Enable nullability in all samples (#20379)

samples/AppWithoutLifetime/AppWithoutLifetime.csproj

@@ -2,7 +2,6 @@
   <PropertyGroup>
     <OutputType>WinExe</OutputType>
     <TargetFramework>$(AvsCurrentTargetFramework)</TargetFramework>
-    <Nullable>enable</Nullable>
     <ApplicationManifest>app.manifest</ApplicationManifest>
   </PropertyGroup>
 

samples/BindingDemo/GenericMarkupExtension.cs

@@ -5,7 +5,7 @@ namespace BindingDemo;
 
 internal class GenericMarkupExtension<T> : MarkupExtension
 {
-    public T Value { get; set; }
+    public T? Value { get; set; }
 
     public override object ProvideValue(IServiceProvider serviceProvider)
     {

samples/BindingDemo/ViewModels/DataAnnotationsErrorViewModel.cs

@@ -6,7 +6,7 @@ namespace BindingDemo.ViewModels
     {
         [Phone]
         [MaxLength(10)]
-        public string PhoneNumber { get; set; }
+        public string? PhoneNumber { get; set; }
 
         [Range(0, 9)]
         public int LessThan10 { get; set; }

samples/BindingDemo/ViewModels/IndeiErrorViewModel.cs

@@ -9,7 +9,7 @@ namespace BindingDemo.ViewModels
     {
         private int _maximum = 10;
         private int _value;
-        private string _valueError;
+        private string? _valueError;
 
         public IndeiErrorViewModel()
         {
@@ -34,16 +34,16 @@ namespace BindingDemo.ViewModels
             set { this.RaiseAndSetIfChanged(ref _value, value); }
         }
 
-        public event EventHandler<DataErrorsChangedEventArgs> ErrorsChanged;
+        public event EventHandler<DataErrorsChangedEventArgs>? ErrorsChanged;
 
-        public IEnumerable GetErrors(string propertyName)
+        public IEnumerable GetErrors(string? propertyName)
         {
             switch (propertyName)
             {
                 case nameof(Value):
                     return new[] { _valueError };
                 default:
-                    return null;
+                    return Array.Empty<string>();
             }
         }
 

samples/BindingDemo/ViewModels/MainWindowViewModel.cs

@@ -16,10 +16,10 @@ namespace BindingDemo.ViewModels
     {
         private string _booleanString = "True";
         private double _doubleValue = 5.0;
-        private string _stringValue = "Simple Binding";
+        private string? _stringValue = "Simple Binding";
         private bool _booleanFlag = false;
-        private string _currentTime;
+        private string? _currentTime;
-        private NestedCommandViewModel _nested;
+        private NestedCommandViewModel? _nested;
 
         public MainWindowViewModel()
         {
@@ -74,7 +74,7 @@ namespace BindingDemo.ViewModels
             set { this.RaiseAndSetIfChanged(ref _doubleValue, value); }
         }
 
-        public string StringValue
+        public string? StringValue
         {
             get { return _stringValue; }
             set { this.RaiseAndSetIfChanged(ref _stringValue, value); }
@@ -86,7 +86,7 @@ namespace BindingDemo.ViewModels
             set { this.RaiseAndSetIfChanged(ref _booleanFlag, value); }
         }
 
-        public string CurrentTime
+        public string? CurrentTime
         {
             get { return _currentTime; }
             private set { this.RaiseAndSetIfChanged(ref _currentTime, value); }
@@ -99,7 +99,7 @@ namespace BindingDemo.ViewModels
         public ExceptionErrorViewModel ExceptionDataValidation { get; } = new ExceptionErrorViewModel();
         public IndeiErrorViewModel IndeiDataValidation { get; } = new IndeiErrorViewModel();
 
-        public NestedCommandViewModel NestedModel
+        public NestedCommandViewModel? NestedModel
         {
             get { return _nested; }
             private set { this.RaiseAndSetIfChanged(ref _nested, value); }
@@ -119,16 +119,16 @@ namespace BindingDemo.ViewModels
         // Nested class, jsut so we can test it in XAML
         public class TestItem<T> : ViewModelBase
         {
-            private T _value;
+            private T? _value;
-            private string _detail;
+            private string? _detail;
 
