wip

src/modules/peek/Peek.FilePreviewer/FilePreview.xaml.cs

@@ -6,11 +6,11 @@ namespace Peek.FilePreviewer
 {
     using System;
     using System.Text;
-    using System.Threading;
     using System.Threading.Tasks;
     using CommunityToolkit.Mvvm.ComponentModel;
     using Microsoft.UI.Xaml;
     using Microsoft.UI.Xaml.Controls;
+    using Microsoft.UI.Xaml.Media.Imaging;
     using Peek.Common.Helpers;
     using Peek.Common.Models;
     using Peek.FilePreviewer.Models;
@@ -42,8 +42,6 @@ namespace Peek.FilePreviewer
         [ObservableProperty]
         private string imageInfoTooltip = ResourceLoader.GetForViewIndependentUse().GetString("PreviewTooltip_Blank");
 
-        private CancellationTokenSource _cancellationTokenSource = new ();
-
         public FilePreview()
         {
             InitializeComponent();
@@ -56,12 +54,8 @@ namespace Peek.FilePreviewer
             {
                 if (Previewer?.State == PreviewState.Error)
                 {
-                    // Cancel previous loading task
-                    _cancellationTokenSource.Cancel();
-                    _cancellationTokenSource = new ();
-
                     Previewer = previewerFactory.CreateDefaultPreviewer(File);
-                    await UpdatePreviewAsync(_cancellationTokenSource.Token);
+                    await UpdatePreviewAsync();
                 }
             }
         }
@@ -95,10 +89,6 @@ namespace Peek.FilePreviewer
 
         private async Task OnFilePropertyChanged()
         {
-            // Cancel previous loading task
-            _cancellationTokenSource.Cancel();
-            _cancellationTokenSource = new ();
-
             // TODO: track and cancel existing async preview tasks
             // https://github.com/microsoft/PowerToys/issues/22480
             if (File == null)
@@ -111,30 +101,20 @@ namespace Peek.FilePreviewer
             }
 
             Previewer = previewerFactory.Create(File);
-
-            await UpdatePreviewAsync(_cancellationTokenSource.Token);
+            await UpdatePreviewAsync();
         }
 
-        private async Task UpdatePreviewAsync(CancellationToken cancellationToken)
+        private async Task UpdatePreviewAsync()
         {
             if (Previewer != null)
             {
-                try
-                {
-                    cancellationToken.ThrowIfCancellationRequested();
-                    var size = await Previewer.GetPreviewSizeAsync(cancellationToken);
-                    SizeFormat windowSizeFormat = UnsupportedFilePreviewer != null ? SizeFormat.Percentage : SizeFormat.Pixels;
-                    PreviewSizeChanged?.Invoke(this, new PreviewSizeChangedArgs(size, windowSizeFormat));
-                    cancellationToken.ThrowIfCancellationRequested();
-                    await Previewer.LoadPreviewAsync(cancellationToken);
-                    cancellationToken.ThrowIfCancellationRequested();
-                    await UpdateImageTooltipAsync();
-                }
-                catch (OperationCanceledException)
-                {
-                    // TODO: Log task cancelled exception?
-                }
+                var size = await Previewer.GetPreviewSizeAsync();
+                SizeFormat windowSizeFormat = UnsupportedFilePreviewer != null ? SizeFormat.Percentage : SizeFormat.Pixels;
+                PreviewSizeChanged?.Invoke(this, new PreviewSizeChangedArgs(size, windowSizeFormat));
+                await Previewer.LoadPreviewAsync();
             }
+
+            await UpdateImageTooltipAsync();
         }
 
         partial void OnPreviewerChanging(IPreviewer? value)

src/modules/peek/Peek.FilePreviewer/Previewers/IPreviewer.cs

@@ -6,7 +6,6 @@ namespace Peek.FilePreviewer.Previewers
 {
     using System;
     using System.ComponentModel;
-    using System.Threading;
     using System.Threading.Tasks;
     using Windows.Foundation;
 
@@ -16,9 +15,9 @@ namespace Peek.FilePreviewer.Previewers
 
         public static bool IsFileTypeSupported(string fileExt) => throw new NotImplementedException();
 
-        public Task<Size> GetPreviewSizeAsync(CancellationToken cancellationToken);
+        public Task<Size> GetPreviewSizeAsync();
 
-        Task LoadPreviewAsync(CancellationToken cancellationToken);
+        Task LoadPreviewAsync();
     }
 
     public enum PreviewState

src/modules/peek/Peek.FilePreviewer/Previewers/ImagePreviewer/Helpers/PropertyHelper.cs

@@ -5,7 +5,6 @@
 namespace Peek.FilePreviewer.Previewers
 {
     using System;
-    using System.Diagnostics;
     using System.Runtime.InteropServices;
     using System.Threading.Tasks;
     using Peek.Common.Models;
@@ -17,21 +16,14 @@ namespace Peek.FilePreviewer.Previewers
         {
             return Task.Run(() =>
             {
-                try
+                var propertyStore = PropertyStoreShellApi.GetPropertyStoreFromPath(filePath, PropertyStoreShellApi.PropertyStoreFlags.OPENSLOWITEM);
+                if (propertyStore != null)
                 {
-                    var propertyStore = PropertyStoreShellApi.GetPropertyStoreFromPath(filePath, PropertyStoreShellApi.PropertyStoreFlags.OPENSLOWITEM);
-                    if (propertyStore != null)
-                    {
-                        var width = (int)PropertyStoreShellApi.GetUIntFromPropertyStore(propertyStore, PropertyStoreShellApi.PropertyKey.ImageHorizontalSize);
-                        var height = (int)PropertyStoreShellApi.GetUIntFromPropertyStore(propertyStore, PropertyStoreShellApi.PropertyKey.ImageVerticalSize);
+                    var width = (int)PropertyStoreShellApi.GetUIntFromPropertyStore(propertyStore, PropertyStoreShellApi.PropertyKey.ImageHorizontalSize);
+                    var height = (int)PropertyStoreShellApi.GetUIntFromPropertyStore(propertyStore, PropertyStoreShellApi.PropertyKey.ImageVerticalSize);
 
-                        Marshal.ReleaseComObject(propertyStore);
-                        return new Size(width, height);
-                    }
-                }
-                catch (Exception e)
-                {
-                    Debug.Write("Error getting image dimensions:\n" + e.ToString());
+                    Marshal.ReleaseComObject(propertyStore);
+                    return new Size(width, height);
                 }
 
                 return Size.Empty;
@@ -41,19 +33,12 @@ namespace Peek.FilePreviewer.Previewers
         public static Task<ulong> GetFileSizeInBytes(string filePath)
         {
             ulong bytes = 0;
-            try
+            var propertyStore = PropertyStoreShellApi.GetPropertyStoreFromPath(filePath, PropertyStoreShellApi.PropertyStoreFlags.OPENSLOWITEM);
+            if (propertyStore != null)
             {
-                var propertyStore = PropertyStoreShellApi.GetPropertyStoreFromPath(filePath, PropertyStoreShellApi.PropertyStoreFlags.OPENSLOWITEM);
-                if (propertyStore != null)
-                {
-                    bytes = PropertyStoreShellApi.GetULongFromPropertyStore(propertyStore, PropertyStoreShellApi.PropertyKey.FileSizeBytes);
+                bytes = PropertyStoreShellApi.GetULongFromPropertyStore(propertyStore, PropertyStoreShellApi.PropertyKey.FileSizeBytes);
 
