Resolving warnings and treating warnings as errors in WinUI project. (#824)

Wino.Mail.WinUI/Services/ApplicationResourceManager.cs

@@ -16,7 +16,7 @@ public class ApplicationResourceManager : IApplicationResourceManager<ResourceDi
         => WinoApplication.Current.Resources.ContainsKey(resourceKey);
 
     public ResourceDictionary GetLastResource()
-        => WinoApplication.Current.Resources.MergedDictionaries.LastOrDefault();
+        => WinoApplication.Current.Resources.MergedDictionaries.LastOrDefault()!;
 
     public void ReplaceResource(string resourceKey, object resource)
         => WinoApplication.Current.Resources[resourceKey] = resource;

Wino.Mail.WinUI/Services/ConfigurationService.cs

@@ -9,10 +9,10 @@ namespace Wino.Mail.WinUI.Services;
 
 public class ConfigurationService : IConfigurationService
 {
-    public T Get<T>(string key, T defaultValue = default)
+    public T Get<T>(string key, T defaultValue = default!)
         => GetInternal(key, ApplicationData.Current.LocalSettings.Values, defaultValue);
 
-    public T GetRoaming<T>(string key, T defaultValue = default)
+    public T GetRoaming<T>(string key, T defaultValue = default!)
         => GetInternal(key, ApplicationData.Current.RoamingSettings.Values, defaultValue);
 
     public void Set(string key, object value)
@@ -21,11 +21,13 @@ public class ConfigurationService : IConfigurationService
     public void SetRoaming(string key, object value)
         => SetInternal(key, value, ApplicationData.Current.RoamingSettings.Values);
 
-    private static T GetInternal<T>(string key, IPropertySet collection, T defaultValue = default)
+    private static T GetInternal<T>(string key, IPropertySet collection, T defaultValue = default!)
     {
-        if (collection.TryGetValue(key, out object value))
+        if (collection.TryGetValue(key, out object? value))
         {
             var stringValue = value?.ToString();
+            if (string.IsNullOrWhiteSpace(stringValue))
+                return defaultValue;
 
             if (typeof(T).IsEnum)
                 return (T)Enum.Parse(typeof(T), stringValue);
@@ -40,7 +42,8 @@ public class ConfigurationService : IConfigurationService
                 return (T)(object)TimeSpan.Parse(stringValue);
             }
 
-            return (T)Convert.ChangeType(stringValue, typeof(T));
+            var converted = Convert.ChangeType(stringValue, typeof(T));
+            return converted is T typed ? typed : defaultValue;
         }
 
         return defaultValue;

Wino.Mail.WinUI/Services/DialogService.cs

@@ -119,7 +119,7 @@ public class DialogService : DialogServiceBase, IMailDialogService
 
         await HandleDialogPresentationAsync(accountPicker);
 
-        return accountPicker.PickedAccount;
+        return accountPicker.PickedAccount ?? null!;
     }
 
     public async Task<AccountSignature> ShowSignatureEditorDialog(AccountSignature? signatureModel = null)

Wino.Mail.WinUI/Services/DialogServiceBase.cs

@@ -40,7 +40,7 @@ public class DialogServiceBase : IDialogServiceBase
         ApplicationResourceManager = applicationResourceManager;
     }
 
-    protected XamlRoot GetXamlRoot()
+    protected XamlRoot? GetXamlRoot()
     {
         return WinoApplication.MainWindow?.Content?.XamlRoot;
     }
@@ -54,7 +54,10 @@ public class DialogServiceBase : IDialogServiceBase
 
         picker.FileTypeFilter.Add("*");
 
-        nint windowHandle = WindowNative.GetWindowHandle(WinoApplication.MainWindow);
+        var mainWindow = WinoApplication.MainWindow;
+        if (mainWindow == null) return string.Empty;
+
+        nint windowHandle = WindowNative.GetWindowHandle(mainWindow);
         InitializeWithWindow.Initialize(picker, windowHandle);
 
         var folder = await picker.PickSingleFolderAsync();
@@ -94,7 +97,10 @@ public class DialogServiceBase : IDialogServiceBase
             picker.FileTypeFilter.Add(filter.ToString());
         }
 
-        nint windowHandle = WindowNative.GetWindowHandle(WinoApplication.MainWindow);
+        var mainWindow = WinoApplication.MainWindow;
+        if (mainWindow == null) return returnList;
+
+        nint windowHandle = WindowNative.GetWindowHandle(mainWindow);
         InitializeWithWindow.Initialize(picker, windowHandle);
 
         var files = await picker.PickMultipleFilesAsync();
@@ -111,7 +117,7 @@ public class DialogServiceBase : IDialogServiceBase
         return returnList;
     }
 
