fix: Briefe Kontaktauswahl

LehrerApp.Desktop/Views/Students/CreateLetterDialog.axaml

@@ -26,11 +26,17 @@
                      Classes="emptyhint" IsVisible="{Binding HasNoTemplates}"/>
         </StackPanel>
         <StackPanel Spacing="4">
-          <TextBlock Text="Kontakt *" FontSize="12" Opacity="0.7"/>
-          <ComboBox ItemsSource="{Binding Contacts}" SelectedItem="{Binding SelectedContact}"
-                    DisplayMemberBinding="{Binding Display}" HorizontalAlignment="Stretch"/>
-          <TextBlock Text="Kein aktueller Kontakt vorhanden." Classes="emptyhint"
-                     IsVisible="{Binding HasNoContacts}"/>
+          <TextBlock Text="Anschrift *" FontSize="12" Opacity="0.7"/>
+          <Border BorderBrush="{DynamicResource AppCardBorderBrush}" BorderThickness="1" CornerRadius="6" Padding="10">
+            <Grid ColumnDefinitions="*,Auto">
+              <TextBlock Grid.Column="0" Text="{Binding AddressPreview}" TextWrapping="Wrap"
+                         VerticalAlignment="Center" IsVisible="{Binding HasAddressPreview}"/>
+              <TextBlock Grid.Column="0" Text="Kein aktueller Kontakt vorhanden." Classes="emptyhint"
+                         VerticalAlignment="Center" IsVisible="{Binding HasNoContacts}"/>
+              <Button Grid.Column="1" Content="Kontakt wechseln …" Click="OnSelectContact"
+                      IsEnabled="{Binding !HasNoContacts}" VerticalAlignment="Center"/>
+            </Grid>
+          </Border>
         </StackPanel>
         <StackPanel Spacing="4">
           <TextBlock Text="Anrede *" FontSize="12" Opacity="0.7"/>

LehrerApp.Desktop/Views/Students/CreateLetterDialog.axaml.cs

@@ -30,6 +30,14 @@ public partial class CreateLetterDialog : Window
         if (DataContext is CreateLetterDialogViewModel vm) await ConfigureAttendanceCalendar(vm);
     }
 
+    private async void OnSelectContact(object? sender, RoutedEventArgs e)
+    {
+        if (DataContext is not CreateLetterDialogViewModel vm) return;
+        var dialogVm = new SelectContactDialogViewModel(vm.Contacts, vm.SelectedContact);
+        var dialog = new SelectContactDialog { DataContext = dialogVm };
+        if (await dialog.ShowDialog<bool>(this)) vm.SelectedContact = dialogVm.SelectedContact;
+    }
+
     private async Task<bool> ConfigureAttendanceCalendar(CreateLetterDialogViewModel vm)
     {
         var configVm = new AttendanceCalendarConfigurationViewModel(vm.GetAttendanceCalendarOptions());

LehrerApp.Desktop/Views/Students/SelectContactDialog.axaml

@@ -0,0 +1,33 @@
+<Window xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:vm="clr-namespace:LehrerApp.Desktop.ViewModels.Students"
+        x:Class="LehrerApp.Desktop.Views.Students.SelectContactDialog"
+        x:DataType="vm:SelectContactDialogViewModel"
+        Title="Kontakt wählen" Width="380" Height="440"
+        CanResize="False" WindowStartupLocation="CenterOwner">
+
+  <Grid RowDefinitions="Auto,*,Auto,Auto" Margin="24">
+
+    <TextBlock Grid.Row="0" Text="Kontakt für Anrede und Anschrift" Classes="dialogtitle" Margin="0,0,0,12"/>
+
+    <ListBox Grid.Row="1" ItemsSource="{Binding Contacts}" SelectedItem="{Binding SelectedContact}"
+             BorderThickness="1">
+      <ListBox.ItemTemplate>
+        <DataTemplate x:DataType="vm:LetterContactChoice">
+          <TextBlock Text="{Binding Display}" Padding="4,2"/>
+        </DataTemplate>
+      </ListBox.ItemTemplate>
+    </ListBox>
+
+    <Border Grid.Row="2" BorderBrush="{DynamicResource AppCardBorderBrush}" BorderThickness="1" CornerRadius="6"
+            Padding="10" Margin="0,12,0,0" IsVisible="{Binding HasAddressPreview}">
+      <TextBlock Text="{Binding AddressPreview}" TextWrapping="Wrap" FontSize="12"/>
+    </Border>
+
+    <Grid Grid.Row="3" ColumnDefinitions="*,10,*" Margin="0,16,0,0">
+      <Button Grid.Column="0" Content="Abbrechen" HorizontalAlignment="Stretch" Click="OnCancel"/>
+      <Button Grid.Column="2" Content="Übernehmen" HorizontalAlignment="Stretch" Click="OnApply"/>
+    </Grid>
+
+  </Grid>
+</Window>

LehrerApp.Desktop/Views/Students/SelectContactDialog.axaml.cs

@@ -0,0 +1,12 @@
+using Avalonia.Controls;
+using Avalonia.Interactivity;
+
+namespace LehrerApp.Desktop.Views.Students;
+
+public partial class SelectContactDialog : Window
+{
+    public SelectContactDialog() => InitializeComponent();
+
+    private void OnApply(object? sender, RoutedEventArgs e) => Close(true);
+    private void OnCancel(object? sender, RoutedEventArgs e) => Close(false);
+}