refactor: route searching is starting only if departure/arrival city and date is specified

TicketOffice/Pages/Routes/Index.cshtml

@@ -40,7 +40,7 @@
         </div>
     </form>
     
-    @if (Model.Routes != null)
+    @if (Model.Routes != null && Model.Routes.Count > 0)
     {
         <div class="route-list">
             <table>
@@ -172,6 +172,12 @@
             </table>
         </div>
     }
+    else if (Model.Routes == null)
+    {
+        <div class="search-error">
+            <p>Введіть дату й місто відправлення або прибуття</p>
+        </div>
+    }
     else
     {
         <div class="search-error">

TicketOffice/Pages/Routes/Index.cshtml.cs

@@ -8,7 +8,7 @@ namespace TicketOffice.Pages.Routes;
 
 public class IndexModel : PageModel
 {
-    public List<Route> Routes { get; set; } = null!;
+    public List<Route> Routes { get; set; }
     [BindProperty(SupportsGet = true)] public string From { get; set; }
     [BindProperty(SupportsGet = true)] public string To { get; set; }
     [BindProperty(SupportsGet = true)] public DateTime Date { get; set; } = new DateTime(2022, 03, 28, 0, 0, 0).Date;
@@ -22,8 +22,11 @@ public class IndexModel : PageModel
     }
 
     public void OnGet()
+    {
+        if (!string.IsNullOrWhiteSpace(From) || !string.IsNullOrWhiteSpace(To))
         {
             RetrieveAllRoutes();
+        }
         
         if (!string.IsNullOrWhiteSpace(From))
         {
@@ -35,8 +38,11 @@ public class IndexModel : PageModel
             FilterRoutesByTo();
         }
 
+        if (!string.IsNullOrWhiteSpace(From) || !string.IsNullOrWhiteSpace(To))
+        {
             FilterRoutesByDate();
         }
+    }
 
     public void OnGetSortByNumber()
     {
@@ -119,6 +125,11 @@ public class IndexModel : PageModel
         });
     }
 
+    public void OnGetBuyTicket(int routeId)
+    {
+        
+    }
+    
     private void RetrieveAllRoutes()
     {
         Routes = _context.Route