🧱 Mason: [structural improvement] (#308)

* Move DragItemsCompleted logic to ViewModels using x:Bind

* Remove dead code and add test for PersistFolderSequence

---------

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

Author: google-labs-jules[bot]

Launchbox.Tests/SettingsViewModelTests.cs

@@ -352,7 +352,7 @@ public async Task Dispose_WhileToggleInFlight_DoesNotThrow()
     }
 
     [Fact]
-    public void SetFolderSequence_ReordersAndRefreshesFolders()
+    public void PersistFolderSequence_ReordersAndRefreshesFolders()
     {
         var store = new MockSettingsStore();
         var folders = new System.Collections.Generic.List<ShortcutFolder>
@@ -368,11 +368,19 @@ public void SetFolderSequence_ReordersAndRefreshesFolders()
             new ShortcutFolderManager(store));
         var vm = new SettingsViewModel(settingsService, new MockWindowService(), new MockFilePickerService(), new MockDispatcher());
 
-        vm.SetFolderSequence([@"C:\Desktop\B", @"C:\Desktop\A"]);
+        // Simulate ListView reordering the underlying collection directly
+        var folderA = vm.Folders[0];
+        var folderB = vm.Folders[1];
+        vm.Folders.Clear();
+        vm.Folders.Add(folderB);
+        vm.Folders.Add(folderA);
 
-        Assert.Equal(2, vm.Folders.Count);
-        Assert.Equal("B", vm.Folders[0].Label);
-        Assert.Equal("A", vm.Folders[1].Label);
+        vm.PersistFolderSequence();
+
+        var updatedFolders = settingsService.GetShortcutFolders();
+        Assert.Equal(2, updatedFolders.Count);
+        Assert.Equal("B", updatedFolders[0].Label);
+        Assert.Equal("A", updatedFolders[1].Label);
     }
 
     [Fact]

MainWindow.xaml

@@ -143,7 +143,7 @@
                   CanReorderItems="{x:Bind ViewModel.IsFilterEmpty, Mode=OneWay}"
                   AllowDrop="{x:Bind ViewModel.IsFilterEmpty, Mode=OneWay}"
                   CanDragItems="{x:Bind ViewModel.IsFilterEmpty, Mode=OneWay}"
-                  DragItemsCompleted="AppGrid_DragItemsCompleted"
+                  DragItemsCompleted="{x:Bind ViewModel.PersistItemOrder}"
                   ItemTemplate="{StaticResource AppItemTemplate}">
         </GridView>
 

MainWindow.xaml.cs

@@ -264,17 +264,4 @@ private void Grid_CharacterReceived(UIElement sender, CharacterReceivedRoutedEve
         args.Handled = true;
     }
 
-    private void AppGrid_DragItemsCompleted(ListViewBase sender, DragItemsCompletedEventArgs args)
-    {
-        // FilteredApps is already in the new order — WinUI modified it in-place during drag.
-        // Persist the new order so it survives app restarts.
-        try
-        {
-            ViewModel.PersistItemOrder();
-        }
-        catch (Exception ex)
-        {
-            Trace.WriteLine($"Failed to persist item order: {PathSecurity.GetSafeExceptionMessage(ex)}");
-        }
-    }
 }

SettingsWindow.xaml

@@ -42,7 +42,7 @@
                           CanReorderItems="True"
                           AllowDrop="True"
                           CanDragItems="True"
-                          DragItemsCompleted="FolderList_DragItemsCompleted">
+                          DragItemsCompleted="{x:Bind ViewModel.PersistFolderSequence}">
                   <ListView.ItemTemplate>
                     <DataTemplate x:DataType="models:ShortcutFolder">
                       <Grid ColumnDefinitions="*,Auto,Auto,Auto,Auto" Padding="4" ColumnSpacing="4">

SettingsWindow.xaml.cs

@@ -48,9 +48,4 @@ private void SettingsWindow_Closed(object sender, WindowEventArgs args)
         ViewModel.Dispose();
     }
 
-    private void FolderList_DragItemsCompleted(ListViewBase sender, DragItemsCompletedEventArgs args)
-    {
-        var orderedPaths = sender.Items.OfType<ShortcutFolder>().Select(f => f.Path).ToList();
-        ViewModel.SetFolderSequence(orderedPaths);
-    }
 }

ViewModels/MainViewModel.cs

@@ -538,18 +538,25 @@ private void ToggleGroup(AppItemGroup? group)
     /// </summary>
     public void PersistItemOrder()
     {
-        var orders = FilteredApps
-            .GroupBy(a => a.FolderPath)
-            .ToDictionary(g => g.Key, g => g.Select(a => Path.GetFileName(a.Path)).ToList());
-        // Merge rather than replace: a folder that is currently unavailable (e.g. slow drive
-        // that failed to load) produces no items in FilteredApps and must not lose its saved order.
-        _settingsService.MergeItemOrders(orders);
-
-        // Sync Apps without triggering a redundant RebuildFilteredApps — FilteredApps == Apps
-        // when no filter is active (CanReorderItems is bound to IsFilterEmpty).
-        Apps.CollectionChanged -= Apps_CollectionChanged;
-        Apps.ReplaceAll(FilteredApps);
-        Apps.CollectionChanged += Apps_CollectionChanged;
+        try
+        {
+            var orders = FilteredApps
+                .GroupBy(a => a.FolderPath)
+                .ToDictionary(g => g.Key, g => g.Select(a => Path.GetFileName(a.Path)).ToList());
+            // Merge rather than replace: a folder that is currently unavailable (e.g. slow drive
+            // that failed to load) produces no items in FilteredApps and must not lose its saved order.
+            _settingsService.MergeItemOrders(orders);
+
+            // Sync Apps without triggering a redundant RebuildFilteredApps — FilteredApps == Apps
+            // when no filter is active (CanReorderItems is bound to IsFilterEmpty).
+            Apps.CollectionChanged -= Apps_CollectionChanged;
+            Apps.ReplaceAll(FilteredApps);
+            Apps.CollectionChanged += Apps_CollectionChanged;
+        }
+        catch (Exception ex)
+        {
+            Trace.WriteLine($"Failed to persist item order: {PathSecurity.GetSafeExceptionMessage(ex)}");
+        }
     }
 
     private void RebuildFolderWatchers(IReadOnlyList<ShortcutFolder> folders)

ViewModels/SettingsViewModel.cs

@@ -150,7 +150,18 @@ private async Task RenameFolderAsync(ShortcutFolder folder)
 
     private void ApplyRename(int order, string newLabel) => _settingsService.RenameShortcutFolder(order, newLabel);
 
-    public void SetFolderSequence(IReadOnlyList<string> orderedPaths) => _settingsService.SetShortcutFolderSequence(orderedPaths);
+    public void PersistFolderSequence()
+    {
+        try
+        {
+            var orderedPaths = Folders.Select(f => f.Path).ToList();
+            _settingsService.SetShortcutFolderSequence(orderedPaths);
+        }
+        catch (Exception ex)
+        {
+            Trace.WriteLine($"Failed to persist folder sequence: {PathSecurity.GetSafeExceptionMessage(ex)}");
+        }
+    }
 
     private void RefreshFolders()
     {