Enable nullable reference types for System.Windows.Forms.Primitives

src/System.Windows.Forms.Primitives/src/Interop/ComCtl32/Interop.TTOOLINFOW.cs

@@ -3,6 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.Runtime.InteropServices;
 
 internal static partial class Interop
@@ -27,10 +28,11 @@ public struct ToolInfoWrapper<T>
             where T : IHandle
         {
             public TTOOLINFOW Info;
-            public string Text { get; set; }
+            public string? Text { get; set; }
+            [MaybeNull]
             private readonly T _handle;
 
-            public unsafe ToolInfoWrapper(T handle, TTF flags = default, string text = null)
+            public unsafe ToolInfoWrapper(T handle, TTF flags = default, string? text = null)
             {
                 Info = new TTOOLINFOW
                 {
@@ -42,7 +44,7 @@ public unsafe ToolInfoWrapper(T handle, TTF flags = default, string text = null)
                 _handle = handle;
             }
 
-            public unsafe ToolInfoWrapper(T handle, IntPtr id, TTF flags = default, string text = null, RECT rect = default)
+            public unsafe ToolInfoWrapper(T handle, IntPtr id, TTF flags = default, string? text = null, RECT rect = default)
             {
                 Info = new TTOOLINFOW
                 {

src/System.Windows.Forms.Primitives/src/Interop/Gdi32/Interop.BITMAPINFO.cs

@@ -16,7 +16,7 @@ public struct BITMAPINFO
             public BITMAPINFOHEADER bmiHeader;
 
             [MarshalAs(UnmanagedType.ByValArray, SizeConst = MaxColorSize * 4)]
-            public byte[] bmiColors; // RGBQUAD structs: repeating Blue-Green-Red-Reserved
+            public byte[]? bmiColors; // RGBQUAD structs: repeating Blue-Green-Red-Reserved
         }
     }
 }

src/System.Windows.Forms.Primitives/src/Interop/Ole32/Interop.OLEVERB.cs

@@ -13,7 +13,7 @@ public class OLEVERB
         {
             public OLEIVERB lVerb;
             [MarshalAs(UnmanagedType.LPWStr)]
-            public string lpszVerbName;
+            public string? lpszVerbName;
             public User32.MF fuFlags;
             public OLEVERBATTRIB grfAttribs;
         }

src/System.Windows.Forms.Primitives/src/Interop/Ole32/Interop.QACONTAINER.cs

@@ -14,20 +14,20 @@ internal static partial class Ole32
         public sealed class QACONTAINER
         {
             public uint cbSize;
-            public IOleClientSite pClientSite;
-            public IAdviseSink pAdviseSink;
-            public IPropertyNotifySink pPropertyNotifySink;
+            public IOleClientSite? pClientSite;
+            public IAdviseSink? pAdviseSink;
+            public IPropertyNotifySink? pPropertyNotifySink;
             [MarshalAs(UnmanagedType.Interface)]
-            public object pUnkEventSink;
+            public object? pUnkEventSink;
             public QACONTAINERFLAGS dwAmbientFlags;
             public uint colorFore;
             public uint colorBack;
-            public IFont pFont;
+            public IFont? pFont;
             public IntPtr pUndoMgr;
             public uint dwAppearance;
             public int lcid;
             public IntPtr hpal;
-            public IServiceProvider pBindHost;
+            public IServiceProvider? pBindHost;
         }
     }
 }

src/System.Windows.Forms.Primitives/src/Interop/Ole32/Interop.STATSTG.cs

@@ -60,7 +60,7 @@ public struct STATSTG
             public uint grfStateBits;
             public uint reserved;
 
-            public string GetName() => Marshal.PtrToStringUni(pwcsName);
+            public string? GetName() => Marshal.PtrToStringUni(pwcsName);
 
             /// <summary>
             ///  Caller is responsible for freeing the name memory.
@@ -76,7 +76,7 @@ public void FreeName()
             /// <summary>
             ///  Callee is repsonsible for allocating the name memory.
             /// </summary>
-            public void AllocName(string name)
+            public void AllocName(string? name)
             {
                 pwcsName = Marshal.StringToCoTaskMemUni(name);
             }

src/System.Windows.Forms.Primitives/src/Interop/Ole32/Interop.VARIANT.cs

@@ -42,7 +42,7 @@ public void Clear()
 