-                    Marshal.ReleaseComObject(propertyStore);
-                }
-            }
-            catch (Exception e)
-            {
-                Debug.WriteLine("Error getting folder item size:\n", e.ToString());
+                Marshal.ReleaseComObject(propertyStore);
             }
 
             return Task.FromResult(bytes);
@@ -62,20 +47,13 @@ namespace Peek.FilePreviewer.Previewers
         public static Task<string> GetFileType(string filePath)
         {
             var type = string.Empty;
-            try
+            var propertyStore = PropertyStoreShellApi.GetPropertyStoreFromPath(filePath, PropertyStoreShellApi.PropertyStoreFlags.OPENSLOWITEM);
+            if (propertyStore != null)
             {
-                var propertyStore = PropertyStoreShellApi.GetPropertyStoreFromPath(filePath, PropertyStoreShellApi.PropertyStoreFlags.OPENSLOWITEM);
-                if (propertyStore != null)
-                {
-                    // TODO: find a way to get user friendly description
-                    type = PropertyStoreShellApi.GetStringFromPropertyStore(propertyStore, PropertyStoreShellApi.PropertyKey.FileType);
+                // TODO: find a way to get user friendly description
+                type = PropertyStoreShellApi.GetStringFromPropertyStore(propertyStore, PropertyStoreShellApi.PropertyKey.FileType);
 
-                    Marshal.ReleaseComObject(propertyStore);
-                }
-            }
-            catch (Exception e)
-            {
-                Debug.WriteLine("Failed to get file type:\n" + e.ToString());
+                Marshal.ReleaseComObject(propertyStore);
             }
 
             return Task.FromResult(type);

src/modules/peek/Peek.FilePreviewer/Previewers/ImagePreviewer/ImagePreviewer.cs

@@ -49,14 +49,18 @@ namespace Peek.FilePreviewer.Previewers
 
         private bool IsFullImageLoaded => FullQualityImageTask?.Status == TaskStatus.RanToCompletion;
 
+        private CancellationTokenSource _cancellationTokenSource = new CancellationTokenSource();
+
+        private CancellationToken CancellationToken => _cancellationTokenSource.Token;
+
         public void Dispose()
         {
+            _cancellationTokenSource.Dispose();
             GC.SuppressFinalize(this);
         }
 
-        public async Task<Size> GetPreviewSizeAsync(CancellationToken cancellationToken)
+        public async Task<Size> GetPreviewSizeAsync()
         {
-            cancellationToken.ThrowIfCancellationRequested();
             var propertyImageSize = await PropertyHelper.GetImageSize(File.Path);
             if (propertyImageSize != Size.Empty)
             {
@@ -66,14 +70,13 @@ namespace Peek.FilePreviewer.Previewers
             return await WICHelper.GetImageSize(File.Path);
         }
 
-        public async Task LoadPreviewAsync(CancellationToken cancellationToken)
+        public async Task LoadPreviewAsync()
         {
             State = PreviewState.Loading;
 
-            LowQualityThumbnailTask = LoadLowQualityThumbnailAsync(cancellationToken);
-            HighQualityThumbnailTask = LoadHighQualityThumbnailAsync(cancellationToken);
-            FullQualityImageTask = LoadFullQualityImageAsync(cancellationToken);
-            cancellationToken.ThrowIfCancellationRequested();
+            LowQualityThumbnailTask = LoadLowQualityThumbnailAsync();
+            HighQualityThumbnailTask = LoadHighQualityThumbnailAsync();
+            FullQualityImageTask = LoadFullQualityImageAsync();
 
             await Task.WhenAll(LowQualityThumbnailTask, HighQualityThumbnailTask, FullQualityImageTask);
 
@@ -94,11 +97,15 @@ namespace Peek.FilePreviewer.Previewers
             }
         }
 
-        private Task<bool> LoadLowQualityThumbnailAsync(CancellationToken cancellationToken)
+        private Task<bool> LoadLowQualityThumbnailAsync()
         {
             return TaskExtension.RunSafe(async () =>
             {
-                cancellationToken.ThrowIfCancellationRequested();
+                if (CancellationToken.IsCancellationRequested)
+                {
+                    _cancellationTokenSource = new CancellationTokenSource();
+                    return;
+                }
 
                 if (!IsFullImageLoaded && !IsHighQualityThumbnailLoaded)
                 {
@@ -110,23 +117,24 @@ namespace Peek.FilePreviewer.Previewers
                         throw new ArgumentNullException(nameof(hbitmap));
                     }
 
-                    cancellationToken.ThrowIfCancellationRequested();
-
                     await Dispatcher.RunOnUiThread(async () =>
                     {
-                        cancellationToken.ThrowIfCancellationRequested();
-                        var thumbnailBitmap = await GetBitmapFromHBitmapAsync(hbitmap, cancellationToken);
+                        var thumbnailBitmap = await GetBitmapFromHBitmapAsync(hbitmap);
                         Preview = thumbnailBitmap;
                     });
                 }
             });
         }
 
-        private Task<bool> LoadHighQualityThumbnailAsync(CancellationToken cancellationToken)
+        private Task<bool> LoadHighQualityThumbnailAsync()
         {
             return TaskExtension.RunSafe(async () =>
             {
-                cancellationToken.ThrowIfCancellationRequested();
+                if (CancellationToken.IsCancellationRequested)
+                {
+                    _cancellationTokenSource = new CancellationTokenSource();
+                    return;
+                }
 
                 if (!IsFullImageLoaded)
                 {
@@ -138,29 +146,29 @@ namespace Peek.FilePreviewer.Previewers
                         throw new ArgumentNullException(nameof(hbitmap));
                     }
 
-                    cancellationToken.ThrowIfCancellationRequested();
-
                     await Dispatcher.RunOnUiThread(async () =>
                     {
-                        cancellationToken.ThrowIfCancellationRequested();
-                        var thumbnailBitmap = await GetBitmapFromHBitmapAsync(hbitmap, cancellationToken);
+                        var thumbnailBitmap = await GetBitmapFromHBitmapAsync(hbitmap);
                         Preview = thumbnailBitmap;
                     });
                 }
             });
         }
 
-        private Task<bool> LoadFullQualityImageAsync(CancellationToken cancellationToken)
+        private Task<bool> LoadFullQualityImageAsync()
         {
             return TaskExtension.RunSafe(async () =>
             {
-                cancellationToken.ThrowIfCancellationRequested();
+                if (CancellationToken.IsCancellationRequested)
+                {
+                    _cancellationTokenSource = new CancellationTokenSource();
+                    return;
+                }
 
                 // TODO: Check if this is performant
                 await Dispatcher.RunOnUiThread(async () =>
                 {
-                    cancellationToken.ThrowIfCancellationRequested();
-                    var bitmap = await GetFullBitmapFromPathAsync(File.Path, cancellationToken);
+                    var bitmap = await GetFullBitmapFromPathAsync(File.Path);
                     Preview = bitmap;
                 });
             });
@@ -175,34 +183,27 @@ namespace Peek.FilePreviewer.Previewers
             return hasFailedLoadingLowQualityThumbnail && hasFailedLoadingHighQualityThumbnail && hasFailedLoadingFullQualityImage;
         }
 
