Mitarbeit bewerten begonnen, Schülerdaten, Gruppen

LehrerApp.Desktop/Views/Groups/GroupDetailView.axaml

@@ -1,6 +1,7 @@
 <UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              xmlns:vm="clr-namespace:LehrerApp.Desktop.ViewModels.Groups"
+             xmlns:views="clr-namespace:LehrerApp.Desktop.Views.Groups"
              x:Class="LehrerApp.Desktop.Views.Groups.GroupDetailView"
              x:DataType="vm:GroupDetailViewModel">
 
@@ -20,17 +21,14 @@
             <Run Text="{Binding StudentCount}"/>
             <Run Text=" Schüler"/>
           </TextBlock>
-          <Button Content="＋ Schüler" Command="{Binding AddStudentCommand}"/>
-          <Button Content="＋ Klausur" Command="{Binding AddExamCommand}"/>
+          <Button Content="＋ Schüler"   Command="{Binding AddStudentCommand}"/>
+          <Button Content="− Austragen"  Command="{Binding RemoveStudentCommand}"
+                  IsVisible="{Binding SelectedStudent, Converter={x:Static ObjectConverters.IsNotNull}}"/>
+          <Button Content="＋ Klausur"   Command="{Binding AddExamCommand}"/>
         </StackPanel>
       </Grid>
     </Border>
 
-    <!--
-      Avalonia 12: TabbedPage ersetzt manuelles Tab-System.
-      Kein ActiveTab-Property, kein IsVisible-Binding, keine eigenen Tab-Buttons.
-      TabPlacement="Top" → Tabs oben (wie Browser-Tabs).
-    -->
     <TabbedPage Grid.Row="1" TabPlacement="Top" SelectedIndex="{Binding ActiveTabIndex}">
 
       <!-- Tab: Übersicht -->
@@ -47,6 +45,7 @@
       <!-- Tab: Schüler -->
       <ContentPage Header="Schüler">
         <DataGrid ItemsSource="{Binding Students}"
+                  SelectedItem="{Binding SelectedStudent}"
                   AutoGenerateColumns="False"
                   IsReadOnly="True"
                   GridLinesVisibility="Horizontal"
@@ -61,6 +60,11 @@
         </DataGrid>
       </ContentPage>
 
+      <!-- Tab: Mitarbeit -->
+      <ContentPage Header="Mitarbeit">
+        <views:ParticipationTabView DataContext="{Binding ParticipationTab}"/>
+      </ContentPage>
+
       <!-- Tab: Klausuren -->
       <ContentPage Header="Klausuren">
         <DataGrid ItemsSource="{Binding Exams}"