-    private async Task<StorageFile> PickFileAsync(params object[] typeFilters)
+    private async Task<StorageFile?> PickFileAsync(params object[] typeFilters)
     {
         var picker = new FileOpenPicker
         {
@@ -123,7 +129,10 @@ public class DialogServiceBase : IDialogServiceBase
             picker.FileTypeFilter.Add(filter.ToString());
         }
 
-        nint windowHandle = WindowNative.GetWindowHandle(WinoApplication.MainWindow);
+        var mainWindow = WinoApplication.MainWindow;
+        if (mainWindow == null) return null;
+
+        nint windowHandle = WindowNative.GetWindowHandle(mainWindow);
         InitializeWithWindow.Initialize(picker, windowHandle);
 
         var file = await picker.PickSingleFileAsync();
@@ -174,7 +183,7 @@ public class DialogServiceBase : IDialogServiceBase
 
         if (isDontAskEnabled && ConfigurationService.Get(dontAskAgainConfigurationKey, false)) return false;
 
-        var informationContainer = new CustomMessageDialogInformationContainer(title, description, icon.Value, isDontAskEnabled);
+        var informationContainer = new CustomMessageDialogInformationContainer(title, description, icon ?? WinoCustomMessageDialogIcon.Information, isDontAskEnabled);
 
         var dialog = new ContentDialog
         {
@@ -270,7 +279,10 @@ public class DialogServiceBase : IDialogServiceBase
 
         picker.FileTypeFilter.Add("*");
 
-        nint windowHandle = WindowNative.GetWindowHandle(WinoApplication.MainWindow);
+        var mainWindow = WinoApplication.MainWindow;
+        if (mainWindow == null) return string.Empty;
+
+        nint windowHandle = WindowNative.GetWindowHandle(mainWindow);
         InitializeWithWindow.Initialize(picker, windowHandle);
 
         var pickedFolder = await picker.PickSingleFolderAsync();
@@ -307,10 +319,10 @@ public class DialogServiceBase : IDialogServiceBase
 
         await HandleDialogPresentationAsync(dialog);
 
-        return dialog.Result;
+        return dialog.Result ?? null!;
     }
 
-    public async Task<WebView2PrintSettingsModel> ShowPrintDialogAsync(WebView2PrintSettingsModel initialSettings = null)
+    public async Task<WebView2PrintSettingsModel> ShowPrintDialogAsync(WebView2PrintSettingsModel initialSettings = default!)
     {
         try
         {
@@ -334,13 +346,13 @@ public class DialogServiceBase : IDialogServiceBase
             // Return the settings if user clicked Print, otherwise null
             return result == ContentDialogResult.Primary
                 ? dialog.PrintSettings
-                : null;
+                : null!;
         }
         catch (Exception ex)
         {
             // Log the exception if logging is available
             Log.Error(ex, "Error showing print dialog");
-            return null;
+            return null!;
         }
     }
 }

Wino.Mail.WinUI/Services/NativeAppService.cs

@@ -16,10 +16,10 @@ namespace Wino.Services;
 
 public class NativeAppService : INativeAppService
 {
-    private string _mimeMessagesFolder;
-    private string _editorBundlePath;
+    private string _mimeMessagesFolder = string.Empty;
+    private string _editorBundlePath = string.Empty;
 
-    public Func<IntPtr> GetCoreWindowHwnd { get; set; }
+    public Func<IntPtr> GetCoreWindowHwnd { get; set; } = static () => IntPtr.Zero;
 
     public string GetWebAuthenticationBrokerUri()
     {

Wino.Mail.WinUI/Services/NavigationService.cs

@@ -100,7 +100,10 @@ public class NavigationService : NavigationServiceBase, INavigationService
 
         if (frameType == NavigationReferenceFrame.ShellFrame) return shellWindow.GetMainFrame();
 
-        return WinoVisualTreeHelper.GetChildObject<Frame>(mainFrame.Content as UIElement, frameType.ToString());
+        var contentRoot = mainFrame.Content as UIElement;
+        if (contentRoot == null) return mainFrame;
+
+        return WinoVisualTreeHelper.GetChildObject<Frame>(contentRoot, frameType.ToString()) ?? mainFrame;
     }
 
     public bool ChangeApplicationMode(WinoApplicationMode mode)

