Nullable annotation for System.Windows.Extensions (#57896)

* Enable nullable in project file.

* Annotate SoundPlayer

* Annotate remaining types

* Update ref source

* Events should be nullable

* Fix assertion for NRE

* Update nullability of SoundLocation.

* Adjust nullability of SoundLocation and Stream.

* Title and message should be nullable

* Fix new NRT issue

src/libraries/Common/src/Interop/Windows/CryptUI/Interop.CryptUIDlgCertificate.cs

@@ -15,7 +15,7 @@ internal sealed class CRYPTUI_VIEWCERTIFICATE_STRUCTW
             internal uint dwSize;
             internal IntPtr hwndParent;
             internal uint dwFlags;
-            internal string szTitle;
+            internal string? szTitle;
             internal IntPtr pCertContext;
             internal IntPtr rgszPurposes;
             internal uint cPurposes;
@@ -38,9 +38,9 @@ internal sealed class CRYPTUI_SELECTCERTIFICATE_STRUCTW
             internal uint dwSize;
             internal IntPtr hwndParent;
             internal uint dwFlags;
-            internal string szTitle;
+            internal string? szTitle;
             internal uint dwDontUseColumn;
-            internal string szDisplayString;
+            internal string? szDisplayString;
             internal IntPtr pFilterCallback;
             internal IntPtr pDisplayCallback;
             internal IntPtr pvCallbackData;

src/libraries/Common/src/Interop/Windows/WinMm/Interop.PlaySound.cs

@@ -21,6 +21,6 @@ internal static partial class WinMM
         internal static partial bool PlaySound(string soundName, IntPtr hmod, int soundFlags);
 
         [GeneratedDllImport(Libraries.WinMM, EntryPoint = "PlaySoundW", ExactSpelling = true)]
-        internal static partial bool PlaySound(byte[] soundName, IntPtr hmod, int soundFlags);
+        internal static partial bool PlaySound(byte[]? soundName, IntPtr hmod, int soundFlags);
     }
 }

