Main app aot compatibility.

.editorconfig

@@ -8,6 +8,9 @@ dotnet_style_operator_placement_when_wrapping = beginning_of_line
 tab_width = 4
 indent_size = 4
 end_of_line = crlf
+[XamlTypeInfo.g.cs]
+dotnet_diagnostic.CS0612.severity = none
+dotnet_diagnostic.CS0618.severity = none
 dotnet_style_coalesce_expression = true:suggestion
 dotnet_style_null_propagation = true:suggestion
 dotnet_style_prefer_is_null_check_over_reference_equality_method = true:suggestion

Wino.Mail.WinUI/Activation/DefaultActivationHandler.cs

@@ -1,22 +0,0 @@
-using System.Threading.Tasks;
-using Windows.ApplicationModel.Activation;
-using Microsoft.UI.Xaml;
-using Microsoft.UI.Xaml.Controls;
-using Microsoft.UI.Xaml.Media.Animation;
-using Wino.Views;
-
-namespace Wino.Activation;
-
-internal class DefaultActivationHandler : ActivationHandler<IActivatedEventArgs>
-{
-    protected override Task HandleInternalAsync(IActivatedEventArgs args)
-    {
-        (Window.Current.Content as Frame).Navigate(typeof(AppShell), null, new DrillInNavigationTransitionInfo());
-
-        return Task.CompletedTask;
-    }
-
-    // Only navigate if Frame content doesn't exist.
-    protected override bool CanHandleInternal(IActivatedEventArgs args)
-        => (Window.Current?.Content as Frame)?.Content == null;
-}

Wino.Mail.WinUI/Activation/FileActivationHandler.cs

@@ -1,67 +0,0 @@
-using System;
-using System.IO;
-using System.Linq;
-using System.Threading.Tasks;
-using Windows.ApplicationModel.Activation;
-using Windows.Storage;
-using Microsoft.UI.Xaml;
-using Microsoft.UI.Xaml.Controls;
-using Microsoft.UI.Xaml.Media.Animation;
-using Wino.Core.Domain.Enums;
-using Wino.Core.Domain.Interfaces;
-using Wino.Core.WinUI.Extensions;
-using Wino.Views;
-
-namespace Wino.Activation;
-
-internal class FileActivationHandler : ActivationHandler<FileActivatedEventArgs>
-{
-    private readonly INativeAppService _nativeAppService;
-    private readonly IMimeFileService _mimeFileService;
-    private readonly IStatePersistanceService _statePersistanceService;
-    private readonly INavigationService _winoNavigationService;
-
-    public FileActivationHandler(INativeAppService nativeAppService,
-                                 IMimeFileService mimeFileService,
-                                 IStatePersistanceService statePersistanceService,
-                                 INavigationService winoNavigationService)
-    {
-        _nativeAppService = nativeAppService;
-        _mimeFileService = mimeFileService;
-        _statePersistanceService = statePersistanceService;
-        _winoNavigationService = winoNavigationService;
-    }
-
-    protected override async Task HandleInternalAsync(FileActivatedEventArgs args)
-    {
-        // Always handle the last item passed.
-        // Multiple files are not supported.
-
-        var file = args.Files.Last() as StorageFile;
-
-        // Only EML files are supported now.
-        var fileExtension = Path.GetExtension(file.Path);
-
-        if (string.Equals(fileExtension, ".eml", StringComparison.OrdinalIgnoreCase))
-        {
-            var fileBytes = await file.ToByteArrayAsync();
-            var directoryName = Path.GetDirectoryName(file.Path);
-
-            var messageInformation = await _mimeFileService.GetMimeMessageInformationAsync(fileBytes, directoryName).ConfigureAwait(false);
-
-            if (_nativeAppService.IsAppRunning())
-            {
-                // TODO: Activate another Window and go to mail rendering page.
-                _winoNavigationService.Navigate(WinoPage.MailRenderingPage, messageInformation, NavigationReferenceFrame.RenderingFrame);
-            }
-            else
-            {
-                _statePersistanceService.ShouldShiftMailRenderingDesign = true;
-                (Window.Current.Content as Frame).Navigate(typeof(MailRenderingPage), messageInformation, new DrillInNavigationTransitionInfo());
-            }
-        }
-    }
-
-    protected override bool CanHandleInternal(FileActivatedEventArgs args) => args.Files.Any();
-
-}

Wino.Mail.WinUI/Activation/ToastNotificationActivationHandler.cs

@@ -1,76 +0,0 @@
-using System;
-using System.Threading.Tasks;
-using CommunityToolkit.Mvvm.Messaging;
-using Microsoft.Extensions.DependencyInjection;
-using Microsoft.Toolkit.Uwp.Notifications;
-using Serilog;
-using Windows.ApplicationModel.Activation;
-using Wino.Core.Domain;
-using Wino.Core.Domain.Interfaces;
-using Wino.Mail.WinUI;
-using Wino.Messaging.Client.Accounts;
-
-namespace Wino.Activation;
-
-/// <summary>
-/// This handler will only handle the toasts that runs on foreground.
-/// Background executions are not handled here like mark as read or delete.
-/// </summary>
-internal class ToastNotificationActivationHandler : ActivationHandler<ToastNotificationActivatedEventArgs>
-{
-    private readonly IMailService _mailService;
-    private readonly IFolderService _folderService;
-
-    private ToastArguments _toastArguments;
-
-    public ToastNotificationActivationHandler(IMailService mailService,
-                                              IFolderService folderService)
-    {
-        _mailService = mailService;
-        _folderService = folderService;
-    }
-
-    protected override async Task HandleInternalAsync(ToastNotificationActivatedEventArgs args)
-    {
-        // Create the mail item navigation event.
-        // If the app is running, it'll be picked up by the Messenger.
-        // Otherwise we'll save it and handle it when the shell loads all accounts.
-
-        // Parse the mail unique id and perform above actions.
-        if (Guid.TryParse(_toastArguments[Constants.ToastMailUniqueIdKey], out Guid mailItemUniqueId))
-        {
-            var account = await _mailService.GetMailAccountByUniqueIdAsync(mailItemUniqueId).ConfigureAwait(false);
-            if (account == null) return;
-
-            var mailItem = await _mailService.GetSingleMailItemAsync(mailItemUniqueId).ConfigureAwait(false);
-            if (mailItem == null) return;
-
-            var message = new AccountMenuItemExtended(mailItem.AssignedFolder.Id, mailItem);
-
-            // Delegate this event to LaunchProtocolService so app shell can pick it up on launch if app doesn't work.
-            var launchProtocolService = App.Current.Services.GetRequiredService<ILaunchProtocolService>();
-            launchProtocolService.LaunchParameter = message;
-
-            // Send the messsage anyways. Launch protocol service will be ignored if the message is picked up by subscriber shell.
-            WeakReferenceMessenger.Default.Send(message);
-        }
-    }
-
-    protected override bool CanHandleInternal(ToastNotificationActivatedEventArgs args)
-    {
-        try
-        {
-            _toastArguments = ToastArguments.Parse(args.Argument);
-
-            return
-                _toastArguments.Contains(Constants.ToastMailUniqueIdKey) &&
-                _toastArguments.Contains(Constants.ToastActionKey);
-        }
-        catch (Exception ex)
-        {
-            Log.Error(ex, "Couldn't handle parsing toast notification arguments for foreground navigate.");
-        }
-
-        return false;
-    }
-}

Wino.Mail.WinUI/AppShell.xaml.cs

@@ -75,6 +75,9 @@ public sealed partial class AppShell : AppShellAbstract,
                     var mailCopies = new List<MailCopy>();
 
                     var dragPackage = e.DataView.Properties[nameof(MailDragPackage)] as MailDragPackage;
+
+                    if (dragPackage == null) return;
+
                     e.AcceptedOperation = Windows.ApplicationModel.DataTransfer.DataPackageOperation.Move;
 