Wino.Mail.WinUI/Services/NavigationServiceBase.cs

@@ -17,7 +17,7 @@ public class NavigationServiceBase
         };
     }
 
-    public Type GetCurrentFrameType(ref Frame _frame)
+    public Type? GetCurrentFrameType(ref Frame _frame)
     {
         if (_frame != null && _frame.Content != null)
             return _frame.Content.GetType();

Wino.Mail.WinUI/Services/NewThemeService.cs

@@ -45,9 +45,9 @@ public class NewThemeService : INewThemeService
     private static string _snowflakeThemeId = "e143ddde-2e28-4846-9d98-dad63d6505f1";
     private static string _gardenThemeId = "698e4466-f88c-4799-9c61-f0ea1308ed49";
 
-    public event EventHandler<ApplicationElementTheme> ElementThemeChanged;
-    public event EventHandler<string> AccentColorChanged;
-    public event EventHandler<WindowBackdropType> BackdropChanged;
+    public event EventHandler<ApplicationElementTheme>? ElementThemeChanged;
+    public event EventHandler<string>? AccentColorChanged;
+    public event EventHandler<WindowBackdropType>? BackdropChanged;
 
     private const string AccentColorKey = nameof(AccentColorKey);
     private const string CurrentApplicationThemeKey = nameof(CurrentApplicationThemeKey);
@@ -125,7 +125,7 @@ public class NewThemeService : INewThemeService
         }
     }
 
-    private string accentColor;
+    private string accentColor = string.Empty;
 
     public string AccentColor
     {
@@ -218,7 +218,7 @@ public class NewThemeService : INewThemeService
 
         try
         {
-            Microsoft.UI.Xaml.Media.SystemBackdrop backdrop = backdropType switch
+            Microsoft.UI.Xaml.Media.SystemBackdrop? backdrop = backdropType switch
             {
                 WindowBackdropType.Mica => new MicaBackdrop() { Kind = Microsoft.UI.Composition.SystemBackdrops.MicaKind.Base },
                 WindowBackdropType.MicaAlt => new MicaBackdrop() { Kind = Microsoft.UI.Composition.SystemBackdrops.MicaKind.BaseAlt },
@@ -385,7 +385,7 @@ public class NewThemeService : INewThemeService
             return;
         }
 
-        AppThemeBase applyingTheme = null;
+        AppThemeBase? applyingTheme = null;
 
         var controlThemeList = new List<AppThemeBase>(preDefinedThemes);
 
@@ -416,13 +416,19 @@ public class NewThemeService : INewThemeService
             }
         }
 
+        if (applyingTheme == null)
+        {
+            Debug.WriteLine($"Theme with ID {currentApplicationThemeId} not found, skipping theme application");
+            return;
+        }
+
         try
         {
             var existingThemeDictionary = _applicationResourceManager.GetLastResource();
 
-            if (existingThemeDictionary != null && existingThemeDictionary.TryGetValue("ThemeName", out object themeNameString))
+            if (existingThemeDictionary != null && existingThemeDictionary.TryGetValue("ThemeName", out object? themeNameString))
             {
-                var themeName = themeNameString.ToString();
+                var themeName = themeNameString?.ToString();
 
                 // Applying different theme.
                 if (themeName != applyingTheme.ThemeName)
@@ -430,6 +436,10 @@ public class NewThemeService : INewThemeService
                     var resourceDictionaryContent = await applyingTheme.GetThemeResourceDictionaryContentAsync();
 
                     var resourceDictionary = XamlReader.Load(resourceDictionaryContent) as ResourceDictionary;
+                    if (resourceDictionary == null)
+                    {
+                        return;
+                    }
 
                     // Custom themes require special attention for background image because 
                     // they share the same base theme resource dictionary.
@@ -561,7 +571,7 @@ public class NewThemeService : INewThemeService
         return results;
     }
 
-    private async Task<CustomThemeMetadata> GetCustomMetadataAsync(IStorageFile file)
+    private async Task<CustomThemeMetadata?> GetCustomMetadataAsync(IStorageFile file)
     {
         var fileContent = await FileIO.ReadTextAsync(file);
 

Wino.Mail.WinUI/Services/NotificationBuilder.cs

@@ -215,7 +215,12 @@ public class NotificationBuilder : INotificationBuilder
                 XmlDocument badgeXml = BadgeUpdateManager.GetTemplateContent(BadgeTemplateType.BadgeNumber);
 
                 // Set the value of the badge in the XML to our number
-                XmlElement badgeElement = badgeXml.SelectSingleNode("/badge") as XmlElement;
+                XmlElement? badgeElement = badgeXml.SelectSingleNode("/badge") as XmlElement;
+                if (badgeElement == null)
+                {
+                    badgeUpdater.Clear();
+                    return;
+                }
                 badgeElement.SetAttribute("value", totalUnreadCount.ToString());
 
