
+
+    private void OnRoomDragLeave(object? sender, DragEventArgs e) => StopAutoScroll();
+
+    private void OnAutoScrollTick(object? sender, EventArgs e)
+    {
+        var maxX = Math.Max(0, RoomScrollViewer.Extent.Width - RoomScrollViewer.Viewport.Width);
+        var maxY = Math.Max(0, RoomScrollViewer.Extent.Height - RoomScrollViewer.Viewport.Height);
+        var offset = RoomScrollViewer.Offset;
+        RoomScrollViewer.Offset = new Avalonia.Vector(
+            Math.Clamp(offset.X + _autoScrollDirection.X * AutoScrollStep, 0, maxX),
+            Math.Clamp(offset.Y + _autoScrollDirection.Y * AutoScrollStep, 0, maxY));
+    }
+
+    private static double GetAutoScrollDirection(double position, double viewportSize)
+    {
+        if (position < AutoScrollEdgeSize) return -1;
+        if (position > viewportSize - AutoScrollEdgeSize) return 1;
+        return 0;
+    }
+
+    private void StopAutoScroll()
+    {
+        _autoScrollDirection = default;
+        _autoScrollTimer.Stop();
+    }
+
     private async void OnSeatTapped(object? sender, TappedEventArgs e)
     {
         if (DateTime.UtcNow < _ignoreTapUntil || sender is not Border { DataContext: SeatCellViewModel seat }