                     // Extract mail copies from IMailItem.
@@ -116,7 +119,7 @@ public sealed partial class AppShell : AppShellAbstract,
         var dragPackage = args.DataView.Properties[nameof(MailDragPackage)] as MailDragPackage;
 
         // Invalid package.
-        if (!dragPackage.DraggingMails.Any()) return false;
+        if (dragPackage == null || !dragPackage.DraggingMails.Any()) return false;
 
         // Check whether source and target folder are the same.
         if (interactingContainer.IsSelected) return false;
@@ -144,6 +147,8 @@ public sealed partial class AppShell : AppShellAbstract,
 
             var draggingFolder = droppedContainer.DataContext as IBaseFolderMenuItem;
 
+            if (draggingFolder == null) return;
+
             e.AcceptedOperation = Windows.ApplicationModel.DataTransfer.DataPackageOperation.Move;
             e.DragUIOverride.Caption = string.Format(Translator.DragMoveToFolderCaption, draggingFolder.FolderName);
         }
@@ -235,7 +240,7 @@ public sealed partial class AppShell : AppShellAbstract,
 
     private void ShellFrameContentNavigated(object sender, Microsoft.UI.Xaml.Navigation.NavigationEventArgs e) => TopShellContent = ((BasePage)e.Content).ShellContent;
 
-    partial void OnTopShellContentChanged(UIElement newValue) => WeakReferenceMessenger.Default.Send(new TitleBarShellContentUpdated());
+    partial void OnTopShellContentChanged(UIElement? newValue) => WeakReferenceMessenger.Default.Send(new TitleBarShellContentUpdated());
 
     private async void MenuItemContextRequested(UIElement sender, ContextRequestedEventArgs args)
     {

Wino.Mail.WinUI/Behaviors/BindableCommandBarBehavior.cs

@@ -17,13 +17,13 @@ namespace Wino.Behaviors;
 
 public partial class BindableCommandBarBehavior : Behavior<CommandBar>
 {
-    private readonly IPreferencesService _preferencesService = App.Current.Services.GetService<IPreferencesService>();
+    private readonly IPreferencesService? _preferencesService = App.Current.Services.GetService<IPreferencesService>();
     public static readonly DependencyProperty PrimaryCommandsProperty = DependencyProperty.Register(
         "PrimaryCommands", typeof(object), typeof(BindableCommandBarBehavior),
         new PropertyMetadata(null, UpdateCommands));
 
     [GeneratedDependencyProperty]
-    public partial ICommand ItemClickedCommand { get; set; }
+    public partial ICommand? ItemClickedCommand { get; set; }
 
     public object PrimaryCommands
     {
@@ -88,7 +88,7 @@ public partial class BindableCommandBarBehavior : Behavior<CommandBar>
         {
             if (command is MailOperationMenuItem mailOperationMenuItem)
             {
-                ICommandBarElement menuItem = null;
+                ICommandBarElement? menuItem = null;
 
                 if (mailOperationMenuItem.Operation == Core.Domain.Enums.MailOperation.Seperator)
                 {
@@ -97,13 +97,17 @@ public partial class BindableCommandBarBehavior : Behavior<CommandBar>
                 else
                 {
                     var label = XamlHelpers.GetOperationString(mailOperationMenuItem.Operation);
-                    var labelPosition = string.IsNullOrWhiteSpace(label) || !_preferencesService.IsShowActionLabelsEnabled ?
+                    var labelPosition = string.IsNullOrWhiteSpace(label) || _preferencesService == null || !_preferencesService.IsShowActionLabelsEnabled ?
                         CommandBarLabelPosition.Collapsed : CommandBarLabelPosition.Default;
+
+                    var iconGlyph = XamlHelpers.GetWinoIconGlyph(mailOperationMenuItem.Operation);
+                    var glyphValue = ControlConstants.WinoIconFontDictionary.TryGetValue(iconGlyph, out var glyph) ? glyph : string.Empty;
+
                     menuItem = new AppBarButton
                     {
                         Width = double.NaN,
                         MinWidth = 40,
-                        Icon = new WinoFontIcon() { Glyph = ControlConstants.WinoIconFontDictionary[XamlHelpers.GetWinoIconGlyph(mailOperationMenuItem.Operation)] },
+                        Icon = new WinoFontIcon() { Glyph = glyphValue },
                         Label = label,
                         LabelPosition = labelPosition,
                         DataContext = mailOperationMenuItem,
@@ -162,7 +166,7 @@ public partial class BindableCommandBarBehavior : Behavior<CommandBar>
         UpdatePrimaryCommands();
     }
 
-    private void PrimaryCommandsCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
+    private void PrimaryCommandsCollectionChanged(object? sender, NotifyCollectionChangedEventArgs e)
     {
         UpdatePrimaryCommands();
     }

Wino.Mail.WinUI/Behaviors/CreateMailNavigationItemBehavior.cs

@@ -58,7 +58,7 @@ public class CreateMailNavigationItemBehavior : Behavior<WinoNavigationViewItem>
         }
     }
 
-    private void MenuCollectionUpdated(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
+    private void MenuCollectionUpdated(object? sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
     {
         ManageAccounts();
     }

Wino.Mail.WinUI/Controls/AccountNavigationItem.cs

@@ -28,8 +28,8 @@ public partial class AccountNavigationItem : WinoNavigationViewItem
     private const string PART_NavigationViewItemMenuItemsHost = "NavigationViewItemMenuItemsHost";
     private const string PART_SelectionIndicator = "CustomSelectionIndicator";
 
-    private ItemsRepeater _itemsRepeater;
+    private ItemsRepeater _itemsRepeater = null!;
-    private Microsoft.UI.Xaml.Shapes.Rectangle _selectionIndicator;
+    private Microsoft.UI.Xaml.Shapes.Rectangle _selectionIndicator = null!;
 
     public AccountNavigationItem()
     {
@@ -40,8 +40,8 @@ public partial class AccountNavigationItem : WinoNavigationViewItem
     {
         base.OnApplyTemplate();
 
-        _itemsRepeater = GetTemplateChild(PART_NavigationViewItemMenuItemsHost) as ItemsRepeater;
+        _itemsRepeater = (GetTemplateChild(PART_NavigationViewItemMenuItemsHost) as ItemsRepeater)!;
-        _selectionIndicator = GetTemplateChild(PART_SelectionIndicator) as Microsoft.UI.Xaml.Shapes.Rectangle;
+        _selectionIndicator = (GetTemplateChild(PART_SelectionIndicator) as Microsoft.UI.Xaml.Shapes.Rectangle)!;
 
         UpdateSelectionBorder();
     }

Wino.Mail.WinUI/Controls/Advanced/WinoItemsView.cs

@@ -15,7 +15,7 @@ public partial class WinoItemsView : ItemsView
     private ScrollView? _internalScrollView;
 
     [GeneratedDependencyProperty]
-    public partial ICommand LoadMoreCommand { get; set; }
+    public partial ICommand? LoadMoreCommand { get; set; }
 
     public IEnumerable<object>? CastedItemsSource => ItemsSource as IEnumerable<object>;
 

