mono csharp linux(ubuntu) global hook keyboard

Question

me need realized global hook in mono csharp, i read xkeyhook xkeyhookkeybord... no work all samples( hover me to think how best to implement .... thank*

    public X11Hotkey(Gdk.Key key, Gdk.ModifierType modifiers)
    {
        this.key = key;
        this.modifiers = modifiers;

        Gdk.Window rootWin = Gdk.Global.DefaultRootWindow;
        IntPtr xDisplay = GetXDisplay(rootWin);
        this.keycode = XKeysymToKeycode(xDisplay, (int)this.key);
        //here ask the filter 
        rootWin.AddFilter(new Gdk.FilterFunc(FilterFunction));
    }

    //function is not executed
    private Gdk.FilterReturn FilterFunction(IntPtr xEvent, Gdk.Event evnt)
    {
        XKeyEvent xKeyEvent = (XKeyEvent)Marshal.PtrToStructure(
            xEvent, 
            typeof(XKeyEvent));

        if (xKeyEvent.type == KeyPress)
        {
            if (xKeyEvent.keycode == this.keycode 
                && xKeyEvent.state == (uint)this.modifiers)
            {
                this.OnPressed(EventArgs.Empty);
            }
        }

        return Gdk.FilterReturn.Continue;
    }

filter no return evenе... what to do??

Answer 1

 public delegate void SpecialKeyPressedHandler(object o, SpecialKey key);

    public enum SpecialKey 
    {
        one = Gdk.Key.exclam,
        two = Gdk.Key.at,
        tree = Gdk.Key.numbersign,
        four = Gdk.Key.dollar,
        five = Gdk.Key.percent,
        six = Gdk.Key.asciicircum,
        seven = Gdk.Key.ampersand,
        eight = Gdk.Key.asterisk,
        nine = Gdk.Key.parenleft,
        nul = Gdk.Key.parenright,
        retu = Gdk.Key.Return

    };

    public class SpecialKeys
    {
        private Hashtable key_map = new Hashtable();
        private Hashtable key_registrations = new Hashtable();
        private IEnumerable keycode_list;
        private TimeSpan raise_delay = new TimeSpan(0);
        private DateTime last_raise = DateTime.MinValue;

        public SpecialKeys()
        {
            Console.WriteLine("init");
            keycode_list = BuildKeyCodeList();
            InitializeKeys();
        }

        public void Dispose()
        {
            UnitializeKeys();
        }

        public void RegisterHandler(SpecialKeyPressedHandler handler, params SpecialKey [] specialKeys)
        {
            foreach(SpecialKey specialKey in specialKeys) {
                if(key_map.Contains(specialKey)) {
                    int key = (int)key_map[specialKey];
                    key_registrations[key] = Delegate.Combine(key_registrations[key] as Delegate, handler);
                }
            }
        }

        public void UnregisterHandler(SpecialKeyPressedHandler handler, params SpecialKey [] specialKeys)
        {
            foreach(SpecialKey specialKey in specialKeys) {
                if(key_map.Contains(specialKey)) {
                    int key = (int)key_map[specialKey];
                    key_registrations[key] = Delegate.Remove(key_registrations[key] as Delegate, handler); 
                }
            }
        }

        private IEnumerable BuildKeyCodeList()
        {
            ArrayList kc_list = new ArrayList();

            foreach(SpecialKey key in Enum.GetValues(typeof(SpecialKey))) {
                IntPtr xdisplay = gdk_x11_get_default_xdisplay();

                if(!xdisplay.Equals(IntPtr.Zero)) {
                    int keycode = XKeysymToKeycode(xdisplay, key);
                    if(keycode != 0) {
                        key_map[keycode] = key;
                        key_map[key] = keycode;
                        kc_list.Add(keycode);
                    }
                }
            }
            return kc_list;
        }

        private void InitializeKeys()
        {
            for(int i = 0; i < Gdk.Display.Default.NScreens; i++) {
                Gdk.Screen screen = Gdk.Display.Default.GetScreen(i);

                foreach(int keycode in keycode_list) {
                    GrabKey(screen.RootWindow, keycode);
                }
                screen.RootWindow.AddFilter(FilterKey);
            }


        }

        private void UnitializeKeys() 
        {
            for(int i = 0; i < Gdk.Display.Default.NScreens; i++) {
                Gdk.Screen screen = Gdk.Display.Default.GetScreen(i);
                foreach(int keycode in keycode_list) {
                    UngrabKey(screen.RootWindow, keycode);
                }
                screen.RootWindow.RemoveFilter(FilterKey);
            }
        }

        private void GrabKey(Gdk.Window root, int keycode)
        {   

            IntPtr xid = gdk_x11_drawable_get_xid(root.Handle);
            IntPtr xdisplay = gdk_x11_get_default_xdisplay();

            gdk_error_trap_push();

