Отключить ключевые события на определенном устройстве (глобальный keyhook) - PullRequest
0 голосов
/ 04 февраля 2019

Я пытаюсь отключить вход от сканера штрих-кода, когда он мне не нужен.У меня есть активная клавиатура и сканер штрих-кода (мы можем назвать это другой клавиатурой).Мне удалось получить ключи для событий KEYDOWN и KEYUP и установить e.Handled = true, чтобы отключить определенные ключи.Теперь мне нужна помощь, как отключить все ключи от определенного устройства.

Я искал код из этих двух статей: https://stackoverflow.com/a/34384189/4183512 https://www.codeproject.com/Articles/17123/Using-Raw-Input-from-C-to-handle-multiple-keyboard

Мне удалось получитьс какого устройства ключ поступает во 2-й статье и отключает определенные ключи в 1-й, но не знаю, как реализовать распознавание устройства из второй статьи в первую.

Вот что у меня есть:

HOOK CLASS FROM 1-ой ССЫЛКИ

namespace DisableBarcode
{
    class GlobalKeyboardHookEventArgs : HandledEventArgs
    {
        public GlobalKeyboardHook.KeyboardState KeyboardState { get; private set; }
        public GlobalKeyboardHook.LowLevelKeyboardInputEvent KeyboardData { get; private set; }

        public GlobalKeyboardHookEventArgs(
            GlobalKeyboardHook.LowLevelKeyboardInputEvent keyboardData,
            GlobalKeyboardHook.KeyboardState keyboardState)
        {
            KeyboardData = keyboardData;
            KeyboardState = keyboardState;
        }
    }

    //Based on https://gist.github.com/Stasonix
    class GlobalKeyboardHook : IDisposable
    {
        public event EventHandler<GlobalKeyboardHookEventArgs> KeyboardPressed;

        public GlobalKeyboardHook()
        {
            _windowsHookHandle = IntPtr.Zero;
            _user32LibraryHandle = IntPtr.Zero;
            _hookProc = LowLevelKeyboardProc; // we must keep alive _hookProc, because GC is not aware about SetWindowsHookEx behaviour.

            _user32LibraryHandle = LoadLibrary("User32");
            if (_user32LibraryHandle == IntPtr.Zero)
            {
                int errorCode = Marshal.GetLastWin32Error();
                throw new Win32Exception(errorCode, "Failed to load library 'User32.dll'. Error {errorCode}: {new Win32Exception(Marshal.GetLastWin32Error()).Message}.");
            }



            _windowsHookHandle = SetWindowsHookEx(WH_KEYBOARD_LL, _hookProc, _user32LibraryHandle, 0);
            if (_windowsHookHandle == IntPtr.Zero)
            {
                int errorCode = Marshal.GetLastWin32Error();
                throw new Win32Exception(errorCode, "Failed to adjust keyboard hooks for '{Process.GetCurrentProcess().ProcessName}'. Error {errorCode}: {new Win32Exception(Marshal.GetLastWin32Error()).Message}.");
            }
        }

        protected virtual void Dispose(bool disposing)
        {
            if (disposing)
            {
                // because we can unhook only in the same thread, not in garbage collector thread
                if (_windowsHookHandle != IntPtr.Zero)
                {
                    if (!UnhookWindowsHookEx(_windowsHookHandle))
                    {
                        int errorCode = Marshal.GetLastWin32Error();
                        throw new Win32Exception(errorCode, "Failed to remove keyboard hooks for '{Process.GetCurrentProcess().ProcessName}'. Error {errorCode}: {new Win32Exception(Marshal.GetLastWin32Error()).Message}.");
                    }
                    _windowsHookHandle = IntPtr.Zero;

                    // ReSharper disable once DelegateSubtraction
                    _hookProc -= LowLevelKeyboardProc;
                }
            }

            if (_user32LibraryHandle != IntPtr.Zero)
            {
                if (!FreeLibrary(_user32LibraryHandle)) // reduces reference to library by 1.
                {
                    int errorCode = Marshal.GetLastWin32Error();
                    throw new Win32Exception(errorCode, "Failed to unload library 'User32.dll'. Error {errorCode}: {new Win32Exception(Marshal.GetLastWin32Error()).Message}.");
                }
                _user32LibraryHandle = IntPtr.Zero;
            }
        }

        ~GlobalKeyboardHook()
        {
            Dispose(false);
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        private IntPtr _windowsHookHandle;
        private IntPtr _user32LibraryHandle;
        private HookProc _hookProc;

        delegate IntPtr HookProc(int nCode, IntPtr wParam, IntPtr lParam);

        [DllImport("kernel32.dll")]
        private static extern IntPtr LoadLibrary(string lpFileName);

        [DllImport("kernel32.dll", CharSet = CharSet.Auto)]
        private static extern bool FreeLibrary(IntPtr hModule);