-            public T Value
+            public T? Value
             {
                 get { return _value; }
                 set { this.RaiseAndSetIfChanged(ref this._value, value); }
             }
 
-            public string Detail
+            public string? Detail
             {
                 get { return _detail; }
                 set { this.RaiseAndSetIfChanged(ref this._detail, value); }

samples/ControlCatalog.Android/ControlCatalog.Android.csproj

@@ -3,7 +3,6 @@
     <TargetFramework>$(AvsCurrentAndroidTargetFramework)</TargetFramework>
     <SupportedOSPlatformVersion>$(AvsMinSupportedAndroidVersion)</SupportedOSPlatformVersion>
     <OutputType>Exe</OutputType>
-    <Nullable>enable</Nullable>
     <ApplicationId>com.Avalonia.ControlCatalog</ApplicationId>
     <ApplicationVersion>1</ApplicationVersion>
     <ApplicationDisplayVersion>1.0</ApplicationDisplayVersion>

samples/ControlCatalog.Desktop/NativeControls/Gtk/EmbedSample.Gtk.cs

@@ -9,7 +9,7 @@ namespace ControlCatalog.Desktop;
 
 public class EmbedSampleGtk : INativeDemoControl
 {
-    private Process _mplayer;
+    private Process? _mplayer;
 
     public IPlatformHandle CreateControl(bool isSecond, IPlatformHandle parent, Func<IPlatformHandle> createDefault)
     {

samples/ControlCatalog.Desktop/NativeControls/Mac/MacHelper.cs

@@ -20,7 +20,7 @@ internal class MacHelper
 
 internal class MacOSViewHandle : INativeControlHostDestroyableControlHandle
 {
-    private NSView _view;
+    private NSView? _view;
 
     public MacOSViewHandle(NSView view)
     {
@@ -32,7 +32,7 @@ internal class MacOSViewHandle : INativeControlHostDestroyableControlHandle
 
     public void Destroy()
     {
-        _view.Dispose();
+        _view?.Dispose();
         _view = null;
     }
 }

samples/ControlCatalog.Desktop/NativeControls/Win/WinApi.cs

@@ -44,7 +44,7 @@ internal unsafe class WinApi
 
 
     [DllImport("kernel32.dll")]
-    public static extern IntPtr GetModuleHandle(string lpModuleName);
+    public static extern IntPtr GetModuleHandle(string? lpModuleName);
 
     [DllImport("user32.dll", SetLastError = true)]
     public static extern IntPtr CreateWindowEx(

samples/ControlCatalog.Desktop/Program.cs

@@ -74,12 +74,12 @@ namespace ControlCatalog.Desktop
                     {
                         DispatcherTimer.RunOnce(async () =>
                         {
-                            var window = ((IClassicDesktopStyleApplicationLifetime)Application.Current.ApplicationLifetime)
+                            var window = ((IClassicDesktopStyleApplicationLifetime)Application.Current!.ApplicationLifetime!)
-                                .MainWindow;
+                                .MainWindow!;
                             var tc = window.GetLogicalDescendants().OfType<TabControl>().First();
                             foreach (var page in tc.Items.Cast<TabItem>().ToList())
                             {
-                                if (page.Header.ToString() == "DatePicker" || page.Header.ToString() == "TreeView")
+                                if (page.Header?.ToString() is "DatePicker" or "TreeView")
                                     continue;
                                 Console.WriteLine("Selecting " + page.Header);
                                 tc.SelectedItem = page;

samples/ControlCatalog/ControlCatalog.csproj

@@ -2,7 +2,6 @@
   <PropertyGroup>
     <TargetFrameworks>$(AvsCurrentTargetFramework)</TargetFrameworks>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    <Nullable>enable</Nullable>
     <IncludeAvaloniaGenerators>true</IncludeAvaloniaGenerators>
   </PropertyGroup>
   <ItemGroup>

samples/Directory.Build.props

@@ -6,6 +6,7 @@
     <EnableNETAnalyzers>false</EnableNETAnalyzers>
     <GenerateDocumentationFile>false</GenerateDocumentationFile>
     <LangVersion>14.0</LangVersion>
+    <Nullable>enable</Nullable>
     <NoWarn>$(NoWarn);CS8002</NoWarn> <!-- ignore signing warnings for samples -->
   </PropertyGroup>
 

