Fix Platzhalter Editer im TemplateDesigner

LehrerApp.TemplateDesigner/DesignerViewModel.cs

@@ -60,6 +60,8 @@ public partial class DesignerViewModel : ObservableObject
     public ObservableCollection<DesignerAsset> AssetItems { get; } = [];
     public ObservableCollection<StarterTemplateItem> StarterTemplates { get; } = [];
 
+    public DesignerViewModel() => SelectedPlaceholder = Placeholders.FirstOrDefault();
+
     public void Reset()
     {
         TemplateId = "neue-vorlage"; TemplateName = "Neue Vorlage"; Description = "";
@@ -83,7 +85,7 @@ public partial class DesignerViewModel : ObservableObject
         Id = TemplateId.Trim(), Name = TemplateName.Trim(), Description = Description.Trim(),
         PageSize = new((float)PageWidth, (float)PageHeight, Unit), LayoutFile = "layout.tpl",
         Metadata = BuildMetadata(),
-        Placeholders = Placeholders.Select(x => new PlaceholderDefinition(x.Name.Trim(), x.Type, x.Required)).ToList(),
+        Placeholders = BuildPlaceholders(),
     };
 
     public LoadedTemplate BuildLoaded()
@@ -106,6 +108,24 @@ public partial class DesignerViewModel : ObservableObject
     public ITemplateDataProvider BuildDataProvider() => new DesignerDataProvider(Placeholders.ToDictionary(
         x => x.Name.Trim(), x => x.ToValue(), StringComparer.Ordinal));
 
+    public DesignerPlaceholder AddPlaceholder()
+    {
+        var existing = Placeholders.Select(x => x.Name).ToHashSet(StringComparer.Ordinal);
+        var index = Placeholders.Count + 1;
+        while (existing.Contains($"Feld{index}")) index++;
+        var placeholder = new DesignerPlaceholder($"Feld{index}", PlaceholderType.Text, false, "Beispiel");
+        Placeholders.Add(placeholder); SelectedPlaceholder = placeholder; CanExport = false;
+        SetStatus($"Platzhalter „{placeholder.Name}“ angelegt. Details können jetzt bearbeitet werden.", false);
+        return placeholder;
+    }
+
+    public void RemoveSelectedPlaceholder()
+    {
+        if (SelectedPlaceholder is not { } selected) return;
+        Placeholders.Remove(selected); SelectedPlaceholder = null; CanExport = false;
+        SetStatus($"Platzhalter „{selected.Name}“ entfernt.", false);
+    }
+
     public void Load(LoadedTemplate template, string layoutSource)
     {
         TemplateId = template.Manifest.Id; TemplateName = template.Manifest.Name; Description = template.Manifest.Description;
@@ -118,6 +138,7 @@ public partial class DesignerViewModel : ObservableObject
         Placeholders.Clear();
         foreach (var placeholder in template.Manifest.Placeholders)
             Placeholders.Add(new(placeholder.Name, placeholder.Type, placeholder.Required, DesignerPlaceholder.SampleFor(placeholder.Type)));
+        SelectedPlaceholder = Placeholders.FirstOrDefault();
         Assets.Clear(); AssetItems.Clear();
         foreach (var asset in template.Assets) AddOrReplaceAsset(asset.Key, asset.Value, keepName: true);
         RefreshAssetUsage();
@@ -163,6 +184,20 @@ public partial class DesignerViewModel : ObservableObject
         return result;
     }
 
+    private List<PlaceholderDefinition> BuildPlaceholders()
+    {
+        var names = new HashSet<string>(StringComparer.Ordinal);
+        var result = new List<PlaceholderDefinition>(Placeholders.Count);
+        foreach (var placeholder in Placeholders)
+        {
+            var name = placeholder.Name.Trim();
+            if (name.Length == 0) throw new InvalidDataException("Ein Platzhaltername darf nicht leer sein.");
+            if (!names.Add(name)) throw new InvalidDataException($"Platzhalter „{name}“ ist mehrfach definiert.");
+            result.Add(new(name, placeholder.Type, placeholder.Required));
+        }
+        return result;
+    }
+
     private static ITemplateDataProvider BuildSampleDataProvider(TemplateManifest manifest) =>
         new DesignerDataProvider(manifest.Placeholders.ToDictionary(x => x.Name,
             x => new DesignerPlaceholder(x.Name, x.Type, x.Required, DesignerPlaceholder.SampleFor(x.Type)).ToValue(),