-        private static async Task<BitmapImage> GetFullBitmapFromPathAsync(string path, CancellationToken cancellationToken)
+        private static async Task<BitmapImage> GetFullBitmapFromPathAsync(string path)
         {
             var bitmap = new BitmapImage();
-
-            cancellationToken.ThrowIfCancellationRequested();
             using (FileStream stream = System.IO.File.OpenRead(path))
             {
-                cancellationToken.ThrowIfCancellationRequested();
                 await bitmap.SetSourceAsync(stream.AsRandomAccessStream());
             }
 
             return bitmap;
         }
 
-        private static async Task<BitmapSource> GetBitmapFromHBitmapAsync(IntPtr hbitmap, CancellationToken cancellationToken)
+        private static async Task<BitmapSource> GetBitmapFromHBitmapAsync(IntPtr hbitmap)
         {
             try
             {
                 var bitmap = System.Drawing.Image.FromHbitmap(hbitmap);
                 var bitmapImage = new BitmapImage();
-
-                cancellationToken.ThrowIfCancellationRequested();
                 using (var stream = new MemoryStream())
                 {
                     bitmap.Save(stream, ImageFormat.Bmp);
                     stream.Position = 0;
-
-                    cancellationToken.ThrowIfCancellationRequested();
                     await bitmapImage.SetSourceAsync(stream.AsRandomAccessStream());
                 }
 

src/modules/peek/Peek.FilePreviewer/Previewers/PngPreviewer/PngPreviewer.cs

@@ -5,16 +5,18 @@
 namespace Peek.FilePreviewer.Previewers
 {
     using System;
+    using System.Collections.Generic;
+    using System.Drawing.Imaging;
     using System.IO;
     using System.Threading;
     using System.Threading.Tasks;
     using CommunityToolkit.Mvvm.ComponentModel;
     using Microsoft.UI.Dispatching;
     using Microsoft.UI.Xaml.Media.Imaging;
-    using Peek.Common.Extensions;
+    using Peek.Common;
     using Windows.Foundation;
     using Windows.Graphics.Imaging;
-    using Windows.Storage;
+    using Windows.Storage.Streams;
     using File = Peek.Common.Models.File;
 
     public partial class PngPreviewer : ObservableObject, IBitmapPreviewer
@@ -42,23 +44,17 @@ namespace Peek.FilePreviewer.Previewers
 
         private DispatcherQueue Dispatcher { get; }
 
-        private Task<bool>? PreviewQualityThumbnailTask { get; set; }
-
-        private Task<bool>? FullQualityImageTask { get; set; }
-
         private CancellationTokenSource _cancellationTokenSource = new CancellationTokenSource();
 
         private CancellationToken CancellationToken => _cancellationTokenSource.Token;
 
-        private bool IsFullImageLoaded => FullQualityImageTask?.Status == TaskStatus.RanToCompletion;
-
         public void Dispose()
         {
             _cancellationTokenSource.Dispose();
             GC.SuppressFinalize(this);
         }
 
-        public async Task<Size> GetPreviewSizeAsync(CancellationToken cancellationToken)
+        public async Task<Size> GetPreviewSizeAsync()
         {
             var propertyImageSize = await PropertyHelper.GetImageSize(File.Path);
             if (propertyImageSize != Size.Empty)
@@ -69,14 +65,13 @@ namespace Peek.FilePreviewer.Previewers
             return await WICHelper.GetImageSize(File.Path);
         }
 
-        public async Task LoadPreviewAsync(CancellationToken cancellationToken)
+        public async Task LoadPreviewAsync()
         {
             State = PreviewState.Loading;
 
-            PreviewQualityThumbnailTask = LoadPreviewImageAsync();
-            FullQualityImageTask = LoadFullImageAsync();
+            var previewTask = LoadPreviewImageAsync();
 
-            await Task.WhenAll(PreviewQualityThumbnailTask, FullQualityImageTask);
+            await Task.WhenAll(previewTask);
 
             if (Preview == null)
             {
@@ -100,10 +95,10 @@ namespace Peek.FilePreviewer.Previewers
             }
         }
 
-        private Task<bool> LoadPreviewImageAsync()
+        private Task LoadPreviewImageAsync()
         {
             var thumbnailTCS = new TaskCompletionSource();
-            return TaskExtension.RunSafe(async () =>
+            Dispatcher.TryEnqueue(async () =>
             {
                 if (CancellationToken.IsCancellationRequested)
                 {
@@ -111,51 +106,12 @@ namespace Peek.FilePreviewer.Previewers
                     return;
                 }
 
-                if (!IsFullImageLoaded)
-                {
-                    await Dispatcher.RunOnUiThread(async () =>
-                    {
-                        Preview = await ThumbnailHelper.GetThumbnailAsync(File.Path, _png_image_size);
-                    });
-                }
+                Preview = await ThumbnailHelper.GetThumbnailAsync(File.Path, _png_image_size);
+
+                thumbnailTCS.SetResult();
             });
-        }
 
-        private Task<bool> LoadFullImageAsync()
-        {
-            var thumbnailTCS = new TaskCompletionSource();
-            return TaskExtension.RunSafe(async () =>
-            {
-                if (CancellationToken.IsCancellationRequested)
-                {
-                    _cancellationTokenSource = new CancellationTokenSource();
-                    return;
-                }
-
-                await Dispatcher.RunOnUiThread(async () =>
-                {
-                    WriteableBitmap? bitmap = null;
-
-                    var sFile = await StorageFile.GetFileFromPathAsync(File.Path);
-                    using (var randomAccessStream = await sFile.OpenStreamForReadAsync())
-                    {
-                        // Create an encoder with the desired format
-                        var decoder = await BitmapDecoder.CreateAsync(
-                            BitmapDecoder.PngDecoderId,
-                            randomAccessStream.AsRandomAccessStream());
-
-                        var softwareBitmap = await decoder.GetSoftwareBitmapAsync(
-                            BitmapPixelFormat.Bgra8,
-                            BitmapAlphaMode.Premultiplied);
-
-                        // full quality image
-                        bitmap = new WriteableBitmap((int)decoder.PixelWidth, (int)decoder.PixelHeight);
-                        softwareBitmap?.CopyToBuffer(bitmap.PixelBuffer);
-                    }
-
-                    Preview = bitmap;
-                });
-            });
+            return thumbnailTCS.Task;
         }
     }
 }

src/modules/peek/Peek.FilePreviewer/Previewers/PreviewerFactory.cs

@@ -4,7 +4,6 @@
 
 namespace Peek.FilePreviewer.Previewers
 {
-    using System.Threading;
     using Peek.Common.Models;
 
     public class PreviewerFactory

src/modules/peek/Peek.FilePreviewer/Previewers/UnsupportedFilePreviewer/UnsupportedFilePreviewer.cs

@@ -70,16 +70,21 @@ namespace Peek.FilePreviewer.Previewers
 
         private DispatcherQueue Dispatcher { get; }
 
+        private CancellationTokenSource _cancellationTokenSource = new CancellationTokenSource();
+
+        private CancellationToken CancellationToken => _cancellationTokenSource.Token;
+
         private Task<bool>? IconPreviewTask { get; set; }
 
         private Task<bool>? DisplayInfoTask { get; set; }
 
         public void Dispose()
         {
+            _cancellationTokenSource.Dispose();
             GC.SuppressFinalize(this);
         }
 