src/libraries/System.Windows.Extensions/ref/System.Windows.Extensions.cs

@@ -10,17 +10,17 @@ namespace System.Media
     public partial class SoundPlayer : System.ComponentModel.Component, System.Runtime.Serialization.ISerializable
     {
         public SoundPlayer() { }
-        public SoundPlayer(System.IO.Stream stream) { }
+        public SoundPlayer(System.IO.Stream? stream) { }
         protected SoundPlayer(System.Runtime.Serialization.SerializationInfo serializationInfo, System.Runtime.Serialization.StreamingContext context) { }
         public SoundPlayer(string soundLocation) { }
         public bool IsLoadCompleted { get { throw null; } }
         public int LoadTimeout { get { throw null; } set { } }
         public string SoundLocation { get { throw null; } set { } }
-        public System.IO.Stream Stream { get { throw null; } set { } }
-        public object Tag { get { throw null; } set { } }
-        public event System.ComponentModel.AsyncCompletedEventHandler LoadCompleted { add { } remove { } }
-        public event System.EventHandler SoundLocationChanged { add { } remove { } }
-        public event System.EventHandler StreamChanged { add { } remove { } }
+        public System.IO.Stream? Stream { get { throw null; } set { } }
+        public object? Tag { get { throw null; } set { } }
+        public event System.ComponentModel.AsyncCompletedEventHandler? LoadCompleted { add { } remove { } }
+        public event System.EventHandler? SoundLocationChanged { add { } remove { } }
+        public event System.EventHandler? StreamChanged { add { } remove { } }
         public void Load() { }
         public void LoadAsync() { }
         protected virtual void OnLoadCompleted(System.ComponentModel.AsyncCompletedEventArgs e) { }
@@ -53,8 +53,8 @@ public sealed partial class X509Certificate2UI
         public X509Certificate2UI() { }
         public static void DisplayCertificate(System.Security.Cryptography.X509Certificates.X509Certificate2 certificate) { }
         public static void DisplayCertificate(System.Security.Cryptography.X509Certificates.X509Certificate2 certificate, System.IntPtr hwndParent) { }
-        public static System.Security.Cryptography.X509Certificates.X509Certificate2Collection SelectFromCollection(System.Security.Cryptography.X509Certificates.X509Certificate2Collection certificates, string title, string message, System.Security.Cryptography.X509Certificates.X509SelectionFlag selectionFlag) { throw null; }
-        public static System.Security.Cryptography.X509Certificates.X509Certificate2Collection SelectFromCollection(System.Security.Cryptography.X509Certificates.X509Certificate2Collection certificates, string title, string message, System.Security.Cryptography.X509Certificates.X509SelectionFlag selectionFlag, System.IntPtr hwndParent) { throw null; }
+        public static System.Security.Cryptography.X509Certificates.X509Certificate2Collection SelectFromCollection(System.Security.Cryptography.X509Certificates.X509Certificate2Collection certificates, string? title, string? message, System.Security.Cryptography.X509Certificates.X509SelectionFlag selectionFlag) { throw null; }
+        public static System.Security.Cryptography.X509Certificates.X509Certificate2Collection SelectFromCollection(System.Security.Cryptography.X509Certificates.X509Certificate2Collection certificates, string? title, string? message, System.Security.Cryptography.X509Certificates.X509SelectionFlag selectionFlag, System.IntPtr hwndParent) { throw null; }
     }
     public enum X509SelectionFlag
     {
@@ -68,7 +68,7 @@ public partial class XamlAccessLevel
     {
         internal XamlAccessLevel() { }
         public System.Reflection.AssemblyName AssemblyAccessToAssemblyName { get { throw null; } }
-        public string PrivateAccessToTypeName { get { throw null; } }
+        public string? PrivateAccessToTypeName { get { throw null; } }
         public static System.Xaml.Permissions.XamlAccessLevel AssemblyAccessTo(System.Reflection.Assembly assembly) { throw null; }
         public static System.Xaml.Permissions.XamlAccessLevel AssemblyAccessTo(System.Reflection.AssemblyName assemblyName) { throw null; }
         public static System.Xaml.Permissions.XamlAccessLevel PrivateAccessTo(string assemblyQualifiedTypeName) { throw null; }

src/libraries/System.Windows.Extensions/ref/System.Windows.Extensions.csproj

@@ -1,6 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
     <TargetFrameworks>$(NetCoreAppCurrent);$(NetCoreAppMinimum)</TargetFrameworks>
+    <Nullable>enable</Nullable>
   </PropertyGroup>
   <ItemGroup>
     <Compile Include="System.Windows.Extensions.cs" />

src/libraries/System.Windows.Extensions/src/System.Windows.Extensions.csproj

@@ -3,6 +3,7 @@
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <Nullable>annotations</Nullable>
     <TargetFrameworks>$(NetCoreAppCurrent)-windows;$(NetCoreAppCurrent);$(NetCoreAppMinimum)-windows;$(NetCoreAppMinimum)</TargetFrameworks>
+    <Nullable>enable</Nullable>
     <IsPackable>true</IsPackable>
     <PackageDescription>Provides miscellaneous Windows-specific types
 

src/libraries/System.Windows.Extensions/src/System/Media/SoundPlayer.cs

@@ -3,6 +3,7 @@
 
 using System.ComponentModel;
 using System.Diagnostics;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Net;
 using System.Runtime.InteropServices;
@@ -18,7 +19,7 @@ public class SoundPlayer : Component, ISerializable
         private const int BlockSize = 1024;
         private const int DefaultLoadTimeout = 10000; // 10 secs
 
-        private Uri _uri;
+        private Uri? _uri;
         private string _soundLocation = string.Empty;
         private int _loadTimeout = DefaultLoadTimeout;
 
@@ -28,16 +29,16 @@ public class SoundPlayer : Component, ISerializable
         // the worker copyTask
         // we start the worker copyTask ONLY from entry points in the SoundPlayer API
         // we also set the tread to null only from the entry points in the SoundPlayer API
-        private Task _copyTask;
-        private CancellationTokenSource _copyTaskCancellation;
+        private Task? _copyTask;
+        private CancellationTokenSource? _copyTaskCancellation;
 