        /// <summary>
        /// The SetWindowsHookEx function installs an application-defined hook procedure into a hook chain.
        /// You would install a hook procedure to monitor the system for certain types of events. These events are
        /// associated either with a specific thread or with all threads in the same desktop as the calling thread.
        /// </summary>
        /// <param name="idHook">hook type</param>
        /// <param name="lpfn">hook procedure</param>
        /// <param name="hMod">handle to application instance</param>
        /// <param name="dwThreadId">thread identifier</param>
        /// <returns>If the function succeeds, the return value is the handle to the hook procedure.</returns>
        [DllImport("USER32", SetLastError = true)]
        static extern IntPtr SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hMod, int dwThreadId);

        /// <summary>
        /// The UnhookWindowsHookEx function removes a hook procedure installed in a hook chain by the SetWindowsHookEx function.
        /// </summary>
        /// <param name="hhk">handle to hook procedure</param>
        /// <returns>If the function succeeds, the return value is true.</returns>
        [DllImport("USER32", SetLastError = true)]
        public static extern bool UnhookWindowsHookEx(IntPtr hHook);

        /// <summary>
        /// The CallNextHookEx function passes the hook information to the next hook procedure in the current hook chain.
        /// A hook procedure can call this function either before or after processing the hook information.
        /// </summary>
        /// <param name="hHook">handle to current hook</param>
        /// <param name="code">hook code passed to hook procedure</param>
        /// <param name="wParam">value passed to hook procedure</param>
        /// <param name="lParam">value passed to hook procedure</param>
        /// <returns>If the function succeeds, the return value is true.</returns>
        [DllImport("USER32", SetLastError = true)]
        static extern IntPtr CallNextHookEx(IntPtr hHook, int code, IntPtr wParam, IntPtr lParam);

        [StructLayout(LayoutKind.Sequential)]
        public struct LowLevelKeyboardInputEvent
        {
            /// <summary>
            /// A virtual-key code. The code must be a value in the range 1 to 254.
            /// </summary>
            public int VirtualCode;

            /// <summary>
            /// A hardware scan code for the key. 
            /// </summary>
            public int HardwareScanCode;

            /// <summary>
            /// The extended-key flag, event-injected Flags, context code, and transition-state flag. This member is specified as follows. An application can use the following values to test the keystroke Flags. Testing LLKHF_INJECTED (bit 4) will tell you whether the event was injected. If it was, then testing LLKHF_LOWER_IL_INJECTED (bit 1) will tell you whether or not the event was injected from a process running at lower integrity level.
            /// </summary>
            public int Flags;

            /// <summary>
            /// The time stamp stamp for this message, equivalent to what GetMessageTime would return for this message.
            /// </summary>
            public int TimeStamp;

            /// <summary>
            /// Additional information associated with the message. 
            /// </summary>
            public IntPtr AdditionalInformation;
        }

        public const int WH_KEYBOARD_LL = 13;
        //const int HC_ACTION = 0;

        public enum KeyboardState
        {
            KeyDown = 0x0100,
            KeyUp = 0x0101,
            SysKeyDown = 0x0104,
            SysKeyUp = 0x0105
        }

        public const int VkSnapshot = 0x2c;
        //const int VkLwin = 0x5b;
        //const int VkRwin = 0x5c;
        //const int VkTab = 0x09;
        //const int VkEscape = 0x18;
        //const int VkControl = 0x11;
        const int KfAltdown = 0x2000;
        public const int LlkhfAltdown = (KfAltdown >> 8);

        public IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam)
        {
            bool fEatKeyStroke = false;

            var wparamTyped = wParam.ToInt32();
            if (Enum.IsDefined(typeof(KeyboardState), wparamTyped))
            {
                object o = Marshal.PtrToStructure(lParam, typeof(LowLevelKeyboardInputEvent));
                LowLevelKeyboardInputEvent p = (LowLevelKeyboardInputEvent)o;

                var eventArguments = new GlobalKeyboardHookEventArgs(p, (KeyboardState)wparamTyped);

                EventHandler<GlobalKeyboardHookEventArgs> handler = KeyboardPressed;
                handler.Invoke(this, eventArguments);

                fEatKeyStroke = eventArguments.Handled;
            }

            return fEatKeyStroke ? (IntPtr)1 : CallNextHookEx(IntPtr.Zero, nCode, wParam, lParam);
        }
    }
}

CODEBEHIND

 public partial class App : Application
    {

        private void Application_Startup(object sender, StartupEventArgs e)
        {
            MainWindow wnd = new MainWindow();
            wnd.Show();
            SetupKeyboardHooks();
        }


        #region KeyHooks
        private GlobalKeyboardHook _globalKeyboardHook;

        public void SetupKeyboardHooks()
        {
            _globalKeyboardHook = new GlobalKeyboardHook();
            _globalKeyboardHook.KeyboardPressed += OnKeyPressed;
        }

        private void OnKeyPressed(object sender, GlobalKeyboardHookEventArgs e)
        {


            //TODO: if device is barcode scanner do {x}... else do {y} ....


            if (e.KeyboardData.VirtualCode == 65)  //ignore the "a" key
                e.Handled = true;

        }

        public void Dispose()
        {
            _globalKeyboardHook.Dispose();
        }

        #endregion


    }

Мне, вероятно, нужно добавить материал в "struct LowLevelKeyboardInputEvent", чтобы тоже получить информацию об устройстве, но понятия не имею, как.

Заранее спасибо за помощь!

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