                 // Create the badge notification

Wino.Mail.WinUI/Services/PreferencesService.cs

@@ -17,20 +17,20 @@ public class PreferencesService(IConfigurationService configurationService) : Ob
 {
     private readonly IConfigurationService _configurationService = configurationService;
 
-    public event EventHandler<string> PreferenceChanged;
+    public event EventHandler<string>? PreferenceChanged;
 
     protected override void OnPropertyChanged(PropertyChangedEventArgs e)
     {
         base.OnPropertyChanged(e);
 
-        PreferenceChanged?.Invoke(this, e.PropertyName);
+        PreferenceChanged?.Invoke(this, e.PropertyName ?? string.Empty);
     }
 
-    private void SaveProperty(string propertyName, object value) => _configurationService.Set(propertyName, value);
+    private void SaveProperty(string propertyName, object? value) => _configurationService.Set(propertyName, value ?? string.Empty);
 
-    private void SetPropertyAndSave(string propertyName, object value)
+    private void SetPropertyAndSave(string propertyName, object? value)
     {
-        _configurationService.Set(propertyName, value);
+        _configurationService.Set(propertyName, value ?? string.Empty);
 
         OnPropertyChanged(propertyName);
         Debug.WriteLine($"PreferencesService -> {propertyName}:{value?.ToString()}");

Wino.Mail.WinUI/Services/PrintService.cs

@@ -24,10 +24,10 @@ namespace Wino.Mail.WinUI.Services;
 
 public class PrintService : IPrintService
 {
-    private TaskCompletionSource<PrintingResult> _taskCompletionSource;
-    private CanvasPrintDocument printDocument;
-    private PrintTask printTask;
-    private PdfDocument pdfDocument;
+    private TaskCompletionSource<PrintingResult>? _taskCompletionSource;
+    private CanvasPrintDocument? printDocument;
+    private PrintTask? printTask;
+    private PdfDocument? pdfDocument;
 
     private List<CanvasBitmap> bitmaps = new();
     private Vector2 largestBitmap;
@@ -41,7 +41,7 @@ public class PrintService : IPrintService
     private int bitmapsPerPage;
     private int pageCount = -1;
 
-    private PrintInformation _currentPrintInformation;
+    private PrintInformation? _currentPrintInformation;
 
     public async Task<PrintingResult> PrintPdfFileAsync(string pdfFilePath, string printTitle)
     {
@@ -125,6 +125,9 @@ public class PrintService : IPrintService
 
         printTask = args.Request.CreatePrintTask(_currentPrintInformation.PDFTitle, (createPrintTaskArgs) =>
         {
+            if (printDocument == null)
+                return;
+
             createPrintTaskArgs.SetSource(printDocument);
         });
 
@@ -191,6 +194,9 @@ public class PrintService : IPrintService
 
     private async Task LoadPDFPageBitmapsAsync(CanvasPrintDocument sender)
     {
+        if (pdfDocument == null)
+            return;
+
         ClearBitmaps();
 
         bitmaps ??= new List<CanvasBitmap>();
@@ -226,6 +232,9 @@ public class PrintService : IPrintService
     {
         var detailedOptions = PrintTaskOptionDetails.GetFromPrintTaskOptions(args.PrintTaskOptions);
 
+        if (pdfDocument == null)
+            return;
+
         int pageCountToPrint = (int)pdfDocument.PageCount;
 
         for (uint i = 1; i <= pageCountToPrint; ++i)
@@ -239,7 +248,7 @@ public class PrintService : IPrintService
 
     private void DrawPdfPage(CanvasPrintDocument sender, CanvasDrawingSession ds, uint pageNumber)
     {
-        if (bitmaps?.Count == 0) return;
+        if (bitmaps.Count == 0) return;
 
         var cellAcross = new Vector2(cellSize.X, 0);
         var cellDown = new Vector2(0, cellSize.Y);