samples/GpuInterop/GpuInterop.csproj

@@ -4,7 +4,6 @@
     <OutputType>Exe</OutputType>
     <TargetFramework>$(AvsCurrentTargetFramework)</TargetFramework>
     <TargetLatestRuntimePatch>true</TargetLatestRuntimePatch>
-    <Nullable>enable</Nullable>
     <UseD3DCompiler>true</UseD3DCompiler>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
 

samples/IntegrationTestApp/IntegrationTestApp.csproj

@@ -2,7 +2,6 @@
   <PropertyGroup>
     <OutputType>WinExe</OutputType>
     <TargetFramework>$(AvsCurrentTargetFramework)</TargetFramework>
-    <Nullable>enable</Nullable>
     <NoWarn>$(NoWarn);AVP1012;AVLN3001</NoWarn>
     <ApplicationManifest>app.manifest</ApplicationManifest>
     <IncludeAvaloniaGenerators>true</IncludeAvaloniaGenerators>

samples/MiniMvvm/MiniMvvm.csproj

@@ -2,7 +2,6 @@
   
   <PropertyGroup>
     <TargetFramework>$(AvsCurrentTargetFramework)</TargetFramework>
-    <Nullable>enable</Nullable>
   </PropertyGroup>
   
   <ItemGroup>

samples/PlatformSanityChecks/Program.cs

@@ -12,12 +12,12 @@ namespace PlatformSanityChecks
 {
     public class Program
     {
-        static Thread UiThread;
+        static Thread UiThread = null!;
         
         static void Main(string[] args)
         {
             UiThread = Thread.CurrentThread;
-            AppBuilder.Configure<App>().RuntimePlatformServicesInitializer();
+            AppBuilder.Configure<App>().RuntimePlatformServicesInitializer!();
             var app = new App();
             
             AvaloniaX11PlatformExtensions.InitializeX11Platform();
@@ -41,13 +41,13 @@ namespace PlatformSanityChecks
             throw new Exception(error);
         }
 
-        static IDisposable Enter([CallerMemberName] string caller = null)
+        static IDisposable Enter([CallerMemberName] string? caller = null)
         {
             Console.WriteLine("Entering " + caller);
             return Disposable.Create(() => { Console.WriteLine("Leaving " + caller); });
         }
 
-        static void EnterLoop(Action<CancellationTokenSource> cb, [CallerMemberName] string caller = null)
+        static void EnterLoop(Action<CancellationTokenSource> cb, [CallerMemberName] string? caller = null)
         {
             using (Enter(caller))
             {

samples/Previewer/MainWindow.xaml.cs

@@ -17,22 +17,22 @@ namespace Previewer
         <TextBlock>Hello world!</TextBlock>
     
         </Window>";
-        private IAvaloniaRemoteTransportConnection _connection;
+        private IAvaloniaRemoteTransportConnection? _connection;
         private Control _errorsContainer;
         private TextBlock _errors;
-        private RemoteWidget _remote;
+        private RemoteWidget? _remote;
 
 
         public MainWindow()
         {
             this.InitializeComponent();
-            var tb = this.FindControl<TextBox>("Xaml");
+            var tb = this.GetControl<TextBox>("Xaml");
             tb.Text = InitialXaml;
-            var scroll = this.FindControl<ScrollViewer>("Remote");
+            var scroll = this.GetControl<ScrollViewer>("Remote");
             var rem = new Center();
             scroll.Content = rem;
-            _errorsContainer = this.FindControl<Control>("ErrorsContainer");
+            _errorsContainer = this.GetControl<Control>("ErrorsContainer");
-            _errors = this.FindControl<TextBlock>("Errors");
+            _errors = this.GetControl<TextBlock>("Errors");
             tb.GetObservable(TextBox.TextProperty).Subscribe(text => _connection?.Send(new UpdateXamlMessage
             {
                 Xaml = text
@@ -70,7 +70,7 @@ namespace Previewer
                     _errorsContainer.IsVisible = result.Error != null;
                     _errors.Text = result.Error ?? "";
                 }
-                if (obj is RequestViewportResizeMessage resize)
+                if (obj is RequestViewportResizeMessage resize && _remote is not null)
                 {
                     _remote.Width = Math.Min(4096, Math.Max(resize.Width, 1));
                     _remote.Height = Math.Min(4096, Math.Max(resize.Height, 1));

samples/RenderDemo/Pages/CustomSkiaPage.cs

@@ -31,7 +31,7 @@ namespace RenderDemo.Pages
 
             public CustomDrawOp(Rect bounds, GlyphRun noSkia)
             {
-                _noSkia = noSkia.TryCreateImmutableGlyphRunReference();
+                _noSkia = noSkia.TryCreateImmutableGlyphRunReference()!;
                 Bounds = bounds;
             }
             