             ~VARIANT() => Clear();
 
-            public object ToObject()
+            public object? ToObject()
             {
                 IntPtr val = data1;
                 long longVal;
@@ -165,8 +165,8 @@ public object ToObject()
                         return (val != IntPtr.Zero);
 
                     case VARENUM.VARIANT:
-                        VARIANT varStruct = Marshal.PtrToStructure<VARIANT>(val);
-                        return varStruct.ToObject();
+                        VARIANT? varStruct = Marshal.PtrToStructure<VARIANT>(val);
+                        return varStruct?.ToObject();
 
                     case VARENUM.CLSID:
                         Guid guid = Marshal.PtrToStructure<Guid>(val);

src/System.Windows.Forms.Primitives/src/Interop/OleAut32/Interop.FONTDESC.cs

@@ -13,7 +13,7 @@ internal static partial class Oleaut32
         public struct FONTDESC
         {
             public uint cbSizeOfStruct;
-            public string lpstrName;
+            public string? lpstrName;
             public long cySize;
             public short sWeight;
             public short sCharset;

src/System.Windows.Forms.Primitives/src/Interop/Shell32/Interop.DragQueryFileW.cs

@@ -11,7 +11,7 @@ internal static partial class Interop
     internal static partial class Shell32
     {
         [DllImport(Libraries.Shell32, ExactSpelling = true, EntryPoint = "DragQueryFileW", CharSet = CharSet.Unicode)]
-        private static extern uint DragQueryFileWInternal(IntPtr hDrop, uint iFile, StringBuilder lpszFile, uint cch);
+        private static extern uint DragQueryFileWInternal(IntPtr hDrop, uint iFile, StringBuilder? lpszFile, uint cch);
 
         public static uint DragQueryFileW(IntPtr hDrop, uint iFile, StringBuilder lpszFile)
         {

src/System.Windows.Forms.Primitives/src/Interop/Shell32/Interop.SHBrowseForFolder.cs

@@ -34,15 +34,15 @@ public unsafe struct BROWSEINFO
         {
             public IntPtr hwndOwner;
 
-            public CoTaskMemSafeHandle pidlRoot;
+            public CoTaskMemSafeHandle? pidlRoot;
 
             public char* pszDisplayName;
 
-            public string lpszTitle;
+            public string? lpszTitle;
 
             public uint ulFlags;
 
-            public BrowseCallbackProc lpfn;
+            public BrowseCallbackProc? lpfn;
 
             public IntPtr lParam;
 

src/System.Windows.Forms.Primitives/src/Interop/Shell32/Interop.SHGetPathFromIDListLongPath.cs

@@ -12,7 +12,7 @@ internal static partial class Shell32
         [DllImport(Libraries.Shell32, ExactSpelling = true)]
         private static extern BOOL SHGetPathFromIDListEx(IntPtr pidl, IntPtr pszPath, int cchPath, int flags);
 
-        public static bool SHGetPathFromIDListLongPath(IntPtr pidl, out string path)
+        public static bool SHGetPathFromIDListLongPath(IntPtr pidl, out string? path)
         {
             IntPtr pszPath = Marshal.AllocHGlobal((Kernel32.MAX_PATH + 1) * sizeof(char));
             int length = Kernel32.MAX_PATH;

src/System.Windows.Forms.Primitives/src/Interop/User32/Interop.DEVMODEW.cs

@@ -17,7 +17,7 @@ public struct DEVMODEW
             private const int CCHFORMNAME = 32;
 
             [MarshalAs(UnmanagedType.ByValTStr, SizeConst = CCHDEVICENAME)]
-            public string dmDeviceName;
+            public string? dmDeviceName;
             public ushort dmSpecVersion;
             public ushort dmDriverVersion;
             public ushort dmSize;
@@ -33,7 +33,7 @@ public struct DEVMODEW
             public short dmTTOption;
             public short dmCollate;
             [MarshalAs(UnmanagedType.ByValTStr, SizeConst = CCHFORMNAME)]
-            public string dmFormName;
+            public string? dmFormName;
             public ushort dmLogPixels;
             public uint dmBitsPerPel;
             public uint dmPelsWidth;

src/System.Windows.Forms.Primitives/src/Interop/User32/Interop.EnumChildWindows.cs

