Add constant rich text placeholders

LehrerApp.Desktop/ViewModels/Settings/SettingsViewModel.LetterTemplates.cs

@@ -54,8 +54,8 @@ public partial class SettingsViewModel
     private LetterTemplateListItem CreateItem(InstalledTemplate template)
     {
         var loaded = _letterTemplates.Load(template);
-        return new(template, loaded.Manifest.SchemaVersion, loaded.Manifest.Placeholders.Count,
-            loaded.Manifest.Placeholders.Count(x => x.Required));
+        return new(template, loaded.Manifest.SchemaVersion, loaded.Manifest.Placeholders.Count(x => !x.IsConstant),
+            loaded.Manifest.Placeholders.Count(x => !x.IsConstant && x.Required));
     }
 }
 

LehrerApp.Desktop/ViewModels/Students/CreateLetterDialogViewModel.cs

@@ -77,7 +77,8 @@ public partial class CreateLetterDialogViewModel : ObservableObject
                 var loaded = _templates.Load(SelectedTemplate.Model); var values = BuildValues();
                 var validation = new TemplateLoader().Validate(loaded, values.ToDictionary(x => x.Key, x => x.Value.Type));
                 foreach (var issue in validation.Issues) Issues.Add(new(issue.Message, issue.Severity == ValidationSeverity.Error));
-                foreach (var required in loaded.Manifest.Placeholders.Where(x => x.Required && values.TryGetValue(x.Name, out var value) && IsEmpty(value)))
+                foreach (var required in loaded.Manifest.Placeholders.Where(x => !x.IsConstant && x.Required
+                             && values.TryGetValue(x.Name, out var value) && IsEmpty(value)))
                     Issues.Add(new($"Für das Pflichtfeld „{required.Name}“ ist kein Wert vorhanden.", true));
             }
             catch (Exception ex) when (ex is IOException or InvalidDataException or TemplateValidationException)