Wino.Mail.WinUI/Controls/ImagePreviewControl.cs

@@ -60,13 +60,13 @@ public partial class ImagePreviewControl : Control
 
     #endregion
 
-    private Ellipse Ellipse;
+    private Ellipse Ellipse = null!;
-    private Grid InitialsGrid;
+    private Grid InitialsGrid = null!;
-    private TextBlock InitialsTextblock;
+    private TextBlock InitialsTextblock = null!;
-    private Image KnownHostImage;
+    private Image KnownHostImage = null!;
-    private Border FaviconSquircle;
+    private Border FaviconSquircle = null!;
-    private Image FaviconImage;
+    private Image FaviconImage = null!;
-    private CancellationTokenSource contactPictureLoadingCancellationTokenSource;
+    private CancellationTokenSource contactPictureLoadingCancellationTokenSource = null!;
 
     public ImagePreviewControl()
     {
@@ -77,12 +77,12 @@ public partial class ImagePreviewControl : Control
     {
         base.OnApplyTemplate();
 
-        InitialsGrid = GetTemplateChild(PART_EllipseInitialsGrid) as Grid;
+        InitialsGrid = (GetTemplateChild(PART_EllipseInitialsGrid) as Grid)!;
-        InitialsTextblock = GetTemplateChild(PART_InitialsTextBlock) as TextBlock;
+        InitialsTextblock = (GetTemplateChild(PART_InitialsTextBlock) as TextBlock)!;
-        KnownHostImage = GetTemplateChild(PART_KnownHostImage) as Image;
+        KnownHostImage = (GetTemplateChild(PART_KnownHostImage) as Image)!;
-        Ellipse = GetTemplateChild(PART_Ellipse) as Ellipse;
+        Ellipse = (GetTemplateChild(PART_Ellipse) as Ellipse)!;
-        FaviconSquircle = GetTemplateChild(PART_FaviconSquircle) as Border;
+        FaviconSquircle = (GetTemplateChild(PART_FaviconSquircle) as Border)!;
-        FaviconImage = GetTemplateChild(PART_FaviconImage) as Image;
+        FaviconImage = (GetTemplateChild(PART_FaviconImage) as Image)!;
 
         UpdateInformation();
     }
@@ -101,7 +101,7 @@ public partial class ImagePreviewControl : Control
         // Cancel active image loading if exists.
         if (!contactPictureLoadingCancellationTokenSource?.IsCancellationRequested ?? false)
         {
-            contactPictureLoadingCancellationTokenSource.Cancel();
+            contactPictureLoadingCancellationTokenSource!.Cancel();
         }
 
         string contactPicture = SenderContactPicture;
@@ -120,7 +120,9 @@ public partial class ImagePreviewControl : Control
             {
                 // Show favicon in squircle
                 FaviconSquircle.Visibility = Visibility.Visible;
+                if (InitialsGrid != null)
                     InitialsGrid.Visibility = Visibility.Collapsed;
+                if (KnownHostImage != null)
                     KnownHostImage.Visibility = Visibility.Collapsed;
 
                 var bitmapImage = await GetBitmapImageAsync(contactPicture);
@@ -133,8 +135,11 @@ public partial class ImagePreviewControl : Control
             else
             {
                 // Show normal avatar (tondo)
+                if (FaviconSquircle != null)
                     FaviconSquircle.Visibility = Visibility.Collapsed;
+                if (KnownHostImage != null)
                     KnownHostImage.Visibility = Visibility.Collapsed;
+                if (InitialsGrid != null)
                     InitialsGrid.Visibility = Visibility.Visible;
                 contactPictureLoadingCancellationTokenSource = new CancellationTokenSource();
                 try
@@ -145,7 +150,9 @@ public partial class ImagePreviewControl : Control
                     {
                         if (!contactPictureLoadingCancellationTokenSource?.Token.IsCancellationRequested ?? false)
                         {
+                            if (Ellipse != null)
                                 Ellipse.Fill = brush;
+                            if (InitialsTextblock != null)
                                 InitialsTextblock.Text = string.Empty;
                         }
                     }
@@ -158,19 +165,24 @@ public partial class ImagePreviewControl : Control
         }
         else
         {
+            if (FaviconSquircle != null)
                 FaviconSquircle.Visibility = Visibility.Collapsed;
+            if (KnownHostImage != null)
                 KnownHostImage.Visibility = Visibility.Collapsed;
+            if (InitialsGrid != null)
                 InitialsGrid.Visibility = Visibility.Visible;
 
             var colorHash = new ColorHash();
             var rgb = colorHash.Rgb(FromAddress);
 
+            if (Ellipse != null)
                 Ellipse.Fill = new SolidColorBrush(Color.FromArgb(rgb.A, rgb.R, rgb.G, rgb.B));
+            if (InitialsTextblock != null)
                 InitialsTextblock.Text = ExtractInitialsFromName(FromName);
         }
     }
 
-    private static async Task<ImageBrush> GetContactImageBrushAsync(string base64)
+    private static async Task<ImageBrush?> GetContactImageBrushAsync(string base64)
     {
         // Load the image from base64 string.
 
@@ -181,7 +193,7 @@ public partial class ImagePreviewControl : Control
         return new ImageBrush() { ImageSource = bitmapImage };
     }
 
-    private static async Task<BitmapImage> GetBitmapImageAsync(string base64)
+    private static async Task<BitmapImage?> GetBitmapImageAsync(string base64)
     {
         try
         {

Wino.Mail.WinUI/Controls/ListView/WinoMailItemContainerStyleSelector.cs

@@ -15,6 +15,6 @@ public partial class WinoMailItemContainerStyleSelector : StyleSelector
         if (item is ThreadMailItemViewModel)
             return ThreadStyle ?? throw new Exception($"Missing style for {nameof(ThreadMailItemViewModel)}");
 
-        return null;
+        return base.SelectStyleCore(item, container);
     }
 }

Wino.Mail.WinUI/Controls/WebViewEditorControl.cs

@@ -19,9 +19,9 @@ namespace Wino.Mail.Controls;
 
 public sealed partial class WebViewEditorControl : Control, IDisposable
 {
-    private readonly INativeAppService _nativeAppService = App.Current.Services.GetService<INativeAppService>();
+    private readonly INativeAppService _nativeAppService = App.Current.Services.GetService<INativeAppService>()!;
-    private readonly IFontService _fontService = App.Current.Services.GetService<IFontService>();
+    private readonly IFontService _fontService = App.Current.Services.GetService<IFontService>()!;
-    private readonly IPreferencesService _preferencesService = App.Current.Services.GetService<IPreferencesService>();
+    private readonly IPreferencesService _preferencesService = App.Current.Services.GetService<IPreferencesService>()!;
 
     [GeneratedDependencyProperty]
     public partial bool IsEditorDarkMode { get; set; }
@@ -131,7 +131,7 @@ public sealed partial class WebViewEditorControl : Control, IDisposable
     }
 
     private const string PART_WebView = "WebView";
-    private WebView2 _chromium;
+    private WebView2 _chromium = null!;
     private bool _disposedValue;
     private readonly TaskCompletionSource<bool> _domLoadedTask = new();
 
@@ -146,7 +146,7 @@ public sealed partial class WebViewEditorControl : Control, IDisposable
     {
         base.OnApplyTemplate();
 
-        _chromium = GetTemplateChild(PART_WebView) as WebView2;
+        _chromium = (GetTemplateChild(PART_WebView) as WebView2)!;
 
         await InitializeComponent();
     }
@@ -175,7 +175,7 @@ public sealed partial class WebViewEditorControl : Control, IDisposable
         IsEditorDarkMode = !IsEditorDarkMode;
     }
 
-    public async Task<string> GetHtmlBodyAsync()
+    public async Task<string?> GetHtmlBodyAsync()
     {
         var editorContent = await _chromium.ExecuteScriptFunctionSafeAsync("GetHTMLContent");
 
