2nd round

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/ContentPageViewModel.cs

@@ -264,6 +264,17 @@ public partial class ContentPageViewModel : PageViewModel, ICommandBarContext
         if (model != null)
         {
             model.ItemsChanged -= Model_ItemsChanged;
+            if (model is IDisposable disposableModel)
+            {
+                try
+                {
+                    disposableModel.Dispose();
+                }
+                catch
+                {
+                    // Ignore exceptions during cleanup
+                }
+            }
         }
     }
 }

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/ListViewModel.cs

@@ -571,6 +571,17 @@ public partial class ListViewModel : PageViewModel, IDisposable
         if (model != null)
         {
             model.ItemsChanged -= Model_ItemsChanged;
+            if (model is IDisposable disposableModel)
+            {
+                try
+                {
+                    disposableModel.Dispose();
+                }
+                catch
+                {
+                    // Ignore exceptions during cleanup
+                }
+            }
         }
     }
 }

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/PageViewModel.cs

@@ -243,6 +243,17 @@ public partial class PageViewModel : ExtensionObjectViewModel, IPageContext
         if (model != null)
         {
             model.PropChanged -= Model_PropChanged;
+            if (model is IDisposable disposableModel)
+            {
+                try
+                {
+                    disposableModel.Dispose();
+                }
+                catch
+                {
+                    // Ignore exceptions during cleanup
+                }
+            }
         }
     }
 }

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/ShellViewModel.cs

@@ -18,7 +18,7 @@ using WinRT;
 
 namespace Microsoft.CmdPal.UI.ViewModels;
 
-public partial class ShellViewModel(IServiceProvider _serviceProvider, TaskScheduler _scheduler) : ObservableObject
+public partial class ShellViewModel(IServiceProvider _serviceProvider, TaskScheduler _scheduler) : ObservableObject, IDisposable
 {
     [ObservableProperty]
     public partial bool IsLoaded { get; set; } = false;
@@ -31,6 +31,8 @@ public partial class ShellViewModel(IServiceProvider _serviceProvider, TaskSched
 
     private PageViewModel _currentPage = new LoadingPageViewModel(null, _scheduler);
 
+    private bool _isDisposed;
+
     public PageViewModel CurrentPage
     {
         get => _currentPage;
@@ -201,6 +203,48 @@ public partial class ShellViewModel(IServiceProvider _serviceProvider, TaskSched
         SetActiveExtension(null);
     }
 
+    protected virtual void Dispose(bool disposing)
+    {
+        if (!_isDisposed)
+        {
+            _isDisposed = true;
+            if (disposing)
+            {
+                // Dispose managed resources
+                if (_mainListPage is IDisposable disposable)
+                {
+                    try
+                    {
+                        disposable.Dispose();
+                    }
+                    catch (Exception)
+                    {
+                    }
+                }
+
+                if (_currentPage is IDisposable disposablePage)
+                {
+                    try
+                    {
+                        disposablePage.Dispose();
+                    }
+                    catch
+                    {
+                    }
+                }
+
+                _mainListPage = null;
+                _activeExtension = null;
+            }
+        }
+    }
+
+    public void Dispose()
+    {
+        Dispose(true);
+        GC.SuppressFinalize(this);
+    }
+
     // You may ask yourself, why aren't we using CsWin32 for this?
     // The CsWin32 projected version includes some object marshalling, like so:
     //

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Indexer/FallbackOpenFileItem.cs

@@ -21,6 +21,8 @@ internal sealed partial class FallbackOpenFileItem : FallbackCommandItem, System
 
     private uint _queryCookie = 10;
 
+    private bool _isDisposed;
+
     public FallbackOpenFileItem()
         : base(new NoOpCommand(), Resources.Indexer_Find_Path_fallback_display_title)
     {
@@ -120,9 +122,17 @@ internal sealed partial class FallbackOpenFileItem : FallbackCommandItem, System
         }
     }
 