-        public Task<Size> GetPreviewSizeAsync(CancellationToken cancellationToken)
+        public Task<Size> GetPreviewSizeAsync()
         {
             return Task.Run(() =>
             {
@@ -87,14 +92,12 @@ namespace Peek.FilePreviewer.Previewers
             });
         }
 
-        public async Task LoadPreviewAsync(CancellationToken cancellationToken)
+        public async Task LoadPreviewAsync()
         {
-            cancellationToken.ThrowIfCancellationRequested();
-
             State = PreviewState.Loading;
 
-            IconPreviewTask = LoadIconPreviewAsync(cancellationToken);
-            DisplayInfoTask = LoadDisplayInfoAsync(cancellationToken);
+            IconPreviewTask = LoadIconPreviewAsync();
+            DisplayInfoTask = LoadDisplayInfoAsync();
 
             await Task.WhenAll(IconPreviewTask, DisplayInfoTask);
 
@@ -104,34 +107,38 @@ namespace Peek.FilePreviewer.Previewers
             }
         }
 
-        public Task<bool> LoadIconPreviewAsync(CancellationToken cancellationToken)
+        public Task<bool> LoadIconPreviewAsync()
         {
             return TaskExtension.RunSafe(async () =>
             {
-                cancellationToken.ThrowIfCancellationRequested();
+                if (CancellationToken.IsCancellationRequested)
+                {
+                    _cancellationTokenSource = new CancellationTokenSource();
+                    return;
+                }
 
                 // TODO: Get icon with transparency
                 IconHelper.GetIcon(Path.GetFullPath(File.Path), out IntPtr hbitmap);
-
-                cancellationToken.ThrowIfCancellationRequested();
                 await Dispatcher.RunOnUiThread(async () =>
                 {
-                    cancellationToken.ThrowIfCancellationRequested();
-                    var iconBitmap = await GetBitmapFromHBitmapAsync(hbitmap, cancellationToken);
+                    var iconBitmap = await GetBitmapFromHBitmapAsync(hbitmap);
                     IconPreview = iconBitmap;
                 });
             });
         }
 
-        public Task<bool> LoadDisplayInfoAsync(CancellationToken cancellationToken)
+        public Task<bool> LoadDisplayInfoAsync()
         {
             return TaskExtension.RunSafe(async () =>
             {
-                // File Properties
-                cancellationToken.ThrowIfCancellationRequested();
-                var bytes = await PropertyHelper.GetFileSizeInBytes(File.Path);
+                if (CancellationToken.IsCancellationRequested)
+                {
+                    _cancellationTokenSource = new CancellationTokenSource();
+                    return;
+                }
 
-                cancellationToken.ThrowIfCancellationRequested();
+                // File Properties
+                var bytes = await PropertyHelper.GetFileSizeInBytes(File.Path);
                 var type = await PropertyHelper.GetFileType(File.Path);
 
                 await Dispatcher.RunOnUiThread(() =>
@@ -162,22 +169,17 @@ namespace Peek.FilePreviewer.Previewers
             return hasFailedLoadingIconPreview && hasFailedLoadingDisplayInfo;
         }
 
-        // TODO: Move this to a helper file (ImagePreviewer uses the same code)
-        private static async Task<BitmapSource> GetBitmapFromHBitmapAsync(IntPtr hbitmap, CancellationToken cancellationToken)
+        // TODO: Move this to a helper file (ImagePrevier uses the same code)
+        private static async Task<BitmapSource> GetBitmapFromHBitmapAsync(IntPtr hbitmap)
         {
             try
             {
-                cancellationToken.ThrowIfCancellationRequested();
                 var bitmap = System.Drawing.Image.FromHbitmap(hbitmap);
                 var bitmapImage = new BitmapImage();
-
-                cancellationToken.ThrowIfCancellationRequested();
                 using (var stream = new MemoryStream())
                 {
                     bitmap.Save(stream, ImageFormat.Bmp);
                     stream.Position = 0;
-
-                    cancellationToken.ThrowIfCancellationRequested();
                     await bitmapImage.SetSourceAsync(stream.AsRandomAccessStream());
                 }
 

src/modules/peek/Peek.FilePreviewer/Previewers/WebBrowserPreviewer/WebBrowserPreviewer.cs

@@ -9,6 +9,8 @@ namespace Peek.FilePreviewer.Previewers
     using System.Threading;
     using System.Threading.Tasks;
     using CommunityToolkit.Mvvm.ComponentModel;
+    using Microsoft.UI.Dispatching;
+    using Peek.FilePreviewer.Controls;
     using Windows.Foundation;
     using File = Peek.Common.Models.File;
 
@@ -37,14 +39,14 @@ namespace Peek.FilePreviewer.Previewers
 
         private File File { get; }
 
-        public Task<Size> GetPreviewSizeAsync(CancellationToken cancellationToken)
+        public Task<Size> GetPreviewSizeAsync()
         {
             // TODO: define how to proper window size on HTML content.
             var size = new Size(1280, 720);
             return Task.FromResult(size);
         }
 
-        public Task LoadPreviewAsync(CancellationToken cancellationToken)
+        public Task LoadPreviewAsync()
         {
             State = PreviewState.Loading;
 

src/modules/peek/Peek.UI/FileSystem/FolderItemsQuery.cs

@@ -2,21 +2,17 @@
 // The Microsoft Corporation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-namespace Peek.UI
+namespace Peek.UI.FileSystem
 {
     using System;
     using System.Collections.Generic;
     using System.Diagnostics;
-    using System.Linq;
     using System.Threading;
     using System.Threading.Tasks;
     using CommunityToolkit.Mvvm.ComponentModel;
     using Microsoft.UI.Dispatching;
     using Peek.Common.Models;
-    using Peek.UI.FolderItemSources;
     using Peek.UI.Helpers;
-    using Windows.Storage;
-    using Windows.Storage.Search;
 
     public partial class FolderItemsQuery : ObservableObject
     {
@@ -28,7 +24,7 @@ namespace Peek.UI
         private File? currentFile;
 
         [ObservableProperty]
-        private int itemsCount = 0;
+        private List<File> files = new ();
 
         [ObservableProperty]
         private bool isMultiSelection;
@@ -38,66 +34,52 @@ namespace Peek.UI
 
         private CancellationTokenSource CancellationTokenSource { get; set; } = new CancellationTokenSource();
 
-        private Task? InitializeQueryTask { get; set; } = null;
+        private Task? InitializeFilesTask { get; set; } = null;
 
-        private IFolderItemsSource? FolderItemsSource { get; set; } = null;
-
-        // Must be called from UI thread
         public void Clear()
         {
             CurrentFile = null;
             IsMultiSelection = false;
 
-            if (InitializeQueryTask != null && InitializeQueryTask.Status == TaskStatus.Running)
+            if (InitializeFilesTask != null && InitializeFilesTask.Status == TaskStatus.Running)
             {
-                Debug.WriteLine("Detected existing InitializeQueryTask running. Cancelling it..");
+                Debug.WriteLine("Detected existing initializeFilesTask running. Cancelling it..");
                 CancellationTokenSource.Cancel();
             }
 