         // local buffer information
         private int _currentPos;
-        private Stream _stream;
-        private Exception _lastLoadException;
+        private Stream? _stream;
+        private Exception? _lastLoadException;
         private bool _doesLoadAppearSynchronous;
-        private byte[] _streamData;
-        private AsyncOperation _asyncOperation;
+        private byte[]? _streamData;
+        private AsyncOperation? _asyncOperation;
         private readonly SendOrPostCallback _loadAsyncOperationCompleted;
 
         // event
@@ -55,7 +56,7 @@ public SoundPlayer(string soundLocation) : this()
             SetupSoundLocation(soundLocation ?? string.Empty);
         }
 
-        public SoundPlayer(Stream stream) : this()
+        public SoundPlayer(Stream? stream) : this()
         {
             _stream = stream;
         }
@@ -99,7 +100,7 @@ public string SoundLocation
             }
         }
 
-        public Stream Stream
+        public Stream? Stream
         {
             get
             {
@@ -126,7 +127,7 @@ public Stream Stream
 
         public bool IsLoadCompleted { get; private set; }
 
-        public object Tag { get; set; }
+        public object? Tag { get; set; }
 
         public void LoadAsync()
         {
@@ -161,9 +162,9 @@ public void LoadAsync()
             LoadStream(false);
         }
 
-        private void LoadAsyncOperationCompleted(object arg)
+        private void LoadAsyncOperationCompleted(object? arg)
         {
-            OnLoadCompleted((AsyncCompletedEventArgs)arg);
+            OnLoadCompleted((AsyncCompletedEventArgs)arg!);
         }
 
         // called for loading a stream synchronously
@@ -227,6 +228,7 @@ private void LoadAndPlay(int flags)
             else
             {
                 LoadSync();
+                Debug.Assert(_streamData != null);
                 ValidateSoundData(_streamData);
                 Interop.WinMM.PlaySound(_streamData, IntPtr.Zero, Interop.WinMM.SND_MEMORY | Interop.WinMM.SND_NODEFAULT | flags);
             }
@@ -271,7 +273,9 @@ private void LoadSync()
                 _stream = webResponse.GetResponseStream();
             }
 
-            if (_stream.CanSeek)
+            // DO NOT assert - NRE is expected for null stream
+            // See SoundPlayerTests.Load_NullStream_ThrowsNullReferenceException
+            if (_stream!.CanSeek)
             {
                 // if we can get data synchronously, then get it
                 LoadStream(true);
@@ -304,6 +308,7 @@ private void LoadSync()
 
         private void LoadStream(bool loadSync)
         {
+            Debug.Assert(_stream != null);
             if (loadSync && _stream.CanSeek)
             {
                 int streamLen = (int)_stream.Length;
@@ -339,9 +344,9 @@ public void PlayLooping()
             LoadAndPlay(Interop.WinMM.SND_LOOP | Interop.WinMM.SND_ASYNC);
         }
 
-        private static Uri ResolveUri(string partialUri)
+        private static Uri? ResolveUri(string partialUri)
         {
-            Uri result = null;
+            Uri? result = null;
             try
             {
                 result = new Uri(partialUri);
@@ -399,7 +404,7 @@ private void SetupSoundLocation(string soundLocation)
             }
         }
 
-        private void SetupStream(Stream stream)
+        private void SetupStream(Stream? stream)
         {
             if (_copyTask != null)
             {
@@ -420,10 +425,10 @@ private void SetupStream(Stream stream)
 
         public void Stop()
         {
-            Interop.WinMM.PlaySound((byte[])null, IntPtr.Zero, Interop.WinMM.SND_PURGE);
+            Interop.WinMM.PlaySound((byte[]?)null, IntPtr.Zero, Interop.WinMM.SND_PURGE);
         }
 
-        public event AsyncCompletedEventHandler LoadCompleted
+        public event AsyncCompletedEventHandler? LoadCompleted
         {
             add
             {
@@ -435,7 +440,7 @@ public event AsyncCompletedEventHandler LoadCompleted
             }
         }
 
-        public event EventHandler SoundLocationChanged
+        public event EventHandler? SoundLocationChanged
         {
             add
             {
@@ -447,7 +452,7 @@ public event EventHandler SoundLocationChanged
             }
         }
 