@@ -42,7 +42,7 @@ namespace RenderDemo.Pages
 
             public Rect Bounds { get; }
             public bool HitTest(Point p) => false;
-            public bool Equals(ICustomDrawOperation other) => false;
+            public bool Equals(ICustomDrawOperation? other) => false;
             static Stopwatch St = Stopwatch.StartNew();
             public void Render(ImmediateDrawingContext context)
             {

samples/RenderDemo/Pages/FormattedTextPage.axaml.cs

@@ -57,11 +57,11 @@ namespace RenderDemo.Pages
 
             context.DrawText(formattedText, new Point(10, 0));
 
-            var geometry = formattedText.BuildGeometry(new Point(10 + formattedText.Width + 10, 0));
+            var geometry = formattedText.BuildGeometry(new Point(10 + formattedText.Width + 10, 0))!;
 
             context.DrawGeometry(gradient, null, geometry);
 
-            var highlightGeometry = formattedText.BuildHighlightGeometry(new Point(10 + formattedText.Width + 10, 0));
+            var highlightGeometry = formattedText.BuildHighlightGeometry(new Point(10 + formattedText.Width + 10, 0))!;
 
             context.DrawGeometry(null, new ImmutablePen(gradient.ToImmutable(), 2), highlightGeometry);
         }

samples/RenderDemo/Pages/GlyphRunPage.xaml.cs

@@ -29,7 +29,7 @@ namespace RenderDemo.Pages
         private float _fontSize = 20;
         private int _direction = 10;
 
-        private DispatcherTimer _timer;
+        private DispatcherTimer? _timer;
 
         protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
         {
@@ -48,7 +48,7 @@ namespace RenderDemo.Pages
 
         protected override void OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs e)
         {
-            _timer.Stop();
+            _timer?.Stop();
 
             _timer = null;
         }
@@ -88,7 +88,7 @@ namespace RenderDemo.Pages
         private float _fontSize = 20;
         private int _direction = 10;
 
-        private DispatcherTimer _timer;
+        private DispatcherTimer? _timer;
 
         protected override void OnAttachedToVisualTree(VisualTreeAttachmentEventArgs e)
         {
@@ -107,7 +107,7 @@ namespace RenderDemo.Pages
 
         protected override void OnDetachedFromVisualTree(VisualTreeAttachmentEventArgs e)
         {
-            _timer.Stop();
+            _timer?.Stop();
 
             _timer = null;
         }

samples/RenderDemo/Pages/PathMeasurementPage.cs

@@ -14,7 +14,7 @@ namespace RenderDemo.Pages
             AffectsRender<PathMeasurementPage>(BoundsProperty);
         }
 
-        private RenderTargetBitmap _bitmap;
+        private RenderTargetBitmap? _bitmap;
 
         protected override void OnAttachedToLogicalTree(LogicalTreeAttachmentEventArgs e)
         {
@@ -24,7 +24,7 @@ namespace RenderDemo.Pages
 
         protected override void OnDetachedFromLogicalTree(LogicalTreeAttachmentEventArgs e)
         {
-            _bitmap.Dispose();
+            _bitmap?.Dispose();
             _bitmap = null;
             base.OnDetachedFromLogicalTree(e);
         }
@@ -37,6 +37,9 @@ namespace RenderDemo.Pages
 
         public override void Render(DrawingContext context)
         {
+            if (_bitmap is null)
+                return;
+
             using (var bitmapCtx = _bitmap.CreateDrawingContext())
             {
                 var basePath = new PathGeometry();

samples/RenderDemo/Pages/RenderTargetBitmapPage.cs

@@ -10,7 +10,7 @@ namespace RenderDemo.Pages
 {
     public class RenderTargetBitmapPage : Control
     {
-        private RenderTargetBitmap _bitmap;
+        private RenderTargetBitmap? _bitmap;
 