@@ -50,7 +50,7 @@ public static BOOL EnumChildWindows(HandleRef hwndParent, EnumChildWindowsCallba
 
         private static BOOL HandleEnumChildWindowsNativeCallback(IntPtr hWnd, IntPtr lParam)
         {
-            return ((EnumChildWindowsCallback)GCHandle.FromIntPtr(lParam).Target)(hWnd);
+            return ((EnumChildWindowsCallback)GCHandle.FromIntPtr(lParam).Target!)(hWnd);
         }
     }
 }

src/System.Windows.Forms.Primitives/src/Interop/User32/Interop.EnumThreadWindows.cs

@@ -36,7 +36,7 @@ public static BOOL EnumThreadWindows(uint dwThreadId, EnumThreadWindowsCallback
 
         private static BOOL HandleEnumThreadWindowsNativeCallback(IntPtr hWnd, IntPtr lParam)
         {
-            return ((EnumThreadWindowsCallback)GCHandle.FromIntPtr(lParam).Target)(hWnd);
+            return ((EnumThreadWindowsCallback)GCHandle.FromIntPtr(lParam).Target!)(hWnd);
         }
     }
 }

src/System.Windows.Forms.Primitives/src/Interop/User32/Interop.EnumWindows.cs

@@ -36,7 +36,7 @@ public static BOOL EnumWindows(EnumWindowsCallback lpEnumFunc)
 
         private static BOOL HandleEnumWindowsNativeCallback(IntPtr hWnd, IntPtr lParam)
         {
-            return ((EnumWindowsCallback)GCHandle.FromIntPtr(lParam).Target)(hWnd);
+            return ((EnumWindowsCallback)GCHandle.FromIntPtr(lParam).Target!)(hWnd);
         }
     }
 }

src/System.Windows.Forms.Primitives/src/Interop/User32/Interop.GetClipboardFormatNameW.cs

@@ -13,7 +13,7 @@ internal static partial class User32
         [DllImport(Libraries.User32, ExactSpelling = true)]
         private static unsafe extern int GetClipboardFormatNameW(uint format, char* lpszFormatName, int cchMaxCount);
 
-        public static unsafe string GetClipboardFormatNameW(uint format)
+        public static unsafe string? GetClipboardFormatNameW(uint format)
         {
             // The max length of the name of clipboard formats is equal to the max length
             // of a Win32 Atom of 255 chars. An additional null terminator character is added,

src/System.Windows.Forms.Primitives/src/System.Windows.Forms.Primitives.csproj

@@ -4,6 +4,7 @@
     <AssemblyName>System.Windows.Forms.Primitives</AssemblyName>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <CLSCompliant>true</CLSCompliant>
+    <Nullable>enable</Nullable>
     <!--the obsolete usage in public surface can't be removed-->
     <NoWarn>$(NoWarn);618</NoWarn>
     <Deterministic>true</Deterministic>