@@ -273,6 +273,8 @@ public sealed partial class WebViewEditorControl : Control, IDisposable
     {
         var change = JsonSerializer.Deserialize(args.WebMessageAsJson, DomainModelsJsonContext.Default.WebViewMessage);
 
+        if (change == null) return;
+
         if (change.Type == "bold")
         {
             _isEditorBoldInternal = change.Value == "true";

Wino.Mail.WinUI/Controls/WinoExpander.cs

@@ -13,9 +13,9 @@ public partial class WinoExpander : Control
     private const string PART_ContentAreaWrapper = "ContentAreaWrapper";
     private const string PART_ContentArea = "ContentArea";
 
-    private ContentControl HeaderGrid;
+    private ContentControl HeaderGrid = null!;
-    private ContentControl ContentArea;
+    private ContentControl ContentArea = null!;
-    private Grid ContentAreaWrapper;
+    private Grid ContentAreaWrapper = null!;
 
     public static readonly DependencyProperty HeaderProperty = DependencyProperty.Register(nameof(Header), typeof(UIElement), typeof(WinoExpander), new PropertyMetadata(null));
     public static readonly DependencyProperty ContentProperty = DependencyProperty.Register(nameof(Content), typeof(UIElement), typeof(WinoExpander), new PropertyMetadata(null));
@@ -50,9 +50,9 @@ public partial class WinoExpander : Control
     {
         base.OnApplyTemplate();
 
-        HeaderGrid = GetTemplateChild(PART_HeaderGrid) as ContentControl;
+        HeaderGrid = (GetTemplateChild(PART_HeaderGrid) as ContentControl)!;
-        ContentAreaWrapper = GetTemplateChild(PART_ContentAreaWrapper) as Grid;
+        ContentAreaWrapper = (GetTemplateChild(PART_ContentAreaWrapper) as Grid)!;
-        ContentArea = GetTemplateChild(PART_ContentArea) as ContentControl;
+        ContentArea = (GetTemplateChild(PART_ContentArea) as ContentControl)!;
 
         Guard.IsNotNull(HeaderGrid, nameof(HeaderGrid));
         Guard.IsNotNull(ContentAreaWrapper, nameof(ContentAreaWrapper));

Wino.Mail.WinUI/Controls/WinoSwipeControlItems.cs

@@ -60,7 +60,7 @@ public partial class WinoSwipeControlItems : SwipeItems
         this.Add(swipeItem);
     }
 
-    private SwipeItem GetSwipeItem(MailOperation operation)
+    private SwipeItem? GetSwipeItem(MailOperation operation)
     {
         if (MailItem == null) return null;
 
@@ -72,18 +72,18 @@ public partial class WinoSwipeControlItems : SwipeItems
         {
             var singleItem = MailItem as MailItemViewModel;
 
-            if (operation == MailOperation.MarkAsRead && singleItem.IsRead)
+            if (singleItem != null && operation == MailOperation.MarkAsRead && singleItem.IsRead)
                 finalOperation = MailOperation.MarkAsUnread;
-            else if (operation == MailOperation.MarkAsUnread && !singleItem.IsRead)
+            else if (singleItem != null && operation == MailOperation.MarkAsUnread && !singleItem.IsRead)
                 finalOperation = MailOperation.MarkAsRead;
         }
         else
         {
             var threadItem = MailItem as ThreadMailItemViewModel;
 
-            if (operation == MailOperation.MarkAsRead && threadItem.ThreadEmails.All(a => a.IsRead))
+            if (threadItem != null && operation == MailOperation.MarkAsRead && threadItem.ThreadEmails.All(a => a.IsRead))
                 finalOperation = MailOperation.MarkAsUnread;
-            else if (operation == MailOperation.MarkAsUnread && threadItem.ThreadEmails.All(a => !a.IsRead))
+            else if (threadItem != null && operation == MailOperation.MarkAsUnread && threadItem.ThreadEmails.All(a => !a.IsRead))
                 finalOperation = MailOperation.MarkAsRead;
         }
 
@@ -114,18 +114,21 @@ public partial class WinoSwipeControlItems : SwipeItems
         {
             var singleItem = MailItem as MailItemViewModel;
 
+            if (singleItem != null)
+            {
                 if (SwipeOperation == MailOperation.MarkAsRead && singleItem.IsRead)
                     finalOperation = MailOperation.MarkAsUnread;
                 else if (SwipeOperation == MailOperation.MarkAsUnread && !singleItem.IsRead)
                     finalOperation = MailOperation.MarkAsRead;
             }
+        }
         else
         {
             var threadItem = MailItem as ThreadMailItemViewModel;
 
-            if (SwipeOperation == MailOperation.MarkAsRead && threadItem.ThreadEmails.All(a => a.IsRead))
+            if (threadItem != null && SwipeOperation == MailOperation.MarkAsRead && threadItem.ThreadEmails.All(a => a.IsRead))
                 finalOperation = MailOperation.MarkAsUnread;
-            else if (SwipeOperation == MailOperation.MarkAsUnread && threadItem.ThreadEmails.All(a => !a.IsRead))
+            else if (threadItem != null && SwipeOperation == MailOperation.MarkAsUnread && threadItem.ThreadEmails.All(a => !a.IsRead))
                 finalOperation = MailOperation.MarkAsRead;
         }
 

Wino.Mail.WinUI/Dialogs/AccountReorderDialog.xaml.cs

@@ -1,4 +1,5 @@
-using System.Collections.ObjectModel;
+using System;
+using System.Collections.ObjectModel;
 using System.Linq;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.UI.Xaml.Controls;
@@ -9,16 +10,16 @@ namespace Wino.Dialogs;
 
 public sealed partial class AccountReorderDialog : ContentDialog
 {
-    public ObservableCollection<IAccountProviderDetailViewModel> Accounts { get; }
+    public ObservableCollection<IAccountProviderDetailViewModel> Accounts { get; set; } = null!;
 
     private int count;
     private bool isOrdering = false;
 
-    private readonly IAccountService _accountService = App.Current.Services.GetService<IAccountService>();
+    private readonly IAccountService? _accountService = App.Current.Services.GetService<IAccountService>();
 
-    public AccountReorderDialog(ObservableCollection<IAccountProviderDetailViewModel> accounts)
+    public AccountReorderDialog(ObservableCollection<IAccountProviderDetailViewModel>? accounts)
     {
-        Accounts = accounts;
+        Accounts = accounts ?? throw new ArgumentNullException(nameof(accounts));
 
         count = accounts.Count;
 
@@ -33,7 +34,7 @@ public sealed partial class AccountReorderDialog : ContentDialog
 
     private void DialogClosed(ContentDialog sender, ContentDialogClosedEventArgs args) => Accounts.CollectionChanged -= AccountsChanged;
 
-    private async void AccountsChanged(object sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
+    private async void AccountsChanged(object? sender, System.Collections.Specialized.NotifyCollectionChangedEventArgs e)
     {
         if (count - 1 == Accounts.Count)
             isOrdering = true;
@@ -44,6 +45,7 @@ public sealed partial class AccountReorderDialog : ContentDialog
 
             var dict = Accounts.ToDictionary(a => a.StartupEntityId, a => Accounts.IndexOf(a));
 
+            if (_accountService != null)
                 await _accountService.UpdateAccountOrdersAsync(dict);
 
             isOrdering = false;

Wino.Mail.WinUI/Dialogs/CreateAccountAliasDialog.xaml.cs

@@ -7,7 +7,7 @@ namespace Wino.Dialogs;
 
 public sealed partial class CreateAccountAliasDialog : ContentDialog, ICreateAccountAliasDialog
 {
-    public MailAccountAlias CreatedAccountAlias { get; set; }
+    public MailAccountAlias CreatedAccountAlias { get; set; } = null!;
     public CreateAccountAliasDialog()
     {
         InitializeComponent();