Wino.Mail.WinUI/Services/SmimeCertificateService.cs

@@ -17,7 +17,7 @@ public class SmimeCertificateService : ISmimeCertificateService
     /// private key and at least one extension. The store is opened in read-only mode.</remarks>
     /// <returns>An enumerable collection of <see cref="X509Certificate2"/> objects representing the personal certificates that
     /// meet the specified criteria. If no matching certificates are found, the collection will be empty.</returns>
-    public IEnumerable<X509Certificate2> GetCertificates(StoreName storeName = StoreName.My, StoreLocation storeLocation = StoreLocation.CurrentUser, string emailAddress = null)
+    public IEnumerable<X509Certificate2> GetCertificates(StoreName storeName = StoreName.My, StoreLocation storeLocation = StoreLocation.CurrentUser, string? emailAddress = null)
     {
         using var store = new X509Store(storeName, storeLocation);
         store.Open(OpenFlags.ReadOnly);
@@ -26,7 +26,7 @@ public class SmimeCertificateService : ISmimeCertificateService
     }
 
 
-    public void ImportCertificate(string fileExtension, byte[] rawData, string password = null, StoreName storeName = StoreName.My, StoreLocation storeLocation = StoreLocation.CurrentUser)
+    public void ImportCertificate(string fileExtension, byte[] rawData, string? password = null, StoreName storeName = StoreName.My, StoreLocation storeLocation = StoreLocation.CurrentUser)
     {
         X509Certificate2Collection collection = [];
 

Wino.Mail.WinUI/Services/StatePersistenceService.cs

@@ -198,7 +198,13 @@ public class StatePersistenceService : ObservableObject, IStatePersistanceServic
         }
     }
 
-    private void UpdateAppCoreWindowTitle() => WinoApplication.MainWindow.Title = CoreWindowTitle;
+    private void UpdateAppCoreWindowTitle()
+    {
+        if (WinoApplication.MainWindow != null)
+        {
+            WinoApplication.MainWindow.Title = CoreWindowTitle;
+        }
+    }
 
     private static CalendarDisplayType EnsureValidCalendarDisplayType(CalendarDisplayType displayType)
     {

Wino.Mail.WinUI/Services/ThumbnailService.cs

@@ -21,7 +21,7 @@ public class ThumbnailService(IPreferencesService preferencesService, IDatabaseS
     private static readonly HttpClient _httpClient = new();
     private bool _isInitialized = false;
 
-    private ConcurrentDictionary<string, (string graviton, string favicon)> _cache;
+    private ConcurrentDictionary<string, (string? graviton, string? favicon)> _cache = [];
     private readonly ConcurrentDictionary<string, Task> _requests = [];
 
     private static readonly List<string> _excludedFaviconDomains = [
@@ -43,7 +43,7 @@ public class ThumbnailService(IPreferencesService preferencesService, IDatabaseS
         "rediffmail.com"
         ];
 
-    public async ValueTask<string> GetThumbnailAsync(string email, bool awaitLoad = false)
+    public async ValueTask<string?> GetThumbnailAsync(string email, bool awaitLoad = false)
     {
         if (string.IsNullOrWhiteSpace(email))
             return null;
@@ -55,8 +55,8 @@ public class ThumbnailService(IPreferencesService preferencesService, IDatabaseS
         {
             var thumbnailsList = await _databaseService.Connection.Table<Thumbnail>().ToListAsync();
 
-            _cache = new ConcurrentDictionary<string, (string graviton, string favicon)>(
-                thumbnailsList.ToDictionary(x => x.Domain, x => (x.Gravatar, x.Favicon)));
+            _cache = new ConcurrentDictionary<string, (string? graviton, string? favicon)>(
+                thumbnailsList.ToDictionary(x => x.Domain, x => ((string?)x.Gravatar, (string?)x.Favicon)));
             _isInitialized = true;
         }
 
@@ -84,7 +84,7 @@ public class ThumbnailService(IPreferencesService preferencesService, IDatabaseS
         await _databaseService.Connection.DeleteAllAsync<Thumbnail>();
     }
 
-    private async ValueTask<(string gravatar, string favicon)> GetThumbnailInternal(string email, bool awaitLoad)
+    private async ValueTask<(string? gravatar, string? favicon)> GetThumbnailInternal(string email, bool awaitLoad)
     {
         if (_cache.TryGetValue(email, out var cached))
             return cached;
@@ -136,7 +136,7 @@ public class ThumbnailService(IPreferencesService preferencesService, IDatabaseS
         WeakReferenceMessenger.Default.Send(new ThumbnailAdded(email));
     }
 
-    private static async Task<string> GetGravatarBase64(string email)
+    private static async Task<string?> GetGravatarBase64(string email)
     {
         try
         {
@@ -156,7 +156,7 @@ public class ThumbnailService(IPreferencesService preferencesService, IDatabaseS
         return null;
     }
 
-    private static async Task<string> GetFaviconBase64(string email)
+    private static async Task<string?> GetFaviconBase64(string email)
     {
         try
         {