         protected override void OnAttachedToLogicalTree(LogicalTreeAttachmentEventArgs e)
         {
@@ -20,7 +20,7 @@ namespace RenderDemo.Pages
 
         protected override void OnDetachedFromLogicalTree(LogicalTreeAttachmentEventArgs e)
         {
-            _bitmap.Dispose();
+            _bitmap?.Dispose();
             _bitmap = null;
             base.OnDetachedFromLogicalTree(e);
         }
@@ -28,6 +28,9 @@ namespace RenderDemo.Pages
         readonly Stopwatch _st = Stopwatch.StartNew();
         public override void Render(DrawingContext context)
         {
+            if (_bitmap is null)
+                return;
+
             using (var ctx = _bitmap.CreateDrawingContext())
             using (ctx.PushTransform(Matrix.CreateTranslation(-100, -100)
                                          * Matrix.CreateRotation(_st.Elapsed.TotalSeconds)

samples/RenderDemo/Pages/TextFormatterPage.axaml.cs

@@ -9,7 +9,7 @@ namespace RenderDemo.Pages
 {
     public class TextFormatterPage : UserControl
     {
-        private TextLine _textLine;
+        private TextLine? _textLine;
         
         public TextFormatterPage()
         {
@@ -50,7 +50,7 @@ namespace RenderDemo.Pages
         {
             var currentX = 0d;
             
-            foreach (var textRun in _textLine.TextRuns)
+            foreach (var textRun in _textLine?.TextRuns ?? [])
             {
                 if (textRun is ControlRun controlRun)
                 {
@@ -78,7 +78,7 @@ namespace RenderDemo.Pages
                 _defaultProperties = defaultProperties;
             }
             
-            public TextRun GetTextRun(int textSourceIndex)
+            public TextRun? GetTextRun(int textSourceIndex)
             {
                 if (textSourceIndex >= _text.Length * 2 + TextRun.DefaultTextSourceLength)
                 {

samples/RenderDemo/Pages/WriteableBitmapPage.cs

@@ -13,8 +13,8 @@ namespace RenderDemo.Pages
 {
     public class WriteableBitmapPage : Control
     {
-        private WriteableBitmap _unpremulBitmap;
+        private WriteableBitmap? _unpremulBitmap;
-        private WriteableBitmap _premulBitmap;
+        private WriteableBitmap? _premulBitmap;
         private readonly Stopwatch _st = Stopwatch.StartNew();
 
         protected override void OnAttachedToLogicalTree(LogicalTreeAttachmentEventArgs e)
@@ -38,6 +38,9 @@ namespace RenderDemo.Pages
 
         public override void Render(DrawingContext context)
         {
+            if (_unpremulBitmap is null || _premulBitmap is null)
+                return;
+
             void FillPixels(WriteableBitmap bitmap, byte fillAlpha, bool premul)
             {
                 using (var fb = bitmap.Lock())

samples/SafeAreaDemo.Android/SafeAreaDemo.Android.csproj

@@ -3,7 +3,6 @@
     <OutputType>Exe</OutputType>
     <TargetFramework>$(AvsCurrentAndroidTargetFramework)</TargetFramework>
     <SupportedOSPlatformVersion>$(AvsMinSupportedAndroidVersion)</SupportedOSPlatformVersion>
-    <Nullable>enable</Nullable>
     <ApplicationId>com.avalonia.safeareademo</ApplicationId>
     <ApplicationVersion>1</ApplicationVersion>
     <ApplicationDisplayVersion>1.0</ApplicationDisplayVersion>

samples/SafeAreaDemo.Desktop/SafeAreaDemo.Desktop.csproj

@@ -2,7 +2,6 @@
   <PropertyGroup>
     <OutputType>WinExe</OutputType>
     <TargetFramework>$(AvsCurrentTargetFramework)</TargetFramework>
-    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <PropertyGroup>

samples/SafeAreaDemo.iOS/SafeAreaDemo.iOS.csproj

@@ -4,7 +4,6 @@
     <TargetFramework>$(AvsCurrentIOSTargetFramework)</TargetFramework>
     <SupportedOSPlatformVersion>$(AvsMinSupportedIOSVersion)</SupportedOSPlatformVersion>
     <ProvisioningType>manual</ProvisioningType>
-    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/SafeAreaDemo/SafeAreaDemo.csproj