Wino.Mail.WinUI/Dialogs/KeyboardShortcutDialog.xaml.cs

@@ -25,7 +25,7 @@ public sealed partial class KeyboardShortcutDialog : ContentDialog
     {
         InitializeComponent();
         AvailableMailOperations = GetAvailableMailOperations();
-        SelectedMailOperation = AvailableMailOperations.FirstOrDefault();
+        SelectedMailOperation = AvailableMailOperations.FirstOrDefault()!;
     }
 
     public KeyboardShortcutDialog(KeyboardShortcut existingShortcut) : this()
@@ -33,7 +33,7 @@ public sealed partial class KeyboardShortcutDialog : ContentDialog
         if (existingShortcut != null)
         {
             KeyInputTextBox.Text = existingShortcut.Key;
-            SelectedMailOperation = AvailableMailOperations.FirstOrDefault(x => x.Operation == existingShortcut.MailOperation);
+            SelectedMailOperation = AvailableMailOperations.FirstOrDefault(x => x.Operation == existingShortcut.MailOperation)!;
 
             var modifiers = existingShortcut.ModifierKeys;
             IsControlPressed = modifiers.HasFlag(ModifierKeys.Control);

Wino.Mail.WinUI/Dialogs/MessageSourceDialog.xaml.cs

@@ -8,8 +8,8 @@ namespace Wino.Mail.Dialogs;
 
 public sealed partial class MessageSourceDialog : ContentDialog
 {
-    private readonly IClipboardService _clipboardService = App.Current.Services.GetService<IClipboardService>();
+    private readonly IClipboardService? _clipboardService = App.Current.Services.GetService<IClipboardService>();
-    public string MessageSource { get; set; }
+    public string MessageSource { get; set; } = string.Empty;
     public bool Copied { get; set; }
     public MessageSourceDialog()
     {
@@ -18,7 +18,7 @@ public sealed partial class MessageSourceDialog : ContentDialog
 
     private void ContentDialog_PrimaryButtonClick(ContentDialog sender, ContentDialogButtonClickEventArgs args)
     {
-        _clipboardService.CopyClipboardAsync(MessageSource);
+        _clipboardService!.CopyClipboardAsync(MessageSource);
         Copied = true;
     }
 }

Wino.Mail.WinUI/Dialogs/MoveMailDialog.xaml.cs

@@ -17,7 +17,7 @@ public sealed partial class MoveMailDialog : ContentDialog
     public static readonly DependencyProperty SelectedFolderProperty = DependencyProperty.Register(nameof(SelectedFolder), typeof(IMailItemFolder), typeof(MoveMailDialog), new PropertyMetadata(null, OnSelectedFolderChanged));
 
 
-    public List<IMailItemFolder> FolderList { get; set; }
+    public List<IMailItemFolder> FolderList { get; set; } = [];
 
     public MoveMailDialog(List<IMailItemFolder> allFolders)
     {
@@ -58,7 +58,7 @@ public sealed partial class MoveMailDialog : ContentDialog
                         container.IsExpanded = !container.IsExpanded;
                     }
                 }
-                SelectedFolder = null;
+                SelectedFolder = null!;
             }
             else
             {

Wino.Mail.WinUI/Dialogs/NewImapSetupDialog.xaml.cs

@@ -43,7 +43,7 @@ public sealed partial class NewImapSetupDialog : ContentDialog,
     public void Complete(bool cancel)
     {
         if (!_getServerInfoTaskCompletionSource.Task.IsCompleted)
-            _getServerInfoTaskCompletionSource.TrySetResult(null);
+            _getServerInfoTaskCompletionSource.TrySetResult(null!);
 
         isDismissRequested = true;
 

Wino.Mail.WinUI/Dialogs/SignatureEditorDialog.xaml.cs

@@ -8,7 +8,7 @@ namespace Wino.Dialogs;
 
 public sealed partial class SignatureEditorDialog : ContentDialog
 {
-    public AccountSignature Result;
+    public AccountSignature Result = null!;
 
     public SignatureEditorDialog()
     {
@@ -51,7 +51,7 @@ public sealed partial class SignatureEditorDialog : ContentDialog
 
     private async void SaveClicked(ContentDialog sender, ContentDialogButtonClickEventArgs args)
     {
-        var newSignature = Regex.Unescape(await WebViewEditor.GetHtmlBodyAsync());
+        var newSignature = Regex.Unescape((await WebViewEditor.GetHtmlBodyAsync())!);
 
         if (Result == null)
         {

Wino.Mail.WinUI/Dialogs/SystemFolderConfigurationDialog.xaml.cs

@@ -5,7 +5,6 @@ using Microsoft.UI.Xaml.Controls;
 using Wino.Core.Domain;
 using Wino.Core.Domain.Entities.Mail;
 using Wino.Core.Domain.Enums;
-using Wino.Core.Domain.Exceptions;
 using Wino.Core.Domain.Models.Folders;
 
 namespace Wino.Dialogs;
@@ -14,14 +13,14 @@ public sealed partial class SystemFolderConfigurationDialog : ContentDialog
 {
     private bool canDismissDialog = false;
 
-    public SystemFolderConfiguration Configuration { get; set; }
+    public SystemFolderConfiguration? Configuration { get; set; }
     public List<MailItemFolder> AvailableFolders { get; }
 
-    public MailItemFolder Sent { get; set; }
+    public MailItemFolder? Sent { get; set; }
-    public MailItemFolder Draft { get; set; }
+    public MailItemFolder? Draft { get; set; }
-    public MailItemFolder Archive { get; set; }
+    public MailItemFolder? Archive { get; set; }
-    public MailItemFolder Junk { get; set; }
+    public MailItemFolder? Junk { get; set; }
-    public MailItemFolder Trash { get; set; }
+    public MailItemFolder? Trash { get; set; }
 
     public SystemFolderConfigurationDialog(List<MailItemFolder> availableFolders)
     {
@@ -29,11 +28,11 @@ public sealed partial class SystemFolderConfigurationDialog : ContentDialog
 
         AvailableFolders = availableFolders;
 
-        Sent = AvailableFolders.Find(a => a.SpecialFolderType == Core.Domain.Enums.SpecialFolderType.Sent);
+        Sent = AvailableFolders.Find(a => a.SpecialFolderType == SpecialFolderType.Sent);
-        Draft = AvailableFolders.Find(a => a.SpecialFolderType == Core.Domain.Enums.SpecialFolderType.Draft);
+        Draft = AvailableFolders.Find(a => a.SpecialFolderType == SpecialFolderType.Draft);
-        Archive = AvailableFolders.Find(a => a.SpecialFolderType == Core.Domain.Enums.SpecialFolderType.Archive);
+        Archive = AvailableFolders.Find(a => a.SpecialFolderType == SpecialFolderType.Archive);
-        Junk = AvailableFolders.Find(a => a.SpecialFolderType == Core.Domain.Enums.SpecialFolderType.Junk);
+        Junk = AvailableFolders.Find(a => a.SpecialFolderType == SpecialFolderType.Junk);
-        Trash = AvailableFolders.Find(a => a.SpecialFolderType == Core.Domain.Enums.SpecialFolderType.Deleted);
+        Trash = AvailableFolders.Find(a => a.SpecialFolderType == SpecialFolderType.Deleted);
     }
 
     private void DialogClosing(ContentDialog sender, ContentDialogClosingEventArgs args)
@@ -46,21 +45,21 @@ public sealed partial class SystemFolderConfigurationDialog : ContentDialog
 
     private void SaveClicked(ContentDialog sender, ContentDialogButtonClickEventArgs args)
     {
-        ValidationErrorTextBlock.Text = string.Empty;
+        ValidationErrorTextBlock!.Text = string.Empty;
 
