Fehlerbehebung bei leerer DB;

MultipleChoiceTrainer/Controllers/HomeController.cs

@@ -30,7 +30,7 @@ namespace MultipleChoiceTrainer.Controllers
             if (signInManager.IsSignedIn(User))
             {
                 var categories = context.Categories.Include(e => e.Sections).ThenInclude(e => e.Questions).ToList();
-                var selectedCategory = categoryId.HasValue ? categoryId.Value : categories.First().Id;
+                var selectedCategory = categoryId ?? (categories.FirstOrDefault()?.Id);
                 return View(new HomeViewModel() { Categories = categories, SelectedCategoryId = selectedCategory });
             }
             return View();