The app crashes when the CallWindowProc function is used

[MGGSK]

Describe the bug

The app crashes when the window receives a message. The thrown exception is a System.ExecutionEngineException. It can't be catched using a try block or the App.UnhandledException event. Visual Studio shows that the call to "CallWindowProc" caused the exception (As seen in the screenshot).

Steps to reproduce the bug

1. Override the default window procedure (IntPtr oldWndProc = SetWindowLongPtr(hWnd, -4, CustomWindowProc);)
2. Call the window procedure that is build into WinUI (CallWindowProc(oldWndProc , hWnd, msg, wParam, lParam);)

Expected behavior

The window should have a minimum size and all other messages should be handled by WinUI.

Screenshots

NuGet package version

WinUI 3 - Windows App SDK 1.6.1: 1.6.240923002

Windows version

Windows 11 (22H2): Build 22621

Additional context

The code from my app:

IntPtr oldWndProc = IntPtr.Zero;
void RegisterWindowMessageHandler()
    => oldWndProc = User32.SetWindowLongPtr(hWnd, -4, NewWindowProc);

private IntPtr NewWindowProc(IntPtr hWnd, uint msg, IntPtr wParam, IntPtr lParam)
{
    switch (msg)
    {
        case WM_GETMINMAXINFO:
            var minMaxInfo = Marshal.PtrToStructure<MINMAXINFO>(lParam);
            minMaxInfo.ptMinTrackSize.X = minWidth; // Minimum width
            minMaxInfo.ptMinTrackSize.Y = minHeight; // Minimum height
            Marshal.StructureToPtr(minMaxInfo, lParam, true);
            break;

        default:
            break;
    }

    return User32.CallWindowProc(oldWndProc , hWnd, msg, wParam, lParam);
}

[castorix]

You must use

private delegate IntPtr WinProc(IntPtr hWnd, PInvoke.User32.WindowMessage Msg, IntPtr wParam, IntPtr lParam);
private WinProc newWndProc = null;
newWndProc = new WinProc(NewWindowProc);

like in this thread
(but MS recommends SetWindowSubclass (more recent))

[MGGSK]

You must use

private delegate IntPtr WinProc(IntPtr hWnd, PInvoke.User32.WindowMessage Msg, IntPtr wParam, IntPtr lParam);
private WinProc newWndProc = null;
newWndProc = new WinProc(NewWindowProc);

like in this thread (but MS recommends SetWindowSubclass (more recent))

That fixed it.