-            InitializeQueryTask = null;
+            InitializeFilesTask = null;
 
             lock (_mutateQueryDataLock)
             {
-                ItemsCount = 0; // TODO: can maybe move outside?
-                CurrentItemIndex = UninitializedItemIndex;
+                _dispatcherQueue.TryEnqueue(() =>
+                {
+                    Files = new List<File>();
+                    CurrentItemIndex = UninitializedItemIndex;
+                });
             }
         }
 
-        // Must be called from UI thread
-        public async Task UpdateCurrentItemIndex(int desiredIndex)
+        public void UpdateCurrentItemIndex(int desiredIndex)
         {
-            // TODO: add items count check
-            if (ItemsCount <= 1 || CurrentItemIndex == UninitializedItemIndex || FolderItemsSource == null ||
-                (InitializeQueryTask != null && InitializeQueryTask.Status == TaskStatus.Running))
+            if (Files.Count <= 1 || CurrentItemIndex == UninitializedItemIndex ||
+                (InitializeFilesTask != null && InitializeFilesTask.Status == TaskStatus.Running))
             {
                 return;
             }
 
             // Current index wraps around when reaching min/max folder item indices
-            desiredIndex %= itemsCount;
-            CurrentItemIndex = desiredIndex < 0 ? itemsCount + desiredIndex : desiredIndex;
+            desiredIndex %= Files.Count;
+            CurrentItemIndex = desiredIndex < 0 ? Files.Count + desiredIndex : desiredIndex;
 
-            if (CurrentItemIndex < 0 || CurrentItemIndex >= itemsCount)
+            if (CurrentItemIndex < 0 || CurrentItemIndex >= Files.Count)
             {
                 Debug.Assert(false, "Out of bounds folder item index detected.");
                 CurrentItemIndex = 0;
             }
 
-            if (FolderItemsSource == null)
-            {
-                return;
-            }
-
-            var temp = await FolderItemsSource.GetItemAt((uint)CurrentItemIndex); // TODO: fix uint declarations
-            if (temp != null)
-            {
-                Debug.WriteLine("Navigated to " + temp.FileName);
-            }
-
-            CurrentFile = temp;
+            CurrentFile = Files[CurrentItemIndex];
         }
 
-        // Must be called from UI thread
         public void Start()
         {
             var folderView = FileExplorerHelper.GetCurrentFolderView();
@@ -126,54 +108,75 @@ namespace Peek.UI
 
             try
             {
-                if (InitializeQueryTask != null && InitializeQueryTask.Status == TaskStatus.Running)
+                if (InitializeFilesTask != null && InitializeFilesTask.Status == TaskStatus.Running)
                 {
-                    Debug.WriteLine("Detected unexpected existing InitializeQueryTask running. Cancelling it..");
+                    Debug.WriteLine("Detected unexpected existing initializeFilesTask running. Cancelling it..");
                     CancellationTokenSource.Cancel();
                 }
 
                 CancellationTokenSource = new CancellationTokenSource();
-                InitializeQueryTask = new Task(() => InitializeQuery(folderView, items, firstSelectedItem, CancellationTokenSource.Token));
+                InitializeFilesTask = new Task(() => InitializeFiles(items, firstSelectedItem, CancellationTokenSource.Token));
 
                 // Execute file initialization/querying on background thread
-                InitializeQueryTask.Start();
+                InitializeFilesTask.Start();
             }
             catch (Exception e)
             {
-                Debug.WriteLine("Exception trying to run InitializeQueryTask:\n" + e.ToString());
+                Debug.WriteLine("Exception trying to run initializeFilesTask:\n" + e.ToString());
             }
         }
 
-        private async void InitializeQuery(
-            Shell32.IShellFolderViewDual3 folderView, // TODO: remove
+        // Finds index of firstSelectedItem either amongst folder items, initializing our internal File list
+        //  since storing Shell32.FolderItems as a field isn't reliable.
+        // Can take a few seconds for folders with 1000s of items; ensure it runs on a background thread.
+        //
+        // TODO optimization:
+        //  Handle case where selected items count > 1 separately. Although it'll still be slow for 1000s of items selected,
+        //  we can leverage faster APIs like Windows.Storage when 1 item is selected, and navigation is scoped to
+        //  the entire folder. We can then avoid iterating through all items here, and maintain a dynamic window of
+        //  loaded items around the current item index.
+        private void InitializeFiles(
             Shell32.FolderItems items,
             Shell32.FolderItem firstSelectedItem,
             CancellationToken cancellationToken)
         {
-            FolderItemsSource = IsMultiSelection ? new SelectedItemsSource() : new WholeFolderItemsSource();
+            var tempFiles = new List<File>(items.Count);
+            var tempCurIndex = UninitializedItemIndex;
 
-            InitialQueryData? initialQueryData = await FolderItemsSource.Initialize(folderView);
-            if (initialQueryData == null || !initialQueryData.HasValue)
+            for (int i = 0; i < items.Count; i++)
             {
+                cancellationToken.ThrowIfCancellationRequested();
+
+                var item = items.Item(i);
+                if (item == null)
+                {
+                    continue;
+                }
+
+                if (item.Name == firstSelectedItem.Name)
+                {
+                    tempCurIndex = i;
+                }
+
+                tempFiles.Add(new File(item.Path));
+            }
+
+            if (tempCurIndex == UninitializedItemIndex)
+            {
+                Debug.WriteLine("File query initialization: selectedItem index not found. Navigation remains disabled.");
                 return;
             }
 
-            InitialQueryData y = new ();
-            y.FirstItemIndex = 0;
-
             cancellationToken.ThrowIfCancellationRequested();
 
-            // Lock to prevent race conditions with UI thread's Clear calls upon Peek deactivation/hide
             lock (_mutateQueryDataLock)
             {
                 cancellationToken.ThrowIfCancellationRequested();
 
                 _dispatcherQueue.TryEnqueue(() =>
                 {
-                    cancellationToken.ThrowIfCancellationRequested();
-
-                    ItemsCount = (int)initialQueryData.Value.ItemsCount; // TODO: remove cast
-                    CurrentItemIndex = (int)initialQueryData.Value.FirstItemIndex;
+                    Files = tempFiles;
+                    CurrentItemIndex = tempCurIndex;
                 });
             }
         }

src/modules/peek/Peek.UI/FolderItemSources/IFolderItemsSource.cs

@@ -1,25 +0,0 @@
-// Copyright (c) Microsoft Corporation
-// The Microsoft Corporation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-namespace Peek.UI.FolderItemSources
-{
-    using System.Threading.Tasks;
-    using Peek.Common.Models;
-    using Shell32;
-
-    public interface IFolderItemsSource
-    {
-        // Result is null if no file at index
-        public Task<File?> GetItemAt(uint index);
-
-        public Task<InitialQueryData?> Initialize(IShellFolderViewDual3 folderView);
-    }
-
-    public struct InitialQueryData
-    {
-        public uint FirstItemIndex { get; set; }
-
-        public uint ItemsCount { get; set; }
-    }
-}

src/modules/peek/Peek.UI/FolderItemSources/SelectedItemsSource.cs

@@ -1,24 +0,0 @@
-// Copyright (c) Microsoft Corporation
-// The Microsoft Corporation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-namespace Peek.UI.FolderItemSources
-{
-    using System.Threading.Tasks;
-    using Peek.Common.Models;
-    using Shell32;
-
-    // Source of folder items for use when user activates Peek with multiple selected files
-    public class SelectedItemsSource : IFolderItemsSource
-    {
-        public Task<File?> GetItemAt(uint index)
-        {
-            throw new System.NotImplementedException();
-        }
-
-        public Task<InitialQueryData?> Initialize(IShellFolderViewDual3 folderView)
-        {
-            throw new System.NotImplementedException();
-        }
-    }
-}