-    public void Dispose()
+    protected override void Dispose(bool disposing)
     {
-        _searchEngine.Dispose();
-        GC.SuppressFinalize(this);
+        if (!_isDisposed)
+        {
+            _isDisposed = true;
+            if (disposing)
+            {
+                _searchEngine?.Dispose();
+            }
+        }
+
+        base.Dispose(disposing);
     }
 }

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Indexer/Pages/ActionsListContextItem.cs

@@ -21,6 +21,7 @@ internal sealed partial class ActionsListContextItem : CommandContextItem, IDisp
 {
     private readonly string fullPath;
     private readonly List<CommandContextItem> actions = [];
+    private bool _isDisposed;
     private static readonly Lock UpdateMoreCommandsLock = new();
     private static ActionRuntime actionRuntime;
 
@@ -97,14 +98,24 @@ internal sealed partial class ActionsListContextItem : CommandContextItem, IDisp
         }
     }
 
-    public void Dispose()
+    protected override void Dispose(bool disposing)
     {
-        lock (UpdateMoreCommandsLock)
+        if (!_isDisposed)
         {
-            if (actionRuntime != null)
+            _isDisposed = true;
+            if (disposing)
             {
-                actionRuntime.ActionCatalog.Changed -= ActionCatalog_Changed;
+                lock (UpdateMoreCommandsLock)
+                {
+                    if (actionRuntime != null)
+                    {
+                        actionRuntime.ActionCatalog.Changed -= ActionCatalog_Changed;
+                        actionRuntime = null;
+                    }
+                }
             }
         }
+
+        base.Dispose(disposing);
     }
 }

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Indexer/Pages/IndexerPage.cs

@@ -21,6 +21,8 @@ internal sealed partial class IndexerPage : DynamicListPage, IDisposable
 
     private string initialQuery = string.Empty;
 
+    private bool _isDisposed;
+
     public IndexerPage()
     {
         Id = "com.microsoft.indexer.fileSearch";
@@ -33,6 +35,7 @@ internal sealed partial class IndexerPage : DynamicListPage, IDisposable
 
     public IndexerPage(string query, SearchEngine searchEngine, uint queryCookie, IList<IListItem> firstPageData)
     {
+        disposeSearchEngine = false;
         Icon = Icons.FileExplorer;
         Name = Resources.Indexer_Title;
         _searchEngine = searchEngine;
@@ -40,7 +43,6 @@ internal sealed partial class IndexerPage : DynamicListPage, IDisposable
         _indexerListItems.AddRange(firstPageData);
         initialQuery = query;
         SearchText = query;
-        disposeSearchEngine = false;
     }
 
     public override void UpdateSearchText(string oldSearch, string newSearch)
@@ -76,12 +78,21 @@ internal sealed partial class IndexerPage : DynamicListPage, IDisposable
         _searchEngine.Query(query, _queryCookie);
     }
 
-    public void Dispose()
+    protected override void Dispose(bool disposing)
     {
-        if (disposeSearchEngine)
+        if (!_isDisposed)
         {
-            _searchEngine.Dispose();
-            GC.SuppressFinalize(this);
+            _isDisposed = true;
+
+            if (disposing)
+            {
+                if (disposeSearchEngine)
+                {
+                    _searchEngine?.Dispose();
+                }
+            }
         }
+
+        base.Dispose(disposing);
     }
 }

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.WinGet/Pages/WinGetExtensionPage.cs

@@ -34,6 +34,8 @@ internal sealed partial class WinGetExtensionPage : DynamicListPage, IDisposable
 
     private IEnumerable<CatalogPackage>? _results;
 
+    private bool _disposed;
+
     public static IconInfo WinGetIcon { get; } = IconHelpers.FromRelativePath("Assets\\WinGet.svg");
 
     public static IconInfo ExtensionsIcon { get; } = IconHelpers.FromRelativePath("Assets\\Extension.svg");
@@ -189,7 +191,7 @@ internal sealed partial class WinGetExtensionPage : DynamicListPage, IDisposable
             return [];
         }
 
