在ubuntu上使用GetAsyncKeyState时出现C#错误

using System;
using System.Runtime.InteropServices;

public class Program
{
    [DllImport("libX11")]
    private static extern IntPtr XOpenDisplay(IntPtr display);

    [DllImport("libX11")]
    private static extern int XCloseDisplay(IntPtr display);

    [DllImport("libX11")]
    private static extern int XNextEvent(IntPtr display, ref XEvent xevent);

    [StructLayout(LayoutKind.Sequential)]
    private struct XEvent
    {
        public int type;
        public IntPtr xkey;
    }

    private const int KeyPress = 2;
    private const int KeyRelease = 3;

    public static void Main()
    {
        IntPtr display = XOpenDisplay(IntPtr.Zero);
        if (display == IntPtr.Zero)
        {
            Console.WriteLine("无法打开显示");
            return;
        }

        XEvent xevent = new XEvent();
        while (true)
        {
            XNextEvent(display, ref xevent);
            if (xevent.type == KeyPress)
            {
                Console.WriteLine("按下键盘");
            }
            else if (xevent.type == KeyRelease)
            {
                Console.WriteLine("释放键盘");
            }
        }

        XCloseDisplay(display);
    }
}