LehrerApp.TemplateDesigner/MainWindow.axaml

@@ -92,23 +92,34 @@
           </Grid>
 
           <Grid ColumnDefinitions="*,Auto"><TextBlock Text="Platzhalter &amp; Beispieldaten" Classes="section"/>
-            <Button Grid.Column="1" Content="＋" Click="OnAddPlaceholder"/></Grid>
+            <Button Grid.Column="1" Content="＋ Platzhalter" Click="OnAddPlaceholder"/></Grid>
           <DataGrid x:Name="PlaceholderGrid" ItemsSource="{Binding Placeholders}" SelectedItem="{Binding SelectedPlaceholder}"
-                    AutoGenerateColumns="False" Height="210" CanUserResizeColumns="True">
+                    AutoGenerateColumns="False" Height="180" CanUserResizeColumns="True" IsReadOnly="True">
             <DataGrid.Columns>
               <DataGridTextColumn Header="Name" Binding="{Binding Name}" Width="*"/>
-              <DataGridTextColumn Header="Typ" Binding="{Binding Type}" Width="105" IsReadOnly="True"/>
+              <DataGridTextColumn Header="Typ" Binding="{Binding Type}" Width="105"/>
               <DataGridCheckBoxColumn Header="Pflicht" Binding="{Binding Required}" Width="58"/>
               <DataGridTextColumn Header="Beispiel" Binding="{Binding Sample}" Width="*"/>
             </DataGrid.Columns>
           </DataGrid>
-          <Grid ColumnDefinitions="Auto,10,*">
-            <Button Content="Markierten Platzhalter entfernen" Click="OnRemovePlaceholder"/>
-            <StackPanel Grid.Column="2" Orientation="Horizontal" Spacing="8" VerticalAlignment="Center">
-              <TextBlock Text="Typ:" VerticalAlignment="Center"/>
-              <ComboBox Width="130" ItemsSource="{Binding PlaceholderTypes}" SelectedItem="{Binding SelectedPlaceholder.Type}"/>
+          <Border Padding="10" BorderBrush="#CBD5E1" BorderThickness="1" CornerRadius="4">
+            <StackPanel Spacing="8">
+              <TextBlock Text="Ausgewählten Platzhalter bearbeiten" FontWeight="SemiBold"/>
+              <Grid ColumnDefinitions="*,10,*">
+                <StackPanel><TextBlock Text="Name" Classes="label"/>
+                  <TextBox Text="{Binding SelectedPlaceholder.Name, Mode=TwoWay}" PlaceholderText="z. B. Empfaenger"/></StackPanel>
+                <StackPanel Grid.Column="2"><TextBlock Text="Datentyp" Classes="label"/>
+                  <ComboBox ItemsSource="{Binding PlaceholderTypes}"
+                            SelectedItem="{Binding SelectedPlaceholder.Type, Mode=TwoWay}"/></StackPanel>
+              </Grid>
+              <CheckBox Content="Pflichtwert" IsChecked="{Binding SelectedPlaceholder.Required, Mode=TwoWay}"/>
+              <StackPanel><TextBlock Text="Beispielwert für die Vorschau" Classes="label"/>
+                <TextBox Text="{Binding SelectedPlaceholder.Sample, Mode=TwoWay}" AcceptsReturn="True"
+                         MinHeight="58" TextWrapping="Wrap" PlaceholderText="Beispieldaten eingeben"/></StackPanel>
+              <Button Content="Ausgewählten Platzhalter entfernen" HorizontalAlignment="Left"
+                      Click="OnRemovePlaceholder"/>
             </StackPanel>
-          </Grid>
+          </Border>
 
           <Grid ColumnDefinitions="*,Auto"><TextBlock Text="Paket-Assets" Classes="section"/>
             <Button Grid.Column="1" Content="＋ Bild importieren …" Click="OnImportAsset"/></Grid>

LehrerApp.TemplateDesigner/MainWindow.axaml.cs

@@ -27,8 +27,7 @@ public partial class MainWindow : Window
         _viewModel.Reset(); _currentPackagePath = null; UpdateDocumentTitle();
     }
     private void OnExit(object? sender, RoutedEventArgs e) => Close();
-    private void OnAddPlaceholder(object? sender, RoutedEventArgs e) =>
-        _viewModel.Placeholders.Add(new($"Feld{_viewModel.Placeholders.Count + 1}", PlaceholderType.Text, false, "Beispiel"));
+    private void OnAddPlaceholder(object? sender, RoutedEventArgs e) => _viewModel.AddPlaceholder();
     private void OnAddMetadata(object? sender, RoutedEventArgs e)
     {
         var item = new DesignerMetadata($"custom-{_viewModel.MetadataItems.Count + 1}", "");
@@ -39,11 +38,7 @@ public partial class MainWindow : Window
         if (_viewModel.SelectedMetadata is not { } selected) return;
         _viewModel.MetadataItems.Remove(selected); _viewModel.SelectedMetadata = null; _viewModel.CanExport = false;
     }
-    private void OnRemovePlaceholder(object? sender, RoutedEventArgs e)
-    {
-        if (this.FindControl<DataGrid>("PlaceholderGrid")?.SelectedItem is DesignerPlaceholder selected)
-            _viewModel.Placeholders.Remove(selected);
-    }
+    private void OnRemovePlaceholder(object? sender, RoutedEventArgs e) => _viewModel.RemoveSelectedPlaceholder();
     private void OnAddElement(object? sender, RoutedEventArgs e)
     { try { _viewModel.AddElement(); } catch (Exception ex) { _viewModel.SetStatus(ex.Message, true); } }
     private void OnMeasureOverlayMode(object? sender, RoutedEventArgs e)