Ensure ViewModel is only created once

Author: lukeblevins

Files/BaseLayout.cs

@@ -238,7 +238,7 @@ private void Page_Loaded(object sender, RoutedEventArgs e)
                 {
                     //App.CurrentInstance.ViewModel = new ItemViewModel();
                     //App.CurrentInstance.InteractionOperations = new Interaction();
-                    Page_Loaded(null, null);
+                    //Page_Loaded(null, null);
                 }
             }
         }

Files/Controls/Sidebar.xaml.cs

@@ -31,6 +31,7 @@ private void Sidebar_ItemInvoked(Microsoft.UI.Xaml.Controls.NavigationView sende
         {
             (App.CurrentInstance.OperationsControl as RibbonArea).RibbonViewModel.HomeItems.isEnabled = false;
             (App.CurrentInstance.OperationsControl as RibbonArea).RibbonViewModel.ShareItems.isEnabled = false;
+            if(args.InvokedItem == null) { return; }
 
             if ((args.InvokedItemContainer.DataContext as INavigationControlItem).ItemType == NavigationControlItemType.Location)
             {

Files/Navigation/UniversalPath.cs

@@ -17,7 +17,7 @@ public string path
 
             set
             {
-                if(value != null)
+                if(!string.IsNullOrWhiteSpace(value))
                 {
                     _path = value;
                     NotifyPropertyChanged("path");

Files/ProHome.xaml.cs

@@ -28,9 +28,9 @@ public sealed partial class ProHome : Page, IShellPage
     {
         Frame IShellPage.ContentFrame => ItemDisplayFrame;
 
-        Interaction IShellPage.InteractionOperations => new Interaction();
+        Interaction IShellPage.InteractionOperations => interactionOperation;
 
-        ItemViewModel IShellPage.ViewModel => new ItemViewModel();
+        ItemViewModel IShellPage.ViewModel => viewModel;
 
         BaseLayout IShellPage.ContentPage => GetContentOrNull();
 
@@ -146,6 +146,8 @@ protected override void OnNavigatedTo(NavigationEventArgs eventArgs)
             NavParams = eventArgs.Parameter.ToString();
         }
 
+        private ItemViewModel viewModel = null;
+        private Interaction interactionOperation = null;
 
         private void Page_Loaded(object sender, RoutedEventArgs e)
         {
@@ -155,6 +157,9 @@ private void Page_Loaded(object sender, RoutedEventArgs e)
                 App.CurrentInstance = this as IShellPage;
             }
 
+            viewModel = new ItemViewModel();
+            interactionOperation = new Interaction();
+
             switch (NavParams)
             {
                 case "Start":