P/Invoke and Mono: EntryPointNotFoundException

Question

I'm trying to access the Wine implementation of some user32 functions on Kubuntu Linux. I have the Wine 1.1.31 package installed. When try running this simple test program in MonoDevelop, I get a System.EntryPointNotFoundException.

using System;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace PinvokeTesting
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            Console.WriteLine(GetKeyState((int)Keys.A));
        }

        [DllImport("user32")]
        private static extern short GetKeyState(int vKey);
    }
}

This is the output:

Unhandled Exception: System.EntryPointNotFoundException: GetKeyState at (wrapper managed-to-native) PinvokeTesting.MainClass:GetKeyState (int) at PinvokeTesting.MainClass.Main (System.String[] args) [0x00000] in .../Main.cs:11

The function should be there, but it's not finding it. Any ideas? I've done a lot of searching, haven't found anything helpful. The documentation seems to be rather sparse on these issues (either that or I'm searching for the wrong things).

Edit: I'm not trying to use P/Invoke in combination with Winforms, there are some other functions in Wine I need to P/Invoke to. I'm just trying to get Mono P/Invoke to Wine working.

Answer 1

The wine libs are completely incompatible with mono. If you need to use wine libs on Linux, you need to get the windows version of mono and run it under wine.

This has nothing to do with Winforms specifically, it holds true for any wine library.

As for the actual solution to your problem:

• Don't use the #ifdef WIN32API_NT_5 trick that has been suggested, instead use runtime detection and invoke one method or the other depending if you're running under windows or under different operating systems: having a single binary is worth the 1-cycle runtime penalty (moreoer if you store the operating system flag in a static readnly field mono will optimize the check away for you).
• You need to cope with different operating system models if you want your code to be portable, because it's not always possible to implement ant call from one system in another one in a simple or fully compatible way. For example in the GetKeyState() case you might need to hookup keyboard events and record the press/release state yourself.
• Consider different ways to do the same thing, for example, are your sure that the standard Console class in mscorlib doesn't provide the functuonality you need in your program?