-        var allSpecialFolders = new List<MailItemFolder>()
+        var allSpecialFolders = new List<MailItemFolder?>()
         {
             Sent, Draft, Archive, Trash, Junk
         };
 
         if (allSpecialFolders.Any(a => a != null && a.SpecialFolderType == SpecialFolderType.Inbox))
-            ValidationErrorTextBlock.Text = Translator.SystemFolderConfigDialogValidation_InboxSelected;
+            ValidationErrorTextBlock!.Text = Translator.SystemFolderConfigDialogValidation_InboxSelected;
 
-        if (new HashSet<Guid>(allSpecialFolders.Where(a => a != null).Select(x => x.Id)).Count != allSpecialFolders.Where(a => a != null).Count())
+        if (new HashSet<Guid>(allSpecialFolders.Where(a => a != null).Select(x => x!.Id)).Count != allSpecialFolders.Where(a => a != null).Count())
-            ValidationErrorTextBlock.Text = Translator.SystemFolderConfigDialogValidation_DuplicateSystemFolders;
+            ValidationErrorTextBlock!.Text = Translator.SystemFolderConfigDialogValidation_DuplicateSystemFolders;
 
         // Check if we can save.
-        if (string.IsNullOrEmpty(ValidationErrorTextBlock.Text))
+        if (string.IsNullOrEmpty(ValidationErrorTextBlock!.Text))
         {
             var configuration = new SystemFolderConfiguration(Sent, Draft, Archive, Trash, Junk);
 

Wino.Mail.WinUI/MenuFlyouts/FilterMenuFlyout.cs

@@ -110,6 +110,7 @@ public partial class FilterMenuFlyout : MenuFlyout
 
             var optionModel = button.Tag as SortingOption;
 
+            if (optionModel != null)
                 SelectSortingOption(optionModel);
         }
     }
@@ -124,6 +125,7 @@ public partial class FilterMenuFlyout : MenuFlyout
 
             var optionModel = button.Tag as FilterOption;
 
+            if (optionModel != null)
                 SelectFilterOption(optionModel);
         }
     }

Wino.Mail.WinUI/MenuFlyouts/MoveButtonFlyout.cs

@@ -1,9 +1,9 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using Windows.Foundation;
 using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
+using Windows.Foundation;
 using Wino.Core.Domain.Entities.Mail;
 
 namespace Wino.MenuFlyouts;
@@ -15,7 +15,7 @@ public class MoveButtonMenuItemClickedEventArgs
 
 public partial class MoveButtonFlyout : MenuFlyout
 {
-    public event TypedEventHandler<MoveButtonFlyout, MoveButtonMenuItemClickedEventArgs> MenuItemClick;
+    public event TypedEventHandler<MoveButtonFlyout, MoveButtonMenuItemClickedEventArgs> MenuItemClick = delegate { };
     public static readonly DependencyProperty FoldersProperty = DependencyProperty.Register(nameof(Folders), typeof(List<MailItemFolder>), typeof(MoveButtonFlyout), new PropertyMetadata(null, new PropertyChangedCallback(OnFoldersChanged)));
 
     public List<MailItemFolder> Folders
@@ -66,7 +66,7 @@ public partial class MoveButtonFlyout : MenuFlyout
 
     private void MenuItemClicked(object sender, RoutedEventArgs e)
     {
-        var clickedFolder = (sender as MenuFlyoutItem).Tag as MailItemFolder;
+        var clickedFolder = ((MenuFlyoutItem)sender).Tag as MailItemFolder ?? throw new InvalidOperationException("Clicked folder is null.");
 
         MenuItemClick?.Invoke(this, new MoveButtonMenuItemClickedEventArgs()
         {

Wino.Mail.WinUI/MenuFlyouts/WinoOperationFlyout.cs

@@ -7,7 +7,7 @@ namespace Wino.MenuFlyouts;
 
 public partial class WinoOperationFlyout<TActionType> : MenuFlyout, IDisposable where TActionType : class
 {
-    public TActionType ClickedOperation { get; set; }
+    public TActionType ClickedOperation { get; set; } = null!;
 
     protected readonly IEnumerable<TActionType> AvailableActions;
 

Wino.Mail.WinUI/Selectors/AccountProviderViewModelTemplateSelector.cs

@@ -1,4 +1,5 @@
-using Microsoft.UI.Xaml;
+using System;
+using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
 using Wino.Core.ViewModels.Data;
 
@@ -6,14 +7,14 @@ namespace Wino.Selectors;
 
 public partial class AccountProviderViewModelTemplateSelector : DataTemplateSelector
 {
-    public DataTemplate RootAccountTemplate { get; set; }
+    public DataTemplate? RootAccountTemplate { get; set; }
-    public DataTemplate MergedAccountTemplate { get; set; }
+    public DataTemplate? MergedAccountTemplate { get; set; }
 
     protected override DataTemplate SelectTemplateCore(object item, DependencyObject container)
     {
         if (item is MergedAccountProviderDetailViewModel)
-            return MergedAccountTemplate;
+            return MergedAccountTemplate ?? throw new ArgumentException(nameof(MergedAccountTemplate));
         else
-            return RootAccountTemplate;
+            return RootAccountTemplate ?? throw new ArgumentException(nameof(RootAccountTemplate));
     }
 }

Wino.Mail.WinUI/Selectors/AccountReorderTemplateSelector.cs

@@ -1,4 +1,5 @@
-using Microsoft.UI.Xaml;
+using System;
+using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
 using Wino.Core.ViewModels.Data;
 
@@ -6,16 +7,16 @@ namespace Wino.Selectors;
 
 public partial class AccountReorderTemplateSelector : DataTemplateSelector
 {
-    public DataTemplate MergedAccountReorderTemplate { get; set; }
+    public DataTemplate? MergedAccountReorderTemplate { get; set; }
-    public DataTemplate RootAccountReorderTemplate { get; set; }
+    public DataTemplate? RootAccountReorderTemplate { get; set; }
 
     protected override DataTemplate SelectTemplateCore(object item, DependencyObject container)
     {
         if (item is MergedAccountProviderDetailViewModel)
         {
-            return MergedAccountReorderTemplate;
+            return MergedAccountReorderTemplate ?? throw new ArgumentException(nameof(MergedAccountReorderTemplate));
         }
 
-        return RootAccountReorderTemplate;
+        return RootAccountReorderTemplate ?? throw new ArgumentException(nameof(RootAccountReorderTemplate));
     }
 }

Wino.Mail.WinUI/Selectors/MailItemDisplayModePreviewTemplateSelector.cs

@@ -1,4 +1,5 @@
-using Microsoft.UI.Xaml;
+using System;
+using Microsoft.UI.Xaml;
 using Microsoft.UI.Xaml.Controls;
 using Wino.Core.Domain.Enums;
 
@@ -9,9 +10,9 @@ namespace Wino.Selectors;
 /// </summary>
 public partial class MailItemDisplayModePreviewTemplateSelector : DataTemplateSelector
 {
-    public DataTemplate CompactTemplate { get; set; }
+    public DataTemplate? CompactTemplate { get; set; }
-    public DataTemplate MediumTemplate { get; set; }
+    public DataTemplate? MediumTemplate { get; set; }
-    public DataTemplate SpaciousTemplate { get; set; }
+    public DataTemplate? SpaciousTemplate { get; set; }
 
     protected override DataTemplate SelectTemplateCore(object item, DependencyObject container)
     {
@@ -20,11 +21,11 @@ public partial class MailItemDisplayModePreviewTemplateSelector : DataTemplateSe
             switch (mode)
             {
                 case MailListDisplayMode.Spacious:
-                    return SpaciousTemplate;
+                    return SpaciousTemplate ?? throw new ArgumentException(nameof(SpaciousTemplate));
                 case MailListDisplayMode.Medium:
-                    return MediumTemplate;
+                    return MediumTemplate ?? throw new ArgumentException(nameof(MediumTemplate));
                 case MailListDisplayMode.Compact:
-                    return CompactTemplate;
+                    return CompactTemplate ?? throw new ArgumentException(nameof(CompactTemplate));
             }
         }
 