-        string searchDebugText = $"{query}{(HasTag ? "+" : string.Empty)}{_tag}";
+        var searchDebugText = $"{query}{(HasTag ? "+" : string.Empty)}{_tag}";
         Logger.LogDebug($"Starting search for '{searchDebugText}'");
         HashSet<CatalogPackage> results = new(new PackageIdCompare());
 
@@ -271,7 +273,19 @@ internal sealed partial class WinGetExtensionPage : DynamicListPage, IDisposable
         return results;
     }
 
-    public void Dispose() => throw new NotImplementedException();
+    protected override void Dispose(bool disposing)
+    {
+        if (!_disposed)
+        {
+            _disposed = true;
+            if (disposing)
+            {
+                _cancellationTokenSource?.Dispose();
+            }
+        }
+
+        base.Dispose(disposing);
+    }
 }
 
 [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.MaintainabilityRules", "SA1402:File may only contain a single type", Justification = "I just like it")]

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.WindowWalker/Pages/WindowWalkerListPage.cs

@@ -46,21 +46,17 @@ internal sealed partial class WindowWalkerListPage : DynamicListPage, IDisposabl
 
     public override IListItem[] GetItems() => Query(SearchText).ToArray();
 
-    public void Dispose()
-    {
-        Dispose(disposing: true);
-        GC.SuppressFinalize(this);
-    }
-
-    public void Dispose(bool disposing)
+    protected override void Dispose(bool disposing)
     {
         if (!_disposed)
         {
+            _disposed = true;
             if (disposing)
             {
                 _cancellationTokenSource?.Dispose();
-                _disposed = true;
             }
         }
+
+        base.Dispose(disposing);
     }
 }

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/BaseObservable.cs

@@ -10,12 +10,39 @@ namespace Microsoft.CommandPalette.Extensions.Toolkit;
 // asynchronously, so as to not block the extension app while it's being
 // processed in the host app.
 // (also consider this for ItemsChanged in ListPage)
-public partial class BaseObservable : INotifyPropChanged
+public partial class BaseObservable : INotifyPropChanged, IDisposable
 {
+    private bool _isDisposed;
+
     public event TypedEventHandler<object, IPropChangedEventArgs>? PropChanged;
 
+    // Protected implementation of Dispose pattern.
+    protected virtual void Dispose(bool disposing)
+    {
+        if (!_isDisposed)
+        {
+            _isDisposed = true;
+
+            if (disposing)
+            {
+                PropChanged = null;
+            }
+        }
+    }
+
+    public void Dispose()
+    {
+        Dispose(true);
+        GC.SuppressFinalize(this);
+    }
+
     protected void OnPropertyChanged(string propertyName)
     {
+        if (_isDisposed)
+        {
+            return;
+        }
+
         try
         {
             // TODO #181 - This is dangerous! If the original host goes away,

src/modules/cmdpal/extensionsdk/Microsoft.CommandPalette.Extensions.Toolkit/ListPage.cs

@@ -6,7 +6,7 @@ using Windows.Foundation;
 
 namespace Microsoft.CommandPalette.Extensions.Toolkit;
 
-public partial class ListPage : Page, IListPage
+public partial class ListPage : Page, IListPage, IDisposable
 {
     private string _placeholderText = string.Empty;
     private string _searchText = string.Empty;
@@ -15,6 +15,7 @@ public partial class ListPage : Page, IListPage
     private IFilters? _filters;
     private IGridProperties? _gridProperties;
     private ICommandItem? _emptyContent;
+    private bool _isDisposed;
 
     public event TypedEventHandler<object, IItemsChangedEventArgs>? ItemsChanged;
 
@@ -94,8 +95,28 @@ public partial class ListPage : Page, IListPage
     {
     }
 
+    protected override void Dispose(bool disposing)
+    {
+        if (!_isDisposed)
+        {
+            _isDisposed = true;
+
+            if (disposing)
+            {
+                ItemsChanged = null;
+            }
+        }
+
+        base.Dispose(disposing);
+    }
+
     protected void RaiseItemsChanged(int totalItems = -1)
     {
+        if (_isDisposed)
+        {
+            return;
+        }
+
         try
         {
             // TODO #181 - This is the same thing that BaseObservable has to deal with.