Добавил обработку пустых запросов

PaydayFrontend/Models/UniversityDirectionsViewModel.cs

@@ -2,6 +2,18 @@
 
 public class UniversityDirectionsViewModel
 {
+    public UniversityDirectionsViewModel()
+    {
+    }
+
+    public UniversityDirectionsViewModel(University university, List<Direction> directions, string searchString)
+    {
+        University = university;
+        Directions = directions;
+        SearchString = searchString;
+    }
+
     public University University { get; set; }
     public List<Direction> Directions { get; set; }
+    public string SearchString { get; set; }
 }