src/modules/peek/Peek.UI/FolderItemSources/WholeFolderItemsSource.cs

@@ -1,112 +0,0 @@
-// Copyright (c) Microsoft Corporation
-// The Microsoft Corporation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-namespace Peek.UI.FolderItemSources
-{
-    using System;
-    using System.Collections.Generic;
-    using System.Diagnostics;
-    using System.Linq;
-    using System.Threading.Tasks;
-    using Peek.Common.Models;
-    using Shell32;
-    using Windows.Storage;
-    using Windows.Storage.Search;
-
-    // Provides folder items across an entire folder
-    public class WholeFolderItemsSource : IFolderItemsSource
-    {
-        private StorageItemQueryResult? ItemQuery { get; set; } = null;
-
-        public async Task<File?> GetItemAt(uint index)
-        {
-            if (ItemQuery == null)
-            {
-                return null;
-            }
-
-            IReadOnlyList<IStorageItem> items;
-            try
-            {
-                // ~1ms runtime on workstation w/ a debugger attached.
-                // TODO: further optimize by pre-fetching and maintaining a window of items.
-                //  There's a win32 API FindNextFile we could have used, but it doesn't allow fast, reverse iteration,
-                //  which is needed for backwards navigation.
-                items = await ItemQuery.GetItemsAsync(index, 1);
-                if (items == null || items.Count == 0)
-                {
-                    return null;
-                }
-            }
-            catch (Exception e)
-            {
-                Debug.WriteLine("Caught exception attempting to get file:\n", e.ToString());
-                return null;
-            }
-
-            // TODO: optimize by adding StorageItem as field to File class
-            return new File(items.First().Path);
-        }
-
-        public async Task<InitialQueryData?> Initialize(IShellFolderViewDual3 folderView)
-        {
-            try
-            {
-                var selectedItems = folderView.SelectedItems();
-                if (selectedItems == null || selectedItems.Count == 0)
-                {
-                    return null;
-                }
-
-                Debug.Assert(selectedItems.Count == 1, "SelectedItemsSource is intended for multi-item activations");
-
-                var selectedItem = selectedItems.Item(0);
-                var parent = System.IO.Directory.GetParent(selectedItem.Path); // TODO: try get directory name instead
-                if (parent == null)
-                {
-                    return null;
-                }
-
-                var folder = await StorageFolder.GetFolderFromPathAsync(parent.FullName);
-
-                // TODO: check if query options are supported (member helpers)
-                var queryOptions = new QueryOptions();
-                queryOptions.IndexerOption = IndexerOption.UseIndexerWhenAvailable;
-
-                // TODO: check if this clear is actually needed
-                Debug.WriteLine("count: " + queryOptions.SortOrder.Count);
-                queryOptions.SortOrder.Clear();
-
-                // TODO: fetch sort option
-                queryOptions.SortOrder.Add(new SortEntry("System.Size", false));
-
-                ItemQuery = folder.CreateItemQuery();
-                ItemQuery.ApplyNewQueryOptions(queryOptions);
-
-                Debug.WriteLine(selectedItem.Name);
-
-                // TODO: property passed in depends on sort order passed to query
-                var firstItemIndex = await ItemQuery.FindStartIndexAsync(selectedItem.Size);
-
-                // FindStartIndexAsync returns this when no item found
-                if (firstItemIndex == uint.MaxValue)
-                {
-                    Debug.WriteLine("File not found");
-                    return null;
-                }
-
-                InitialQueryData result = new ();
-
-                // TODO: pass & throw cancellation token (not essential, but may free thread resources earlier)
-                result.ItemsCount = await ItemQuery.GetItemCountAsync();
-                result.FirstItemIndex = firstItemIndex;
-                return result;
-            }
-            catch (Exception)
-            {
-                return null;
-            }
-        }
-    }
-}

src/modules/peek/Peek.UI/Helpers/FileExplorerHelper.cs

@@ -13,7 +13,7 @@ namespace Peek.UI.Helpers
 {
     public static class FileExplorerHelper
     {
-        public static Shell32.IShellFolderViewDual3? GetCurrentFolderView()
+        public static Shell32.IShellFolderViewDual2? GetCurrentFolderView()
         {
             var foregroundWindowHandle = NativeMethods.GetForegroundWindow();
 
@@ -26,7 +26,7 @@ namespace Peek.UI.Helpers
             var shell = new Shell32.Shell();
             foreach (SHDocVw.InternetExplorer window in shell.Windows())
             {
-                var shellFolderView = (Shell32.IShellFolderViewDual3)window.Document;
+                var shellFolderView = (Shell32.IShellFolderViewDual2)window.Document;
                 var folderTitle = shellFolderView.Folder.Title;
 
                 if (window.HWND == (int)foregroundWindowHandle && folderTitle == foregroundWindowTitle)

src/modules/peek/Peek.UI/MainWindow.xaml

@@ -32,7 +32,7 @@
             File="{x:Bind ViewModel.FolderItemsQuery.CurrentFile, Mode=OneWay}"
             FileIndex="{x:Bind ViewModel.FolderItemsQuery.CurrentItemIndex, Mode=OneWay}"
             IsMultiSelection="{x:Bind ViewModel.FolderItemsQuery.IsMultiSelection, Mode=OneWay}"
-            NumberOfFiles="{x:Bind ViewModel.FolderItemsQuery.ItemsCount, Mode=OneWay}" />
+            NumberOfFiles="{x:Bind ViewModel.FolderItemsQuery.Files.Count, Mode=OneWay}" />
 
         <fp:FilePreview
             Grid.Row="1"

src/modules/peek/Peek.UI/MainWindow.xaml.cs

@@ -12,6 +12,7 @@ namespace Peek.UI
     using Peek.UI.Extensions;
     using Peek.UI.Native;
     using Windows.Foundation;
+    using Windows.Win32;
     using WinUIEx;
 
     /// <summary>

src/modules/peek/Peek.UI/MainWindowViewModel.cs

@@ -7,12 +7,14 @@ namespace Peek.UI
     using System;
     using CommunityToolkit.Mvvm.ComponentModel;
     using Microsoft.UI.Xaml;
+    using Peek.UI.FileSystem;
 
     public partial class MainWindowViewModel : ObservableObject
     {
         private const int NavigationThrottleDelayMs = 100;
 
-        private bool IsNavigating { get; set; } = false;
+        [ObservableProperty]
+        private FolderItemsQuery _folderItemsQuery = new ();
 
         public MainWindowViewModel()
         {
@@ -20,31 +22,32 @@ namespace Peek.UI
             NavigationThrottleTimer.Interval = TimeSpan.FromMilliseconds(NavigationThrottleDelayMs);
         }
 
-        private async void AttemptNavigation(bool goToNextItem)
+        private DispatcherTimer NavigationThrottleTimer { get; set; } = new ();
+
+        public void AttemptLeftNavigation()
         {
-            if (NavigationThrottleTimer.IsEnabled && !IsNavigating)
+            if (NavigationThrottleTimer.IsEnabled)
             {
                 return;
             }
 