Wino.Mail.WinUI/Services/DialogService.cs

@@ -149,7 +149,7 @@ public class DialogService : DialogServiceBase, IMailDialogService
         return accountPicker.PickedAccount;
     }
 
-    public async Task<AccountSignature> ShowSignatureEditorDialog(AccountSignature signatureModel = null)
+    public async Task<AccountSignature> ShowSignatureEditorDialog(AccountSignature? signatureModel = null)
     {
         SignatureEditorDialog signatureEditorDialog;
         if (signatureModel != null)
@@ -169,7 +169,7 @@ public class DialogService : DialogServiceBase, IMailDialogService
 
         var result = await HandleDialogPresentationAsync(signatureEditorDialog);
 
-        return result == ContentDialogResult.Primary ? signatureEditorDialog.Result : null;
+        return result == ContentDialogResult.Primary ? signatureEditorDialog.Result : null!;
     }
 
     public async Task ShowMessageSourceDialogAsync(string messageSource)

Wino.Mail.WinUI/Services/NavigationService.cs

@@ -74,7 +74,7 @@ public class NavigationService : NavigationServiceBase, INavigationService
     }
 
     public bool Navigate(WinoPage page,
-                         object parameter = null,
+                         object? parameter = null,
                          NavigationReferenceFrame frame = NavigationReferenceFrame.ShellFrame,
                          NavigationTransitionType transition = NavigationTransitionType.None)
     {

Wino.Mail.WinUI/Services/ProviderService.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Linq;
 using Wino.Core.Domain.Enums;
 using Wino.Core.Domain.Interfaces;
@@ -15,7 +16,7 @@ public class ProviderService : IProviderService
     {
         var details = GetAvailableProviders();
 
-        return details.FirstOrDefault(a => a.Type == type);
+        return details.FirstOrDefault(a => a.Type == type) ?? throw new InvalidOperationException($"Provider detail not found for type: {type}");
     }
 
     public List<IProviderDetail> GetAvailableProviders()

Wino.Mail.WinUI/ShellWindow.xaml.cs

@@ -85,7 +85,11 @@ public sealed partial class ShellWindow : WindowEx, IWinoShellWindow, IRecipient
         WeakReferenceMessenger.Default.Send(new DisposeRenderingFrameRequested());
     }
 
-    private void MainFrameNavigated(object sender, Microsoft.UI.Xaml.Navigation.NavigationEventArgs e) => ShellTitleBar.Content = (e.Content as BasePage).ShellContent;
+    private void MainFrameNavigated(object sender, Microsoft.UI.Xaml.Navigation.NavigationEventArgs e)
+    {
+        if (e.Content is BasePage basePage)
+            ShellTitleBar.Content = basePage.ShellContent;
+    }
 
     private void PaneButtonClicked(Microsoft.UI.Xaml.Controls.TitleBar sender, object args)
     {

Wino.Mail.WinUI/Views/ComposePage.xaml.cs

@@ -41,7 +41,7 @@ public sealed partial class ComposePage : ComposePageAbstract,
         InitializeComponent();
     }
 
-    private async void GlobalFocusManagerGotFocus(object sender, FocusManagerGotFocusEventArgs e)
+    private async void GlobalFocusManagerGotFocus(object? sender, FocusManagerGotFocusEventArgs e)
     {
         // In order to delegate cursor to the inner editor for WebView2.
         // When the control got focus, we invoke script to focus the editor.
@@ -60,7 +60,7 @@ public sealed partial class ComposePage : ComposePageAbstract,
             x => box.TextChanged += x,
             x => box.TextChanged -= x)
                 .Throttle(TimeSpan.FromMilliseconds(120))
-                .ObserveOn(SynchronizationContext.Current)
+                .ObserveOn(SynchronizationContext.Current!)
                 .Subscribe(t =>
                 {
                     if (t.EventArgs.Reason == AutoSuggestionBoxTextChangeReason.UserInput)
@@ -305,10 +305,15 @@ public sealed partial class ComposePage : ComposePageAbstract,
         ImportanceFlyout.Hide();
         ImportanceSplitButton.IsChecked = true;
 
-        if (sender is Button senderButton)
+        if (sender is Button senderButton && senderButton.Tag is MessageImportance importance)
         {
-            ViewModel.SelectedMessageImportance = (MessageImportance)senderButton.Tag;
+            ViewModel.SelectedMessageImportance = importance;
-            ((ImportanceSplitButton.Content as Viewbox).Child as SymbolIcon).Symbol = (senderButton.Content as SymbolIcon).Symbol;
+            if (ImportanceSplitButton.Content is Viewbox viewbox && 
+                viewbox.Child is SymbolIcon symbolIcon && 
+                senderButton.Content is SymbolIcon contentIcon)
+            {
+                symbolIcon.Symbol = contentIcon.Symbol;
+            }
         }
     }
 
@@ -332,7 +337,7 @@ public sealed partial class ComposePage : ComposePageAbstract,
                     _ => null
                 };
 
-                AccountContact addedItem = null;
+                AccountContact? addedItem = null;
 
                 if (addressCollection != null)
                     addedItem = await ViewModel.GetAddressInformationAsync(currentText, addressCollection);

Wino.Mail.WinUI/Views/ImapSetup/AdvancedImapSetupPage.xaml.cs

@@ -200,15 +200,15 @@ public sealed partial class AdvancedImapSetupPage : Page
             IncomingServerPassword = PasswordBox.Password,
             IncomingServerType = Core.Domain.Enums.CustomIncomingServerType.IMAP4,
             IncomingServerUsername = UsernameBox.Text,
-            IncomingAuthenticationMethod = (IncomingAuthenticationMethod.SelectedItem as ImapAuthenticationMethodModel).ImapAuthenticationMethod,
+            IncomingAuthenticationMethod = (IncomingAuthenticationMethod.SelectedItem as ImapAuthenticationMethodModel)!.ImapAuthenticationMethod,
-            IncomingServerSocketOption = (IncomingConnectionSecurity.SelectedItem as ImapConnectionSecurityModel).ImapConnectionSecurity,
+            IncomingServerSocketOption = (IncomingConnectionSecurity.SelectedItem as ImapConnectionSecurityModel)!.ImapConnectionSecurity,
             IncomingServerPort = IncomingServerPortBox.Text,
 
             OutgoingServer = GetServerWithoutPort(OutgoingServerBox.Text),
             OutgoingServerPort = OutgoingServerPort.Text,
             OutgoingServerPassword = OutgoingPasswordBox.Password,
-            OutgoingAuthenticationMethod = (OutgoingAuthenticationMethod.SelectedItem as ImapAuthenticationMethodModel).ImapAuthenticationMethod,
+            OutgoingAuthenticationMethod = (OutgoingAuthenticationMethod.SelectedItem as ImapAuthenticationMethodModel)!.ImapAuthenticationMethod,
-            OutgoingServerSocketOption = (OutgoingConnectionSecurity.SelectedItem as ImapConnectionSecurityModel).ImapConnectionSecurity,
+            OutgoingServerSocketOption = (OutgoingConnectionSecurity.SelectedItem as ImapConnectionSecurityModel)!.ImapConnectionSecurity,
             OutgoingServerUsername = OutgoingUsernameBox.Text,
 
