From f23ac13c853ef3d2c864cd7e6f934f539f9bc710 Mon Sep 17 00:00:00 2001
From: Loni Tra <lonitra@microsoft.com>
Date: Tue, 19 Nov 2024 14:20:34 -0800
Subject: [PATCH] Call correct HtmlHelp overload

---
 .../src/NativeMethods.txt                      |  1 +
 .../src/Windows/Win32/PInvoke.HtmlHelp.cs      | 18 ++++++------------
 .../src/System/Windows/Forms/Help/Help.cs      |  2 +-
 3 files changed, 8 insertions(+), 13 deletions(-)

diff --git a/src/System.Windows.Forms.Primitives/src/NativeMethods.txt b/src/System.Windows.Forms.Primitives/src/NativeMethods.txt
index 3947d715d06..5df70140251 100644
--- a/src/System.Windows.Forms.Primitives/src/NativeMethods.txt
+++ b/src/System.Windows.Forms.Primitives/src/NativeMethods.txt
@@ -259,6 +259,7 @@ HideCaret
 HitTestThemeBackground
 HT*
 HTML_HELP_COMMAND
+HtmlHelp
 HTREEITEM
 IAccessible
 IAccessibleEx
diff --git a/src/System.Windows.Forms.Primitives/src/Windows/Win32/PInvoke.HtmlHelp.cs b/src/System.Windows.Forms.Primitives/src/Windows/Win32/PInvoke.HtmlHelp.cs
index 9d8002e41e8..46415728261 100644
--- a/src/System.Windows.Forms.Primitives/src/Windows/Win32/PInvoke.HtmlHelp.cs
+++ b/src/System.Windows.Forms.Primitives/src/Windows/Win32/PInvoke.HtmlHelp.cs
@@ -1,25 +1,19 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System.Runtime.InteropServices;
 using Windows.Win32.Data.HtmlHelp;
 
 namespace Windows.Win32;
 
 internal static partial class PInvoke
 {
-    internal static unsafe HWND HtmlHelp(HWND hwndCaller, string? pszFile, HTML_HELP_COMMAND uCommand, nuint dwData)
+    /// <inheritdoc cref="HtmlHelp(HWND, string, HTML_HELP_COMMAND, nuint)" />
+    internal static unsafe HWND HtmlHelp<T>(T hwndCaller, string? pszFile, HTML_HELP_COMMAND uCommand, nuint dwData)
+        where T : IHandle<HWND>
     {
-        // Copied from generated code pending resolution of https://github.com/microsoft/win32metadata/issues/1749
-
-        fixed (char* p = pszFile)
-        {
-            HWND __retVal = LocalExternFunction(hwndCaller, p, (uint)uCommand, dwData);
-            return __retVal;
-        }
-
-        [DllImport(Libraries.Hhctrl, ExactSpelling = true, EntryPoint = "HtmlHelpW")]
-        static extern HWND LocalExternFunction(HWND hwndCaller, PCWSTR pszFile, uint uCommand, nuint dwData);
+        HWND result = HtmlHelp(hwndCaller.Handle, pszFile, uCommand, dwData);
+        GC.KeepAlive(hwndCaller.Wrapper);
+        return result;
     }
 
     /// <inheritdoc cref="HtmlHelp(HWND, string, HTML_HELP_COMMAND, nuint)" />
diff --git a/src/System.Windows.Forms/src/System/Windows/Forms/Help/Help.cs b/src/System.Windows.Forms/src/System/Windows/Forms/Help/Help.cs
index 3cd518d89d8..445bf395138 100644
--- a/src/System.Windows.Forms/src/System/Windows/Forms/Help/Help.cs
+++ b/src/System.Windows.Forms/src/System/Windows/Forms/Help/Help.cs
@@ -146,7 +146,7 @@ private static unsafe void ShowHTML10Help(Control? parent, string? url, HelpNavi
             }
             else if (htmlParam is int intParam)
             {
-                PInvoke.HtmlHelp(handle, pathAndFileName, htmlCommand, in intParam);
+                PInvoke.HtmlHelp(handle, pathAndFileName, htmlCommand, (nuint)intParam);
             }
             else if (htmlParam is HH_FTS_QUERY query)
             {