-            IsNavigating = true;
             NavigationThrottleTimer.Start();
 
-            var desiredItemIndex = FolderItemsQuery.CurrentItemIndex + (goToNextItem ? 1 : -1);
-
-            // TODO: return a bool so UI can give feedback in case navigation is unavailable?
-            await FolderItemsQuery.UpdateCurrentItemIndex(desiredItemIndex);
-            IsNavigating = false;
-        }
-
-        public void AttemptLeftNavigation()
-        {
-            AttemptNavigation(false);
+            // TODO: return a bool so UI can give feedback in case navigation is unavailable
+            FolderItemsQuery.UpdateCurrentItemIndex(FolderItemsQuery.CurrentItemIndex - 1);
         }
 
         public void AttemptRightNavigation()
         {
-            AttemptNavigation(true);
+            if (NavigationThrottleTimer.IsEnabled)
+            {
+                return;
+            }
+
+            NavigationThrottleTimer.Start();
+
+            // TODO: return a bool so UI can give feedback in case navigation is unavailable
+            FolderItemsQuery.UpdateCurrentItemIndex(FolderItemsQuery.CurrentItemIndex + 1);
         }
 
         private void NavigationThrottleTimer_Tick(object? sender, object e)
@@ -56,10 +59,5 @@ namespace Peek.UI
 
             ((DispatcherTimer)sender).Stop();
         }
-
-        [ObservableProperty]
-        private FolderItemsQuery _folderItemsQuery = new ();
-
-        private DispatcherTimer NavigationThrottleTimer { get; set; } = new ();
     }
 }

src/modules/peek/Peek.UI/Native/NativeMethods.cs

@@ -6,7 +6,6 @@ namespace Peek.UI.Native
 {
     using System;
     using System.Runtime.InteropServices;
-    using System.Runtime.Versioning;
     using System.Text;
     using Peek.Common.Models;
 
@@ -21,37 +20,6 @@ namespace Peek.UI.Native
         internal const int WM_SYSCOMMAND = 0x0112;
         internal const int SC_RESTORE = 0xF120;
 
-        [Flags]
-        public enum AssocF
-        {
-            None = 0,
-            Init_NoRemapCLSID = 0x1,
-            Init_ByExeName = 0x2,
-            Open_ByExeName = 0x2,
-            Init_DefaultToStar = 0x4,
-            Init_DefaultToFolder = 0x8,
-            NoUserSettings = 0x10,
-            NoTruncate = 0x20,
-            Verify = 0x40,
-            RemapRunDll = 0x80,
-            NoFixUps = 0x100,
-            IgnoreBaseClass = 0x200,
-        }
-
-        public enum AssocStr
-        {
-            Command = 1,
-            Executable,
-            FriendlyDocName,
-            FriendlyAppName,
-            NoOpen,
-            ShellNewValue,
-            DDECommand,
-            DDEIfExec,
-            DDEApplication,
-            DDETopic,
-        }
-
         [DllImport("user32.dll", CharSet = CharSet.Auto, ExactSpelling = true)]
         internal static extern IntPtr GetForegroundWindow();
 
