C# monitor keyboard and print pressed key

using system; 
using system.windows.forms;
using system.runtime.interopservices;
using system.diagnostics;

namespace consoleapplication3
{
    class monitorhelper
    {
        internal const int whkeyboardllvalue = 13;
        internal const int wmkeydownvalue = 0x0100;
        internal static lowlevelkeyboardproc procvalue = hookcallback;
        internal static intptr hookidvalue = intptr.zero;
        internal delegate intptr lowlevelkeyboardproc(int ncode, intptr wparam, intptr lparam);

        [dllimport("user32.dll", charset = charset.auto, setlasterror = true)]
        internal static extern intptr setwindowshookex(int idhook, lowlevelkeyboardproc lpfn, intptr hmod, uint dwthreadid);

        [dllimport("user32.dll", charset = charset.auto, setlasterror = true)]
        [return: marshalas(unmanagedtype.bool)]
        internal static extern bool unhookwindowshookex(intptr hhk);

        [dllimport("user32.dll", charset = charset.auto, setlasterror = true)]
        internal static extern intptr callnexthookex(intptr hhk, int ncode, intptr wparam, intptr lparam);

        [dllimport("kernel32.dll", charset = charset.auto, setlasterror = true)]
        internal static extern intptr getmodulehandle(string lpmodulename);

        internal static intptr hookcallback(int ncode, intptr wparam, intptr lparam)
        {
            if (ncode >= 0 && wparam == (intptr)wmkeydownvalue)
            {
                int vkcode = marshal.readint32(lparam);
                console.writeline((keys)vkcode);
            }

            return callnexthookex(hookidvalue, ncode, wparam, lparam);
        }

        internal static intptr sethook(lowlevelkeyboardproc proc)
        {
            using (process curprocess = process.getcurrentprocess())
            using (processmodule curmodule = curprocess.mainmodule)
            {
                return setwindowshookex(whkeyboardllvalue, proc,
                    getmodulehandle(curmodule.modulename), 0);
            }
        }
    }
}

using system.windows.forms;
 static void main(string[] args)
        {
            monitordemo();
            console.readline();
        }

        static void monitordemo()
        {
            monitorhelper.hookidvalue = monitorhelper.sethook(monitorhelper.procvalue);
            application.run();
            monitorhelper.unhookwindowshookex(monitorhelper.hookidvalue);
        }

 

referenced  

 

#region assembly system.windows.forms, version=4.0.0.0, culture=neutral, publickeytoken=b77a5c561934e089
// c:\program files (x86)\reference assemblies\microsoft\framework\.netframework\v4.7.2\system.windows.forms.dll
#endregion

using system.componentmodel;
using system.runtime.interopservices;