src/System.Windows.Forms.Primitives/src/System/ComponentModel/CompModSwitches.cs

@@ -8,39 +8,39 @@ namespace System.ComponentModel
 {
     internal static class CompModSwitches
     {
-        private static TraceSwitch activeX;
-        private static TraceSwitch flowLayout;
-        private static TraceSwitch dataCursor;
-        private static TraceSwitch dataGridCursor;
-        private static TraceSwitch dataGridEditing;
-        private static TraceSwitch dataGridKeys;
-        private static TraceSwitch dataGridLayout;
-        private static TraceSwitch dataGridPainting;
-        private static TraceSwitch dataGridParents;
-        private static TraceSwitch dataGridScrolling;
-        private static TraceSwitch dataGridSelection;
-        private static TraceSwitch dataObject;
-        private static TraceSwitch dataView;
-        private static TraceSwitch debugGridView;
-        private static TraceSwitch dgCaptionPaint;
-        private static TraceSwitch dgEditColumnEditing;
-        private static TraceSwitch dgRelationShpRowLayout;
-        private static TraceSwitch dgRelationShpRowPaint;
-        private static TraceSwitch dgRowPaint;
-        private static TraceSwitch dragDrop;
-        private static TraceSwitch imeMode;
-        private static TraceSwitch msaa;
-        private static TraceSwitch msoComponentManager;
-        private static TraceSwitch layoutPerformance;
-        private static TraceSwitch layoutSuspendResume;
-        private static TraceSwitch richLayout;
-        private static TraceSwitch setBounds;
-
-        private static BooleanSwitch lifetimeTracing;
-
-        private static TraceSwitch s_handleLeak;
-        private static BooleanSwitch s_traceCollect;
-        private static BooleanSwitch s_commonDesignerServices;
+        private static TraceSwitch? activeX;
+        private static TraceSwitch? flowLayout;
+        private static TraceSwitch? dataCursor;
+        private static TraceSwitch? dataGridCursor;
+        private static TraceSwitch? dataGridEditing;
+        private static TraceSwitch? dataGridKeys;
+        private static TraceSwitch? dataGridLayout;
+        private static TraceSwitch? dataGridPainting;
+        private static TraceSwitch? dataGridParents;
+        private static TraceSwitch? dataGridScrolling;
+        private static TraceSwitch? dataGridSelection;
+        private static TraceSwitch? dataObject;
+        private static TraceSwitch? dataView;
+        private static TraceSwitch? debugGridView;
+        private static TraceSwitch? dgCaptionPaint;
+        private static TraceSwitch? dgEditColumnEditing;
+        private static TraceSwitch? dgRelationShpRowLayout;
+        private static TraceSwitch? dgRelationShpRowPaint;
+        private static TraceSwitch? dgRowPaint;
+        private static TraceSwitch? dragDrop;
+        private static TraceSwitch? imeMode;
+        private static TraceSwitch? msaa;
+        private static TraceSwitch? msoComponentManager;
+        private static TraceSwitch? layoutPerformance;
+        private static TraceSwitch? layoutSuspendResume;
+        private static TraceSwitch? richLayout;
+        private static TraceSwitch? setBounds;
+
+        private static BooleanSwitch? lifetimeTracing;
+
+        private static TraceSwitch? s_handleLeak;
+        private static BooleanSwitch? s_traceCollect;
+        private static BooleanSwitch? s_commonDesignerServices;
 
         public static TraceSwitch ActiveX
         {

src/System.Windows.Forms.Primitives/src/System/Windows/Forms/FileDialogCustomPlace.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Diagnostics.CodeAnalysis;
 using static Interop;
 
 namespace System.Windows.Forms
@@ -18,7 +19,7 @@ public class FileDialogCustomPlace
         private string _path = string.Empty;
         private Guid _knownFolderGuid = Guid.Empty;
 
-        public FileDialogCustomPlace(string path)
+        public FileDialogCustomPlace(string? path)
         {
             Path = path;
         }
@@ -28,6 +29,7 @@ public FileDialogCustomPlace(Guid knownFolderGuid)
             KnownFolderGuid = knownFolderGuid;
         }
 
+        [AllowNull]
         public string Path
         {
             get => _path ?? string.Empty;
@@ -58,7 +60,7 @@ public override string ToString()
         ///  to an actual filesystem directory.
         ///  The caller is responsible for handling these situations.
         /// </remarks>
-        internal FileDialogNative.IShellItem GetNativePath()
+        internal FileDialogNative.IShellItem? GetNativePath()
         {
             string filePathString;
             if (!string.IsNullOrEmpty(_path))

src/System.Windows.Forms.Primitives/src/System/Windows/Forms/FileDialogCustomPlacesCollection.cs

@@ -18,7 +18,7 @@ internal void Apply(FileDialogNative.IFileDialog dialog)
 
                 try
                 {
-                    FileDialogNative.IShellItem shellItem = customPlace.GetNativePath();
+                    FileDialogNative.IShellItem? shellItem = customPlace.GetNativePath();
                     if (null != shellItem)
                     {
                         dialog.AddPlace(shellItem, 0);
@@ -32,7 +32,7 @@ internal void Apply(FileDialogNative.IFileDialog dialog)
             }
         }
 
-        public void Add(string path) => Add(new FileDialogCustomPlace(path));
+        public void Add(string? path) => Add(new FileDialogCustomPlace(path));
 
         public void Add(Guid knownFolderGuid) => Add(new FileDialogCustomPlace(knownFolderGuid));
     }