@@ -103,4 +71,150 @@ namespace Peek.UI.Native
         [DllImport("user32.dll")]
         internal static extern int GetWindowText(Windows.Win32.Foundation.HWND hWnd, StringBuilder lpString, int nMaxCount);
     }
+
+    [Flags]
+    public enum AssocF
+    {
+        None = 0,
+        Init_NoRemapCLSID = 0x1,
+        Init_ByExeName = 0x2,
+        Open_ByExeName = 0x2,
+        Init_DefaultToStar = 0x4,
+        Init_DefaultToFolder = 0x8,
+        NoUserSettings = 0x10,
+        NoTruncate = 0x20,
+        Verify = 0x40,
+        RemapRunDll = 0x80,
+        NoFixUps = 0x100,
+        IgnoreBaseClass = 0x200,
+    }
+
+    public enum AssocStr
+    {
+        Command = 1,
+        Executable,
+        FriendlyDocName,
+        FriendlyAppName,
+        NoOpen,
+        ShellNewValue,
+        DDECommand,
+        DDEIfExec,
+        DDEApplication,
+        DDETopic,
+    }
+
+    public enum AccessibleObjectID : uint
+    {
+        OBJID_WINDOW = 0x00000000,
+        OBJID_SYSMENU = 0xFFFFFFFF,
+        OBJID_TITLEBAR = 0xFFFFFFFE,
+        OBJID_MENU = 0xFFFFFFFD,
+        OBJID_CLIENT = 0xFFFFFFFC,
+        OBJID_VSCROLL = 0xFFFFFFFB,
+        OBJID_HSCROLL = 0xFFFFFFFA,
+        OBJID_SIZEGRIP = 0xFFFFFFF9,
+        OBJID_CARET = 0xFFFFFFF8,
+        OBJID_CURSOR = 0xFFFFFFF7,
+        OBJID_ALERT = 0xFFFFFFF6,
+        OBJID_SOUND = 0xFFFFFFF5,
+    }
+
+    public enum WindowEvent : uint
+    {
+        EVENT_MIN = 0x00000001,
+        EVENT_SYSTEM_START = 0x0001,
+        EVENT_SYSTEM_SOUND = 0x0001,
+        EVENT_SYSTEM_ALERT = 0x0002,
+        EVENT_SYSTEM_FOREGROUND = 0x0003,
+        EVENT_SYSTEM_MENUSTART = 0x0004,
+        EVENT_SYSTEM_MENUEND = 0x0005,
+        EVENT_SYSTEM_MENUPOPUPSTART = 0x0006,
+        EVENT_SYSTEM_MENUPOPUPEND = 0x0007,
+        EVENT_SYSTEM_CAPTURESTART = 0x0008,
+        EVENT_SYSTEM_CAPTUREEND = 0x0009,
+        EVENT_SYSTEM_MOVESIZESTART = 0x000A,
+        EVENT_SYSTEM_MOVESIZEEND = 0x000B,
+        EVENT_SYSTEM_CONTEXTHELPSTART = 0x000C,
+        EVENT_SYSTEM_CONTEXTHELPEND = 0x000D,
+        EVENT_SYSTEM_DRAGDROPSTART = 0x000E,
+        EVENT_SYSTEM_DRAGDROPEND = 0x000F,
+        EVENT_SYSTEM_DIALOGSTART = 0x0010,
+        EVENT_SYSTEM_DIALOGEND = 0x0011,
+        EVENT_SYSTEM_SCROLLINGSTART = 0x0012,
+        EVENT_SYSTEM_SCROLLINGEND = 0x0013,
+        EVENT_SYSTEM_SWITCHSTART = 0x0014,
+        EVENT_SYSTEM_SWITCHEND = 0x0015,
+        EVENT_SYSTEM_MINIMIZESTART = 0x0016,
+        EVENT_SYSTEM_MINIMIZEEND = 0x0017,
+        EVENT_SYSTEM_DESKTOPSWITCH = 0x0020,
+        EVENT_SYSTEM_END = 0x00FF,
+        EVENT_OEM_DEFINED_START = 0x0101,
+        EVENT_OEM_DEFINED_END = 0x01FF,
+        EVENT_CONSOLE_START = 0x4001,
+        EVENT_CONSOLE_CARET = 0x4001,
+        EVENT_CONSOLE_UPDATE_REGION = 0x4002,
+        EVENT_CONSOLE_UPDATE_SIMPLE = 0x4003,
+        EVENT_CONSOLE_UPDATE_SCROLL = 0x4004,
+        EVENT_CONSOLE_LAYOUT = 0x4005,
+        EVENT_CONSOLE_START_APPLICATION = 0x4006,
+        EVENT_CONSOLE_END_APPLICATION = 0x4007,
+        EVENT_CONSOLE_END = 0x40FF,
+        EVENT_UIA_EVENTID_START = 0x4E00,
+        EVENT_UIA_EVENTID_END = 0x4EFF,
+        EVENT_UIA_PROPID_START = 0x7500,
+        EVENT_UIA_PROPID_END = 0x75FF,
+        EVENT_OBJECT_START = 0x8000,
+        EVENT_OBJECT_CREATE = 0x8000,
+        EVENT_OBJECT_DESTROY = 0x8001,
+        EVENT_OBJECT_SHOW = 0x8002,
+        EVENT_OBJECT_HIDE = 0x8003,
+        EVENT_OBJECT_REORDER = 0x8004,
+        EVENT_OBJECT_FOCUS = 0x8005,
+        EVENT_OBJECT_SELECTION = 0x8006,
+        EVENT_OBJECT_SELECTIONADD = 0x8007,
+        EVENT_OBJECT_SELECTIONREMOVE = 0x8008,
+        EVENT_OBJECT_SELECTIONWITHIN = 0x8009,
+        EVENT_OBJECT_STATECHANGE = 0x800A,
+        EVENT_OBJECT_LOCATIONCHANGE = 0x800B,
+        EVENT_OBJECT_NAMECHANGE = 0x800C,
+        EVENT_OBJECT_DESCRIPTIONCHANGE = 0x800D,
+        EVENT_OBJECT_VALUECHANGE = 0x800E,
+        EVENT_OBJECT_PARENTCHANGE = 0x800F,
+        EVENT_OBJECT_HELPCHANGE = 0x8010,
+        EVENT_OBJECT_DEFACTIONCHANGE = 0x8011,
+        EVENT_OBJECT_ACCELERATORCHANGE = 0x8012,
+        EVENT_OBJECT_INVOKED = 0x8013,
+        EVENT_OBJECT_TEXTSELECTIONCHANGED = 0x8014,
+        EVENT_OBJECT_CONTENTSCROLLED = 0x8015,
+        EVENT_SYSTEM_ARRANGMENTPREVIEW = 0x8016,
+        EVENT_OBJECT_CLOAKED = 0x8017,
+        EVENT_OBJECT_UNCLOAKED = 0x8018,
+        EVENT_OBJECT_LIVEREGIONCHANGED = 0x8019,
+        EVENT_OBJECT_HOSTEDOBJECTSINVALIDATED = 0x8020,
+        EVENT_OBJECT_DRAGSTART = 0x8021,
+        EVENT_OBJECT_DRAGCANCEL = 0x8022,
+        EVENT_OBJECT_DRAGCOMPLETE = 0x8023,
+        EVENT_OBJECT_DRAGENTER = 0x8024,
+        EVENT_OBJECT_DRAGLEAVE = 0x8025,
+        EVENT_OBJECT_DRAGDROPPED = 0x8026,
+        EVENT_OBJECT_IME_SHOW = 0x8027,
+        EVENT_OBJECT_IME_HIDE = 0x8028,
+        EVENT_OBJECT_IME_CHANGE = 0x8029,
+        EVENT_OBJECT_TEXTEDIT_CONVERSIONTARGETCHANGED = 0x8030,
+        EVENT_OBJECT_END = 0x80FF,
+        EVENT_ATOM_START = 0xC000,
+        EVENT_AIA_START = 0xA000,
+        EVENT_AIA_END = 0xAFFF,
+        EVENT_ATOM_END = 0xFFFF,
+        EVENT_MAX = 0x7FFFFFFF,
+    }
+
+    [Flags]
+    public enum WinEventHookFlags : uint
+    {
+        WINEVENT_OUTOFCONTEXT = 0x0000,
+        WINEVENT_SKIPOWNTHREAD = 0x0001,
+        WINEVENT_SKIPOWNPROCESS = 0x0002,
+        WINEVENT_INCONTEXT = 0x0004,
+    }
 }

src/modules/peek/Peek.UI/NativeMethods.txt

@@ -1,4 +1,6 @@
 MonitorFromWindow
 GetMonitorInfo
 GetDpiForWindow
-GetWindowTextLength
+GetWindowTextLength
+SetWinEventHook
+UnhookWinEvent

src/modules/peek/Peek.UI/Window/WindowEventHook.cs

@@ -0,0 +1,56 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Peek.UI.WindowEventHook
+{
+    using System;
+    using System.Reflection.Metadata;
+    using System.Runtime.ConstrainedExecution;
+    using System.Runtime.InteropServices;
+    using Microsoft.Win32.SafeHandles;
+    using Peek.UI.Native;
+    using Windows.Win32;
+
+    public class WindowEventHook : IDisposable
+    {
+        public event EventHandler<WindowEventHookEventArgs>? WindowEventReceived;
+
+        public WindowEventHook()
+        {
+            var moveOrResizeEvent = WindowEvent.EVENT_SYSTEM_MOVESIZEEND;
+
+            var windowHookEventHandler = new WindowEventProc(OnWindowEventProc);
+
+            var hook = PInvoke.SetWinEventHook(
+                (uint)moveOrResizeEvent,
+                (uint)moveOrResizeEvent,
+                new SafeHandle(),
+                windowHookEventHandler,
+                0,
+                0,
+                WinEventHookFlags.WINEVENT_OUTOFCONTEXT | WinEventHookFlags.WINEVENT_SKIPOWNPROCESS);
+        }
+
+        public void Dispose()
+        {
+            throw new NotImplementedException();
+        }
+
+        private void OnWindowEventProc(nint hWinEventHook, WindowEvent eventType, nint hwnd, AccessibleObjectID idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
+        {
+            throw new NotImplementedException();
+        }
+    }
+
+    public record WindowEventHookEventArgs(WindowEvent eventType, IntPtr windowHandle);
+
+    public delegate void WindowEventProc(
+        IntPtr hWinEventHook,
+        WindowEvent eventType,
+        IntPtr hwnd,
+        AccessibleObjectID idObject,
+        int idChild,
+        uint dwEventThread,
+        uint dwmsEventTime);
+}

src/modules/peek/Peek.UI/Window/WindowEventSafeHandle.cs

@@ -0,0 +1,32 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Peek.UI.WindowEventHook
+{
+    using System;
+    using System.Runtime.ConstrainedExecution;
+    using Microsoft.Win32.SafeHandles;
+    using Peek.UI.Native;
+
+    public class WindowEventSafeHandle : SafeHandleZeroOrMinusOneIsInvalid
+    {
+        private WindowEventSafeHandle(IntPtr handle)
+            : base(true)
+        {
+            SetHandle(handle);
+        }
+
+        public WindowEventSafeHandle()
+            : base(true)
+        {
+            SetHandle(handle);
+        }
+
+        protected override bool ReleaseHandle()
+        {
+            NativeMethods.DeleteObject(this);
+            return true;
+        }
+    }
+}