namespace system.windows.forms
{
    //
    // summary:
    //     specifies key codes and modifiers.
    [comvisible(true)]
    [editor("system.windows.forms.design.shortcutkeyseditor, system.design, version=4.0.0.0, culture=neutral, publickeytoken=b03f5f7f11d50a3a", typeof(drawing.design.uitypeeditor))]
    [flags]
    [typeconverter(typeof(keysconverter))]
    public enum keys
    {
        //
        // summary:
        //     the bitmask to extract modifiers from a key value.
        modifiers = -65536,
        //
        // summary:
        //     no key pressed.
        none = 0,
        //
        // summary:
        //     the left mouse button.
        lbutton = 1,
        //
        // summary:
        //     the right mouse button.
        rbutton = 2,
        //
        // summary:
        //     the cancel key.
        cancel = 3,
        //
        // summary:
        //     the middle mouse button (three-button mouse).
        mbutton = 4,
        //
        // summary:
        //     the first x mouse button (five-button mouse).
        xbutton1 = 5,
        //
        // summary:
        //     the second x mouse button (five-button mouse).
        xbutton2 = 6,
        //
        // summary:
        //     the backspace key.
        back = 8,
        //
        // summary:
        //     the tab key.
        tab = 9,
        //
        // summary:
        //     the linefeed key.
        linefeed = 10,
        //
        // summary:
        //     the clear key.
        clear = 12,
        //
        // summary:
        //     the return key.
        return = 13,
        //
        // summary:
        //     the enter key.
        enter = 13,
        //
        // summary:
        //     the shift key.
        shiftkey = 16,
        //
        // summary:
        //     the ctrl key.
        controlkey = 17,
        //
        // summary:
        //     the alt key.
        menu = 18,
        //
        // summary:
        //     the pause key.
        pause = 19,
        //
        // summary:
        //     the caps lock key.
        capital = 20,
        //
        // summary:
        //     the caps lock key.
        capslock = 20,
        //
        // summary:
        //     the ime kana mode key.
        kanamode = 21,
        //
        // summary:
        //     the ime hanguel mode key. (maintained for compatibility; use hangulmode)
        hanguelmode = 21,
        //
        // summary:
        //     the ime hangul mode key.
        hangulmode = 21,
        //
        // summary:
        //     the ime junja mode key.
        junjamode = 23,
        //
        // summary:
        //     the ime final mode key.
        finalmode = 24,
        //
        // summary:
        //     the ime hanja mode key.
        hanjamode = 25,
        //
        // summary:
        //     the ime kanji mode key.
        kanjimode = 25,
        //
        // summary:
        //     the esc key.
        escape = 27,
        //
        // summary:
        //     the ime convert key.
        imeconvert = 28,
        //
        // summary:
        //     the ime nonconvert key.
        imenonconvert = 29,
        //
        // summary:
        //     the ime accept key, replaces system.windows.forms.keys.imeaceept.
        imeaccept = 30,
        //
        // summary:
        //     the ime accept key. obsolete, use system.windows.forms.keys.imeaccept instead.
        imeaceept = 30,
        //
        // summary:
        //     the ime mode change key.
        imemodechange = 31,
        //
        // summary:
        //     the spacebar key.
        space = 32,
        //
        // summary:
        //     the page up key.
        prior = 33,
        //
        // summary:
        //     the page up key.
        pageup = 33,
        //
        // summary:
        //     the page down key.
        next = 34,
        //
        // summary:
        //     the page down key.
        pagedown = 34,
        //
        // summary:
        //     the end key.
        end = 35,
        //
        // summary:
        //     the home key.
        home = 36,
        //
        // summary:
        //     the left arrow key.
        left = 37,
        //
        // summary:
        //     the up arrow key.
        up = 38,
        //
        // summary:
        //     the right arrow key.
        right = 39,
        //
        // summary:
        //     the down arrow key.
        down = 40,
        //
        // summary:
        //     the select key.
        select = 41,
        //
        // summary:
        //     the print key.
        print = 42,
        //
        // summary:
        //     the execute key.
        execute = 43,
        //
        // summary:
        //     the print screen key.
        snapshot = 44,
        //
        // summary:
        //     the print screen key.
        printscreen = 44,
        //
        // summary:
        //     the ins key.
        insert = 45,
        //
        // summary:
        //     the del key.
        delete = 46,
        //
        // summary:
        //     the help key.
        help = 47,
        //
        // summary:
        //     the 0 key.
        d0 = 48,
        //
        // summary:
        //     the 1 key.
        d1 = 49,
        //
        // summary:
        //     the 2 key.
        d2 = 50,
        //
        // summary:
        //     the 3 key.
        d3 = 51,
        //
        // summary:
        //     the 4 key.
        d4 = 52,
        //
        // summary:
        //     the 5 key.
        d5 = 53,
        //
        // summary:
        //     the 6 key.
        d6 = 54,
        //
        // summary:
        //     the 7 key.
        d7 = 55,
        //
        // summary:
        //     the 8 key.
        d8 = 56,
        //
        // summary:
        //     the 9 key.
        d9 = 57,
        //
        // summary:
        //     the a key.
        a = 65,
        //
        // summary:
        //     the b key.
        b = 66,
        //
        // summary:
        //     the c key.
        c = 67,
        //
        // summary:
        //     the d key.
        d = 68,
        //