             ProxyServer = ProxyServerBox.Text,

Wino.Mail.WinUI/Views/ImapSetup/ImapConnectionFailedPage.xaml.cs

@@ -13,10 +13,10 @@ namespace Wino.Views.ImapSetup;
 
 public sealed partial class ImapConnectionFailedPage : Page
 {
-    private string _protocolLog;
+    private string? _protocolLog;
 
-    private readonly IClipboardService _clipboardService = App.Current.Services.GetService<IClipboardService>();
+    private readonly IClipboardService _clipboardService = App.Current.Services.GetService<IClipboardService>()!;
-    private readonly IMailDialogService _dialogService = App.Current.Services.GetService<IMailDialogService>();
+    private readonly IMailDialogService _dialogService = App.Current.Services.GetService<IMailDialogService>()!;
 
     public ImapConnectionFailedPage()
     {

Wino.Mail.WinUI/Views/ImapSetup/TestingImapConnectionPage.xaml.cs

@@ -15,8 +15,8 @@ namespace Wino.Views.ImapSetup;
 
 public sealed partial class TestingImapConnectionPage : Page
 {
-    private AutoDiscoverySettings autoDiscoverySettings;
+    private AutoDiscoverySettings autoDiscoverySettings = null!;
-    private CustomServerInformation serverInformationToTest;
+    private CustomServerInformation serverInformationToTest = null!;
 
     public TestingImapConnectionPage()
     {

Wino.Mail.WinUI/Views/ImapSetup/WelcomeImapSetupPage.xaml.cs

@@ -19,7 +19,7 @@ namespace Wino.Views.ImapSetup;
 
 public sealed partial class WelcomeImapSetupPage : Page
 {
-    private readonly IAutoDiscoveryService _autoDiscoveryService = App.Current.Services.GetService<IAutoDiscoveryService>();
+    private readonly IAutoDiscoveryService _autoDiscoveryService = App.Current.Services.GetService<IAutoDiscoveryService>()!;
 
     public WelcomeImapSetupPage()
     {

Wino.Mail.WinUI/Views/MailListPage.xaml

@@ -184,14 +184,9 @@
                 LostFocus="SearchBarUnfocused"
                 PlaceholderText="{x:Bind domain:Translator.SearchBarPlaceholder}"
                 QueryIcon="Find"
+                QuerySubmitted="SearchbarQuerySubmitted"
                 Text="{x:Bind ViewModel.SearchQuery, Mode=TwoWay}"
-                TextChanged="SearchBar_TextChanged">
+                TextChanged="SearchBar_TextChanged" />
-                <i:Interaction.Behaviors>
-                    <i:EventTriggerBehavior EventName="QuerySubmitted">
-                        <i:InvokeCommandAction Command="{x:Bind ViewModel.PerformSearchCommand}" />
-                    </i:EventTriggerBehavior>
-                </i:Interaction.Behaviors>
-            </AutoSuggestBox>
         </Grid>
     </wino:BasePage.ShellContent>
 

Wino.Mail.WinUI/Views/MailListPage.xaml.cs

@@ -188,7 +188,7 @@ public sealed partial class MailListPage : MailListPageAbstract,
             targetItems = ViewModel.MailCollection.SelectedItems;
             var availableActions = ViewModel.GetAvailableMailActions(targetItems);
 
-            if (!availableActions?.Any() ?? false) return;
+            if (availableActions == null || !availableActions.Any()) return;
 
             var clickedOperation = await GetMailOperationFromFlyoutAsync(availableActions, control, p.X, p.Y);
 
@@ -738,4 +738,10 @@ public sealed partial class MailListPage : MailListPageAbstract,
 
         await WinoClickItemInternalAsync(e.ClickedItem);
     }
+
+    private void SearchbarQuerySubmitted(AutoSuggestBox sender, AutoSuggestBoxQuerySubmittedEventArgs args)
+    {
+        if (ViewModel.PerformSearchCommand.CanExecute(null))
+            ViewModel.PerformSearchCommand.Execute(null);
+    }
 }

Wino.Mail.WinUI/Views/MailRenderingPage.xaml.cs

@@ -28,8 +28,8 @@ public sealed partial class MailRenderingPage : MailRenderingPageAbstract,
     IRecipient<CancelRenderingContentRequested>,
     IRecipient<ApplicationThemeChanged>
 {
-    private readonly IPreferencesService _preferencesService = App.Current.Services.GetService<IPreferencesService>();
+    private readonly IPreferencesService _preferencesService = App.Current.Services.GetService<IPreferencesService>()!;
-    private readonly IMailDialogService _dialogService = App.Current.Services.GetService<IMailDialogService>();
+    private readonly IMailDialogService _dialogService = App.Current.Services.GetService<IMailDialogService>()!;
 
     private bool isRenderingInProgress = false;
     private TaskCompletionSource<bool> DOMLoadedTask = new TaskCompletionSource<bool>();
@@ -232,7 +232,7 @@ public sealed partial class MailRenderingPage : MailRenderingPageAbstract,
         // TODO: Check external link navigation setting is enabled.
         // Open all external urls in launcher.
 
-        if (args.Cancel && Uri.TryCreate(args.Uri, UriKind.Absolute, out Uri newUri))
+        if (args.Cancel && Uri.TryCreate(args.Uri, UriKind.Absolute, out Uri? newUri) && newUri != null)
         {
             await Launcher.LaunchUriAsync(newUri);
         }
@@ -242,7 +242,7 @@ public sealed partial class MailRenderingPage : MailRenderingPageAbstract,
     {
         if (e.ClickedItem is MailAttachmentViewModel attachmentViewModel)
         {
-            ViewModel.OpenAttachmentCommand.Execute(attachmentViewModel);
+            ViewModel?.OpenAttachmentCommand.Execute(attachmentViewModel);
         }
     }
 

Wino.Mail.WinUI/Wino.Mail.WinUI.csproj

@@ -11,7 +11,16 @@
     <UseWinUI>true</UseWinUI>
     <EnableMsixTooling>true</EnableMsixTooling>
     <Nullable>enable</Nullable>
+
+	<!-- AOT / Trimming -->
+	<PublishAot Condition="'$(Configuration)' == 'Debug'">False</PublishAot>
+	<PublishAot Condition="'$(Configuration)' != 'Debug'">True</PublishAot>
+	<TreatWarningsAsErrors>True</TreatWarningsAsErrors>
+	<AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+	  
+	<!-- Single instancing -->
     <DefineConstants>$(DefineConstants);DISABLE_XAML_GENERATED_MAIN</DefineConstants>
+  
 </PropertyGroup>
   <ItemGroup>
     <Content Remove="Assets\BadgeLogo.scale-100.png" />
@@ -262,8 +271,11 @@
   <PropertyGroup>  
     <PublishReadyToRun Condition="'$(Configuration)' == 'Debug'">False</PublishReadyToRun>
     <PublishReadyToRun Condition="'$(Configuration)' != 'Debug'">True</PublishReadyToRun>
+	  
+	<!-- Trimming -->
     <PublishTrimmed Condition="'$(Configuration)' == 'Debug'">False</PublishTrimmed>
     <PublishTrimmed Condition="'$(Configuration)' != 'Debug'">True</PublishTrimmed>
+	  
     <GenerateTemporaryStoreCertificate>True</GenerateTemporaryStoreCertificate>
     <GenerateAppInstallerFile>False</GenerateAppInstallerFile>
     <AppxPackageSigningEnabled>True</AppxPackageSigningEnabled>