Allowed coins to be checked before sending API requests.

PcgsInvUi/App.axaml.cs

@@ -1,3 +1,5 @@
+using System;
+using System.Data.Entity.Migrations.Model;
 using Avalonia;
 using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Markup.Xaml;
@@ -15,15 +17,20 @@ public partial class App : Application {
 
     public override void OnFrameworkInitializationCompleted() {
         base.OnFrameworkInitializationCompleted();
-        
         if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop) {
             var coins = new CoinDatabase();
-
             desktop.MainWindow = new MainWindow {
                 DataContext = new MainWindowViewModel(coins),
             };
+            
+            desktop.Exit += (sender, args) => {
+                coins.UpdateCollection("CollectionTable");
+            };
         }
-
         base.OnFrameworkInitializationCompleted();
     }
+
+    public void OnExit(object sender, ControlledApplicationLifetimeExitEventArgs e) {
+        // Save the database?
+    }
 }