when using KeyBoard hooks, how to filter control keys out

Question

I have a keyboard hook in order to receive data from the HID interface. It works, however, sometimes, a binary data is received causing windows to behave incorrectly.

This is the hook delegate:

    private IntPtr KeyboardHookDelegate(
        int nCode, IntPtr wParam, IntPtr lParam)
    {
        EventHandler<KeyboardEventArgs> handlerKeyPressed = KeyBoardKeyPressed;
        EventHandler<DataEventArgs> handlerData = KeyBoardDataPresent;
        if (handlerKeyPressed != null || handlerData != null)
        {
            _shiftPressed = KbdNativeMethods.GetAsyncKeyState(KbdNativeMethods.VirtualKeyStates.VK_SHIFT) < 0;
            _capsLockOn = KbdNativeMethods.GetAsyncKeyState(KbdNativeMethods.VirtualKeyStates.VK_CAPITAL) < 0;

            if (nCode == KbdNativeMethods.HC_ACTION)
            {
                KbdNativeMethods.KBDLLHOOKSTRUCT kbd = (KbdNativeMethods.KBDLLHOOKSTRUCT)Marshal.PtrToStructure(lParam, typeof(KbdNativeMethods.KBDLLHOOKSTRUCT));

                if ((wParam == (IntPtr)KbdNativeMethods.WM_SYSKEYDOWN) || (wParam == (IntPtr)KbdNativeMethods.WM_KEYDOWN))
                {
                    if (kbd.vkCode == (uint)KbdNativeMethods.VirtualKeyStates.VK_LSHIFT || kbd.vkCode == (uint)KbdNativeMethods.VirtualKeyStates.VK_RSHIFT)
                        _shiftPressed = true;
                    else if (kbd.vkCode == (uint)KbdNativeMethods.VirtualKeyStates.VK_CAPITAL)
                        _capsLockOn = true;
                    else
                    {
                        char charPressed = GetCharFromKey(kbd.vkCode, _shiftPressed ^ _capsLockOn, false);
                        var isPrintable = (int)charPressed <= 0x7F && (!char.IsControl(charPressed) || char.IsWhiteSpace(charPressed));
                        if (isPrintable)
                        {
                            //Console.Write(string.Format("0x{0:X2} , ", (int)charPressed));
                            //if (charPressed != '\r')
                            //    Console.Write(charPressed);

                            // Registra la última hora en que recibió un dato. Si ha pasado más de 3 segundos, debe limpiar el buffer.
                            DateTime newLastInput = GetLastInputTime();
                            if ((newLastInput - _lastInputTime).TotalSeconds >= 3)
                                _data.Clear();
                            _lastInputTime = newLastInput;

                            handlerKeyPressed?.Invoke(this, new KeyboardEventArgs() { Key = charPressed });

                            if (handlerData != null)
                            {
                                if (_data.Length > 500)
                                    _data.Clear();
                                _data.Append(charPressed);
                                string tmp = _data.ToString();
                                if (tmp.StartsWith(_prefijo) && tmp.EndsWith(_sufijo))
                                {
                                    _data.Clear();

                                    string pin = ExtractPinFromReading(tmp.Substring(_prefijo.Length, tmp.Length - _prefijo.Length - _sufijo.Length).Trim());
                                    if (pin != string.Empty)
                                        handlerData(this, new DataEventArgs() { SourceName = "KBD", Data = pin });
                                    else
                                        return IntPtr.Zero;
                                }
                            }
                        }
                        else if (charPressed != 0x1B)
                            return IntPtr.Zero;
                    }
                }
                else if ((wParam == (IntPtr)KbdNativeMethods.WM_SYSKEYUP) || (wParam == (IntPtr)KbdNativeMethods.WM_KEYUP))
                {
                    if (kbd.vkCode == (uint)KbdNativeMethods.VirtualKeyStates.VK_LSHIFT || kbd.vkCode == (uint)KbdNativeMethods.VirtualKeyStates.VK_RSHIFT)
                        _shiftPressed = false;
                    else if (kbd.vkCode == (uint)KbdNativeMethods.VirtualKeyStates.VK_CAPITAL)
                        _capsLockOn = false;
                }
                else
                    return IntPtr.Zero;
            }
        }

        return KbdNativeMethods.CallNextHookEx(_keyBoardHandle, nCode, wParam, lParam);
    }

As you can see, I am trying to filter those weird bytes out by returning IntPtr.Zero from the handler, but it did not work.

Any help please?