@@ -1,7 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <TargetFramework>$(AvsCurrentTargetFramework)</TargetFramework>
-    <Nullable>enable</Nullable>
     <AvaloniaUseCompiledBindingsByDefault>true</AvaloniaUseCompiledBindingsByDefault>
   </PropertyGroup>
 

samples/SampleControls/ControlSamples.csproj

@@ -2,7 +2,6 @@
 
   <PropertyGroup>
     <TargetFramework>$(AvsCurrentTargetFramework)</TargetFramework>
-    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/SingleProjectSandbox/SingleProjectSandbox.csproj

@@ -5,7 +5,6 @@
     <TargetFrameworks Condition="'$(IncludeMacTargetSamples)' == 'true'">$(TargetFrameworks);$(AvsCurrentMacOSTargetFramework)</TargetFrameworks>
     <OutputType>Exe</OutputType>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    <Nullable>enable</Nullable>
     <IncludeAvaloniaGenerators>true</IncludeAvaloniaGenerators>
   </PropertyGroup>
 

samples/TextTestApp/TextTestApp.csproj

@@ -6,7 +6,6 @@
     <TargetLatestRuntimePatch>true</TargetLatestRuntimePatch>
     <ApplicationManifest>app.manifest</ApplicationManifest>
     <IncludeAvaloniaGenerators>true</IncludeAvaloniaGenerators>
-    <Nullable>enable</Nullable>
   </PropertyGroup>
 
   <ItemGroup>

samples/UnloadableAssemblyLoadContext/UnloadableAssemblyLoadContext/UnloadableAssemblyLoadContext.csproj

@@ -3,7 +3,6 @@
   <PropertyGroup>
     <OutputType>WinExe</OutputType>
     <TargetFramework>$(AvsCurrentTargetFramework)</TargetFramework>
-    <Nullable>enable</Nullable>
     <BuiltInComInteropSupport>true</BuiltInComInteropSupport>
     <ApplicationManifest>app.manifest</ApplicationManifest>
     <AvaloniaUseCompiledBindingsByDefault>true</AvaloniaUseCompiledBindingsByDefault>

samples/UnloadableAssemblyLoadContext/UnloadableAssemblyLoadContextPlug/UnloadableAssemblyLoadContextPlug.csproj

@@ -2,7 +2,6 @@
 
   <PropertyGroup>
     <TargetFramework>$(AvsCurrentTargetFramework)</TargetFramework>
-    <Nullable>enable</Nullable>
     <BuiltInComInteropSupport>true</BuiltInComInteropSupport>
     <ApplicationManifest>app.manifest</ApplicationManifest>
     <AvaloniaUseCompiledBindingsByDefault>true</AvaloniaUseCompiledBindingsByDefault>

samples/XEmbedSample/XEmbedSample.csproj

@@ -4,16 +4,8 @@
     <OutputType>Exe</OutputType>
     <TargetFramework>$(AvsCurrentTargetFramework)</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
-    <Nullable>enable</Nullable>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
   </PropertyGroup>
-    <PropertyGroup>
-        <OutputType>Exe</OutputType>
-        <TargetFramework>$(AvsCurrentTargetFramework)</TargetFramework>
-        <ImplicitUsings>enable</ImplicitUsings>
-        <Nullable>enable</Nullable>
-        <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
-    </PropertyGroup>
 
   <ItemGroup>
     <PackageReference Include="GtkSharp" Version="3.24.24.95"/>

src/Headless/Avalonia.Headless.Vnc/HeadlessVncPlatformExtensions.cs

@@ -26,7 +26,7 @@ namespace Avalonia
         /// <returns></returns>
         public static int StartWithHeadlessVncPlatform(
             this AppBuilder builder,
-            string host, int port,
+            string? host, int port,
             string[] args,
             ShutdownMode shutdownMode = ShutdownMode.OnLastWindowClose)
         {
@@ -46,7 +46,7 @@ namespace Avalonia
         /// <exception cref="InvalidOperationException"></exception>
         public static int StartWithHeadlessVncPlatform(
             this AppBuilder builder,
-            string host, int port,
+            string? host, int port,
             string? password,
             string[] args,
             ShutdownMode shutdownMode = ShutdownMode.OnLastWindowClose)