-        public event EventHandler StreamChanged
+        public event EventHandler? StreamChanged
         {
             add
             {
@@ -461,22 +466,22 @@ public event EventHandler StreamChanged
 
         protected virtual void OnLoadCompleted(AsyncCompletedEventArgs e)
         {
-            ((AsyncCompletedEventHandler)Events[s_eventLoadCompleted])?.Invoke(this, e);
+            ((AsyncCompletedEventHandler?)Events[s_eventLoadCompleted])?.Invoke(this, e);
         }
 
         protected virtual void OnSoundLocationChanged(EventArgs e)
         {
-            ((EventHandler)Events[s_eventSoundLocationChanged])?.Invoke(this, e);
+            ((EventHandler?)Events[s_eventSoundLocationChanged])?.Invoke(this, e);
         }
 
         protected virtual void OnStreamChanged(EventArgs e)
         {
-            ((EventHandler)Events[s_eventStreamChanged])?.Invoke(this, e);
+            ((EventHandler?)Events[s_eventStreamChanged])?.Invoke(this, e);
         }
 
         private async Task CopyStreamAsync(CancellationToken cancellationToken)
         {
-            Exception exception = null;
+            Exception? exception = null;
             try
             {
                 // setup the http stream
@@ -485,7 +490,7 @@ private async Task CopyStreamAsync(CancellationToken cancellationToken)
 #pragma warning disable SYSLIB0014 // WebRequest, HttpWebRequest, ServicePoint, and WebClient are obsolete. Use HttpClient instead.
                     WebRequest webRequest = WebRequest.Create(_uri);
 #pragma warning restore SYSLIB0014
-                    using (cancellationToken.Register(r => ((WebRequest)r).Abort(), webRequest))
+                    using (cancellationToken.Register(r => ((WebRequest)r!).Abort(), webRequest))
                     {
                         WebResponse webResponse = await webRequest.GetResponseAsync().ConfigureAwait(false);
                         _stream = webResponse.GetResponseStream();
@@ -494,6 +499,7 @@ private async Task CopyStreamAsync(CancellationToken cancellationToken)
 
                 _streamData = new byte[BlockSize];
 
+                Debug.Assert(_stream != null);
                 int readBytes = await _stream.ReadAsync(_streamData.AsMemory(_currentPos, BlockSize), cancellationToken).ConfigureAwait(false);
                 int totalBytes = readBytes;
 
@@ -525,6 +531,7 @@ private async Task CopyStreamAsync(CancellationToken cancellationToken)
                 AsyncCompletedEventArgs ea = exception is OperationCanceledException ?
                     new AsyncCompletedEventArgs(null, cancelled: true, null) :
                     new AsyncCompletedEventArgs(exception, cancelled: false, null);
+                Debug.Assert(_asyncOperation != null);
                 _asyncOperation.PostOperationCompleted(_loadAsyncOperationCompleted, ea);
             }
         }
@@ -539,7 +546,7 @@ private unsafe void ValidateSoundFile(string fileName)
 
             try
             {
-                Interop.WinMM.WAVEFORMATEX waveFormat = null;
+                Interop.WinMM.WAVEFORMATEX? waveFormat = null;
                 var ckRIFF = new Interop.WinMM.MMCKINFO()
                 {
                     fccType = mmioFOURCC('W', 'A', 'V', 'E')

src/libraries/System.Windows.Extensions/src/System/Media/SystemSounds.cs

@@ -5,11 +5,11 @@ namespace System.Media
 {
     public static class SystemSounds
     {
-        private static volatile SystemSound s_asterisk;
-        private static volatile SystemSound s_beep;
-        private static volatile SystemSound s_exclamation;
-        private static volatile SystemSound s_hand;
-        private static volatile SystemSound s_question;
+        private static volatile SystemSound? s_asterisk;
+        private static volatile SystemSound? s_beep;
+        private static volatile SystemSound? s_exclamation;
+        private static volatile SystemSound? s_hand;
+        private static volatile SystemSound? s_question;
 
         public static SystemSound Asterisk
         {

src/libraries/System.Windows.Extensions/src/System/Security/Cryptography/X509Certificates/X509Certificate2UI.cs

