How Can I fix lParam pointer Error in Pinvoke/Win32 ?

Question

Hi there, currently I need to dig up some Win32 code which is a part of my project, Actually, it's a part of my WPF application where access Win32 APIs using the traditional Pinvoke method.

But Currently I facing some error at lParam pointer structure.

Here is the piece of code where I face the problem :

 MINMAXINFO mmi = (MINMAXINFO)Marshal.PtrToStructure(lParam, typeof(MINMAXINFO));
 if (monitor != IntPtr.Zero)
 {
     MONITORINFO monitorInfo = new MONITORINFO();
     GetMonitorInfo(monitor, monitorInfo);

I get red squiggly Line on MINMAXINFO and on MONITORINFO on my Visual Studio 2022.

I hope someone who frequently work with Win32 APIs will able to solve my problem.

Another important point is I already do the necessary DLL imports like

 [DllImport("user32" )]

Hope someone able to figure out my problem. I also attached some images for better visualization and better understanding of the problem.

Here is my Full source Code : https://pastebin.com/Y7puGMsZ

I gave the Pastebin link here because posting full source Code may filter by the moderator and bots.

I hope this Microsoft Q & A site content moderation will improve in future, because now a days people facing a lot of problems when they posting any question here, their post will automatically get deleted and comments are filtered and deleted.

Answer 1

As there is at beginning :

using PInvoke;

Then you use the package PInvoke.User32

then if you add at beginning

using static PInvoke.User32;

it will add needed definitions as VS suggests

(I tested by just copy/pasting your code)

Answer 2

For example, from internal class Win32 for P/Invoke -

    internal const int WM_GETMINMAXINFO = 0X0024;

    [StructLayout(LayoutKind.Sequential)]
    internal struct POINT
    {
        public int x;
        public int y;
    }

    [StructLayout(LayoutKind.Sequential)]
    internal struct MINMAXINFO
    {
        public POINT ptReserved;
        public POINT ptMaxSize;
        public POINT ptMaxPosition;
        public POINT ptMinTrackSize;
        public POINT ptMaxTrackSize;
    }
//
    Win32.MINMAXINFO mminfo = (Win32.MINMAXINFO )Marshal.PtrToStructure(m.LParam, typeof(Win32.MINMAXINFO));