            XGrabKey(xdisplay, keycode, XModMask.None, xid, true, XGrabMode.Async, XGrabMode.Async);
            XGrabKey(xdisplay, keycode, XModMask.Mod2, xid, true, XGrabMode.Async, XGrabMode.Async);
            XGrabKey(xdisplay, keycode, XModMask.Mod5, xid, true, XGrabMode.Async, XGrabMode.Async);
            XGrabKey(xdisplay, keycode, XModMask.Lock, xid, true, XGrabMode.Async, XGrabMode.Async);
            XGrabKey(xdisplay, keycode, XModMask.Mod2 | XModMask.Mod5, xid, true, XGrabMode.Async, XGrabMode.Async);
            XGrabKey(xdisplay, keycode, XModMask.Mod2 | XModMask.Lock, xid, true, XGrabMode.Async, XGrabMode.Async);
            XGrabKey(xdisplay, keycode, XModMask.Mod5 | XModMask.Lock, xid, true, XGrabMode.Async, XGrabMode.Async);
            XGrabKey(xdisplay, keycode, XModMask.Mod2 | XModMask.Mod5 | XModMask.Lock, xid, true, 
                XGrabMode.Async, XGrabMode.Async);

            gdk_flush();

            if(gdk_error_trap_pop() != 0) {
                Console.Error.WriteLine(": Could not grab key {0} (maybe another application has grabbed this key)", keycode);
            }
        }

        private void UngrabKey(Gdk.Window root, int keycode)
        {
            IntPtr xid = gdk_x11_drawable_get_xid(root.Handle);
            IntPtr xdisplay = gdk_x11_get_default_xdisplay();

            gdk_error_trap_push();

            XUngrabKey(xdisplay, keycode, XModMask.None, xid);
            XUngrabKey(xdisplay, keycode, XModMask.Mod2, xid);
            XUngrabKey(xdisplay, keycode, XModMask.Mod5, xid);
            XUngrabKey(xdisplay, keycode, XModMask.Lock, xid);
            XUngrabKey(xdisplay, keycode, XModMask.Mod2 | XModMask.Mod5, xid);
            XUngrabKey(xdisplay, keycode, XModMask.Mod2 | XModMask.Lock, xid);
            XUngrabKey(xdisplay, keycode, XModMask.Mod5 | XModMask.Lock, xid);
            XUngrabKey(xdisplay, keycode, XModMask.Mod2 | XModMask.Mod5 | XModMask.Lock,xid);

            gdk_flush();

            if(gdk_error_trap_pop() != 0) {
                Console.Error.WriteLine(": Could not ungrab key {0} (maybe another application has grabbed this key)", keycode);
            }
        }

        private Gdk.FilterReturn FilterKey(IntPtr xeventPtr, Gdk.Event gdkEvent)
        {
            Console.WriteLine("filter "+ gdkEvent.Type);
            if(DateTime.Now - last_raise < raise_delay) {
                return Gdk.FilterReturn.Continue;
            }

            last_raise = DateTime.Now;

            XKeyEvent xevent = (XKeyEvent)Marshal.PtrToStructure(xeventPtr, typeof(XKeyEvent));

            if(xevent.type != XEventName.KeyPress) {
                return Gdk.FilterReturn.Continue;
            }

            int keycode = (int)xevent.keycode;
            object x = key_map[keycode];

            Console.WriteLine("filter "+ keycode);

            if(x == null) {
                return Gdk.FilterReturn.Continue;
            }

            SpecialKey key = (SpecialKey)key_map[keycode];

            if(key_registrations[keycode] != null) {
                x = key_registrations[keycode];
                if(x is SpecialKeyPressedHandler) {
                    ((SpecialKeyPressedHandler)x)(this, key);    
                }
                return Gdk.FilterReturn.Remove;
            }

            return Gdk.FilterReturn.Continue;
        }

        public TimeSpan Delay {
            get {
                return raise_delay;
            }

            set {
                raise_delay = value;
            }
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct XKeyEvent
        {
            public XEventName type;
            public IntPtr serial;
            public bool send_event;
            public IntPtr display;
            public IntPtr window;
            public IntPtr root;
            public IntPtr subwindow;
            public IntPtr time;
            public int x;
            public int y;
            public int x_root;
            public int x_y;
            public uint state;
            public uint keycode;
            public bool same_screen;
        }

        [DllImport("libX11")]
        private static extern int XKeysymToKeycode(IntPtr display, SpecialKey keysym);

        [DllImport("libX11")]
        private static extern void XGrabKey(IntPtr display, int keycode, XModMask modifiers, 
            IntPtr window, bool owner_events, XGrabMode pointer_mode, XGrabMode keyboard_mode);

        [DllImport("libX11")]
        private static extern void XUngrabKey(IntPtr display, int keycode, XModMask modifiers, 
            IntPtr window);

        [DllImport("gdk-x11-2.0")]
        private static extern IntPtr gdk_x11_drawable_get_xid(IntPtr window);

        [DllImport("gdk-x11-2.0")]
        private static extern IntPtr gdk_x11_get_default_xdisplay();

        [DllImport("gdk-x11-2.0")]
        private static extern void gdk_error_trap_push();

        [DllImport("gdk-x11-2.0")]
        private static extern int gdk_error_trap_pop();

        [DllImport("gdk-x11-2.0")]
        private static extern void gdk_flush();

        [Flags]
        private enum XModMask {
            None    = 0,
            Shift   = 1 << 0,
            Lock    = 1 << 1,
            Control = 1 << 2,
            Mod1    = 1 << 3,
            Mod2    = 1 << 4,
            Mod3    = 1 << 5,
            Mod4    = 1 << 6,
            Mod5    = 1 << 7
        }

        private enum XGrabMode {
            Sync  = 0,
            Async = 1
        }

        private enum XEventName {
            KeyPress   = 2,
            KeyRelease = 3,
        }
    }

all work!

Answer 2

GDK filters are not designed as global hooks. They will only give you events that would already be delivered to your process, before the normal processing.

To arrange to have keyboard events for a specific key combination delivered to your process, use the XGrabKey function with the root window. Note that some things not normally considered "modifiers", such as CapsLock, are considered modifiers by X11, and you will need to grab with all possible configurations of the modifiers you wish to ignore. You may also find this question useful.

X is not designed with global keyboard or mouse hooks in mind. While it is possible to have ALL events delivered to your process, it cannot be done without interfering with other processes.