        // summary:
        //     the e key.
        e = 69,
        //
        // summary:
        //     the f key.
        f = 70,
        //
        // summary:
        //     the g key.
        g = 71,
        //
        // summary:
        //     the h key.
        h = 72,
        //
        // summary:
        //     the i key.
        i = 73,
        //
        // summary:
        //     the j key.
        j = 74,
        //
        // summary:
        //     the k key.
        k = 75,
        //
        // summary:
        //     the l key.
        l = 76,
        //
        // summary:
        //     the m key.
        m = 77,
        //
        // summary:
        //     the n key.
        n = 78,
        //
        // summary:
        //     the o key.
        o = 79,
        //
        // summary:
        //     the p key.
        p = 80,
        //
        // summary:
        //     the q key.
        q = 81,
        //
        // summary:
        //     the r key.
        r = 82,
        //
        // summary:
        //     the s key.
        s = 83,
        //
        // summary:
        //     the t key.
        t = 84,
        //
        // summary:
        //     the u key.
        u = 85,
        //
        // summary:
        //     the v key.
        v = 86,
        //
        // summary:
        //     the w key.
        w = 87,
        //
        // summary:
        //     the x key.
        x = 88,
        //
        // summary:
        //     the y key.
        y = 89,
        //
        // summary:
        //     the z key.
        z = 90,
        //
        // summary:
        //     the left windows logo key (microsoft natural keyboard).
        lwin = 91,
        //
        // summary:
        //     the right windows logo key (microsoft natural keyboard).
        rwin = 92,
        //
        // summary:
        //     the application key (microsoft natural keyboard).
        apps = 93,
        //
        // summary:
        //     the computer sleep key.
        sleep = 95,
        //
        // summary:
        //     the 0 key on the numeric keypad.
        numpad0 = 96,
        //
        // summary:
        //     the 1 key on the numeric keypad.
        numpad1 = 97,
        //
        // summary:
        //     the 2 key on the numeric keypad.
        numpad2 = 98,
        //
        // summary:
        //     the 3 key on the numeric keypad.
        numpad3 = 99,
        //
        // summary:
        //     the 4 key on the numeric keypad.
        numpad4 = 100,
        //
        // summary:
        //     the 5 key on the numeric keypad.
        numpad5 = 101,
        //
        // summary:
        //     the 6 key on the numeric keypad.
        numpad6 = 102,
        //
        // summary:
        //     the 7 key on the numeric keypad.
        numpad7 = 103,
        //
        // summary:
        //     the 8 key on the numeric keypad.
        numpad8 = 104,
        //
        // summary:
        //     the 9 key on the numeric keypad.
        numpad9 = 105,
        //
        // summary:
        //     the multiply key.
        multiply = 106,
        //
        // summary:
        //     the add key.
        add = 107,
        //
        // summary:
        //     the separator key.
        separator = 108,
        //
        // summary:
        //     the subtract key.
        subtract = 109,
        //
        // summary:
        //     the decimal key.
        decimal = 110,
        //
        // summary:
        //     the divide key.
        divide = 111,
        //
        // summary:
        //     the f1 key.
        f1 = 112,
        //
        // summary:
        //     the f2 key.
        f2 = 113,
        //
        // summary:
        //     the f3 key.
        f3 = 114,
        //
        // summary:
        //     the f4 key.
        f4 = 115,
        //
        // summary:
        //     the f5 key.
        f5 = 116,
        //
        // summary:
        //     the f6 key.
        f6 = 117,
        //
        // summary:
        //     the f7 key.
        f7 = 118,
        //
        // summary:
        //     the f8 key.
        f8 = 119,
        //
        // summary:
        //     the f9 key.
        f9 = 120,
        //
        // summary:
        //     the f10 key.
        f10 = 121,
        //
        // summary:
        //     the f11 key.
        f11 = 122,
        //
        // summary:
        //     the f12 key.
        f12 = 123,
        //
        // summary:
        //     the f13 key.
        f13 = 124,
        //
        // summary:
        //     the f14 key.
        f14 = 125,
        //
        // summary:
        //     the f15 key.
        f15 = 126,
        //
        // summary:
        //     the f16 key.
        f16 = 127,
        //
        // summary:
        //     the f17 key.
        f17 = 128,
        //
        // summary:
        //     the f18 key.
        f18 = 129,
        //
        // summary:
        //     the f19 key.
        f19 = 130,
        //
        // summary:
        //     the f20 key.
        f20 = 131,
        //
        // summary:
        //     the f21 key.
        f21 = 132,
        //
        // summary:
        //     the f22 key.
        f22 = 133,
        //
        // summary:
        //     the f23 key.
        f23 = 134,
        //
        // summary:
        //     the f24 key.
        f24 = 135,
        //
        // summary:
        //     the num lock key.
        numlock = 144,
        //
        // summary:
        //     the scroll lock key.
        scroll = 145,
        //
        // summary:
        //     the left shift key.
        lshiftkey = 160,
        //
        // summary:
        //     the right shift key.
        rshiftkey = 161,
        //
        // summary:
        //     the left ctrl key.
        lcontrolkey = 162,
        //
        // summary:
        //     the right ctrl key.
        rcontrolkey = 163,
        //
        // summary:
        //     the left alt key.
        lmenu = 164,
        //
        // summary:
        //     the right alt key.
        rmenu = 165,
        //
        // summary:
        //     the browser back key (windows 2000 or later).
        browserback = 166,
        //
        // summary:
        //     the browser forward key (windows 2000 or later).
        browserforward = 167,
        //
        // summary:
        //     the browser refresh key (windows 2000 or later).
        browserrefresh = 168,
        //
        // summary:
        //     the browser stop key (windows 2000 or later).
        browserstop = 169,
        //
        // summary:
        //     the browser search key (windows 2000 or later).
        browsersearch = 170,
        //
        // summary:
        //     the browser favorites key (windows 2000 or later).
        browserfavorites = 171,
        //
        // summary:
        //     the browser home key (windows 2000 or later).
        browserhome = 172,
        //
        // summary:
        //     the volume mute key (windows 2000 or later).
        volumemute = 173,
        //
        // summary:
        //     the volume down key (windows 2000 or later).
        volumedown = 174,
        //
        // summary:
        //     the volume up key (windows 2000 or later).
        volumeup = 175,
        //
        // summary:
        //     the media next track key (windows 2000 or later).
        medianexttrack = 176,
        //
        // summary:
        //     the media previous track key (windows 2000 or later).
        mediaprevioustrack = 177,
        //
        // summary:
        //     the media stop key (windows 2000 or later).
        mediastop = 178,
        //
        // summary:
        //     the media play pause key (windows 2000 or later).
        mediaplaypause = 179,
        //
        // summary:
        //     the launch mail key (windows 2000 or later).
        launchmail = 180,
        //
        // summary:
        //     the select media key (windows 2000 or later).
        selectmedia = 181,
        //
        // summary:
        //     the start application one key (windows 2000 or later).
        launchapplication1 = 182,
        //
        // summary:
        //     the start application two key (windows 2000 or later).
        launchapplication2 = 183,
        //
        // summary:
        //     the oem semicolon key on a us standard keyboard (windows 2000 or later).
        oemsemicolon = 186,
        //
        // summary:
        //     the oem 1 key.
        oem1 = 186,
        //
        // summary:
        //     the oem plus key on any country/region keyboard (windows 2000 or later).
        oemplus = 187,
        //
        // summary:
        //     the oem comma key on any country/region keyboard (windows 2000 or later).
        oemcomma = 188,
        //
        // summary:
        //     the oem minus key on any country/region keyboard (windows 2000 or later).
        oemminus = 189,
        //
        // summary:
        //     the oem period key on any country/region keyboard (windows 2000 or later).
        oemperiod = 190,
        //
        // summary:
        //     the oem question mark key on a us standard keyboard (windows 2000 or later).
        oemquestion = 191,
        //
        // summary:
        //     the oem 2 key.
        oem2 = 191,
        //
        // summary:
        //     the oem tilde key on a us standard keyboard (windows 2000 or later).
        oemtilde = 192,
        //
        // summary:
        //     the oem 3 key.
        oem3 = 192,
        //
        // summary:
        //     the oem open bracket key on a us standard keyboard (windows 2000 or later).
        oemopenbrackets = 219,
        //
        // summary:
        //     the oem 4 key.
        oem4 = 219,
        //
        // summary:
        //     the oem pipe key on a us standard keyboard (windows 2000 or later).
        oempipe = 220,
        //
        // summary:
        //     the oem 5 key.
        oem5 = 220,
        //
        // summary:
        //     the oem close bracket key on a us standard keyboard (windows 2000 or later).
        oemclosebrackets = 221,
        //
        // summary:
        //     the oem 6 key.
        oem6 = 221,
        //
        // summary:
        //     the oem singled/double quote key on a us standard keyboard (windows 2000 or later).
        oemquotes = 222,
        //
        // summary:
        //     the oem 7 key.
        oem7 = 222,
        //
        // summary:
        //     the oem 8 key.
        oem8 = 223,
        //
        // summary:
        //     the oem angle bracket or backslash key on the rt 102 key keyboard (windows 2000
        //     or later).
        oembackslash = 226,
        //
        // summary:
        //     the oem 102 key.
        oem102 = 226,
        //
        // summary:
        //     the process key key.
        processkey = 229,
        //
        // summary:
        //     used to pass unicode characters as if they were keystrokes. the packet key value
        //     is the low word of a 32-bit virtual-key value used for non-keyboard input methods.
        packet = 231,
        //
        // summary:
        //     the attn key.
        attn = 246,
        //
        // summary:
        //     the crsel key.
        crsel = 247,
        //
        // summary:
        //     the exsel key.
        exsel = 248,
        //
        // summary:
        //     the erase eof key.
        eraseeof = 249,
        //
        // summary:
        //     the play key.
        play = 250,
        //
        // summary:
        //     the zoom key.
        zoom = 251,
        //
        // summary:
        //     a constant reserved for future use.
        noname = 252,
        //
        // summary:
        //     the pa1 key.
        pa1 = 253,
        //
        // summary:
        //     the clear key.
        oemclear = 254,
        //
        // summary:
        //     the bitmask to extract a key code from a key value.
        keycode = 65535,
        //
        // summary:
        //     the shift modifier key.
        shift = 65536,
        //
        // summary:
        //     the ctrl modifier key.
        control = 131072,
        //
        // summary:
        //     the alt modifier key.
        alt = 262144
    }
}