@@ -31,12 +31,12 @@ public static void DisplayCertificate(X509Certificate2 certificate, IntPtr hwndP
             DisplayX509Certificate(certificate, hwndParent);
         }
 
-        public static X509Certificate2Collection SelectFromCollection(X509Certificate2Collection certificates, string title, string message, X509SelectionFlag selectionFlag)
+        public static X509Certificate2Collection SelectFromCollection(X509Certificate2Collection certificates, string? title, string? message, X509SelectionFlag selectionFlag)
         {
             return SelectFromCollectionHelper(certificates, title, message, selectionFlag, IntPtr.Zero);
         }
 
-        public static X509Certificate2Collection SelectFromCollection(X509Certificate2Collection certificates, string title, string message, X509SelectionFlag selectionFlag, IntPtr hwndParent)
+        public static X509Certificate2Collection SelectFromCollection(X509Certificate2Collection certificates, string? title, string? message, X509SelectionFlag selectionFlag, IntPtr hwndParent)
         {
             return SelectFromCollectionHelper(certificates, title, message, selectionFlag, hwndParent);
         }
@@ -82,7 +82,7 @@ private static void DisplayX509Certificate(X509Certificate2 certificate, IntPtr
             }
         }
 
-        private static X509Certificate2Collection SelectFromCollectionHelper(X509Certificate2Collection certificates, string title, string message, X509SelectionFlag selectionFlag, IntPtr hwndParent)
+        private static X509Certificate2Collection SelectFromCollectionHelper(X509Certificate2Collection certificates, string? title, string? message, X509SelectionFlag selectionFlag, IntPtr hwndParent)
         {
             if (certificates == null)
                 throw new ArgumentNullException(nameof(certificates));
@@ -96,7 +96,7 @@ private static X509Certificate2Collection SelectFromCollectionHelper(X509Certifi
             }
         }
 
-        private static unsafe SafeCertStoreHandle SelectFromStore(SafeCertStoreHandle safeSourceStoreHandle, string title, string message, X509SelectionFlag selectionFlags, IntPtr hwndParent)
+        private static unsafe SafeCertStoreHandle SelectFromStore(SafeCertStoreHandle safeSourceStoreHandle, string? title, string? message, X509SelectionFlag selectionFlags, IntPtr hwndParent)
         {
             int dwErrorCode = ERROR_SUCCESS;
 

src/libraries/System.Windows.Extensions/src/System/Xaml/Permissions/XamlAccessLevel.cs

@@ -8,15 +8,15 @@ namespace System.Xaml.Permissions
 {
     public class XamlAccessLevel
     {
-        private XamlAccessLevel(string assemblyName, string typeName)
+        private XamlAccessLevel(string assemblyName, string? typeName)
         {
             AssemblyNameString = assemblyName;
             PrivateAccessToTypeName = typeName;
         }
 
         public static XamlAccessLevel AssemblyAccessTo(Assembly assembly)
         {
-            return new XamlAccessLevel(assembly.FullName, null);
+            return new XamlAccessLevel(assembly.FullName!, null);
         }
 
         public static XamlAccessLevel AssemblyAccessTo(AssemblyName assemblyName)
@@ -26,7 +26,7 @@ public static XamlAccessLevel AssemblyAccessTo(AssemblyName assemblyName)
 
         public static XamlAccessLevel PrivateAccessTo(Type type)
         {
-            return new XamlAccessLevel(type.Assembly.FullName, type.FullName);
+            return new XamlAccessLevel(type.Assembly.FullName!, type.FullName);
         }
 
         public static XamlAccessLevel PrivateAccessTo(string assemblyQualifiedTypeName)
@@ -43,7 +43,7 @@ public AssemblyName AssemblyAccessToAssemblyName
             get { return new AssemblyName(AssemblyNameString); }
         }
 
-        public string PrivateAccessToTypeName { get; private set; }
+        public string? PrivateAccessToTypeName { get; private set; }
 
         internal string AssemblyNameString { get; private set; }
     }