Question

我有两段非常相似的代码，它们注册了全局钩子。

注册全局键盘钩子：

public class KeyboardHook : IDisposable
{
    #region Events
    private delegate IntPtr LowLevelKeyboardProc(int nCode, IntPtr wParam, IntPtr lParam);
    public delegate void HookEventHandler(object sender, KeyboardHookEventArgs e);
    public event HookEventHandler KeyDown;
    public event HookEventHandler KeyUp;
    #endregion

    #region Constants
    private const int WH_KEYBOARD_LL = 13;
    private const int WM_KEYDOWN = 0x0100;
    private const int WM_SYSKEYDOWN = 0x0104;
    private LowLevelKeyboardProc _proc = null;
    private static IntPtr _hookID = IntPtr.Zero;
    #endregion

    #region Imports
    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr SetWindowsHookEx(int idHook,
        LowLevelKeyboardProc lpfn, IntPtr hMod, uint dwThreadId);

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool UnhookWindowsHookEx(IntPtr hhk);

    [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode,
        IntPtr wParam, IntPtr lParam);

    [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
    private static extern IntPtr GetModuleHandle(string lpModuleName);

    #endregion

    #region Constructor
    public KeyboardHook()
    {
        _proc = new LowLevelKeyboardProc(HookCallback); 
        _hookID = SetHook(_proc);
    }

    #endregion


    #region Methods
    private IntPtr SetHook(LowLevelKeyboardProc proc)
    {
        using (Process curProcess = Process.GetCurrentProcess())
        using (ProcessModule curModule = curProcess.MainModule)
        {
            return SetWindowsHookEx(WH_KEYBOARD_LL, proc,
                GetModuleHandle(curModule.ModuleName), 0);
        }
    }

    private IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam)
    {
        //if (nCode >= 0 && wParam == (IntPtr)WM_KEYDOWN)
        if (nCode >= 0 && (wParam == (IntPtr)WM_KEYDOWN || wParam == (IntPtr)WM_SYSKEYDOWN))
        {
            int vkCode = Marshal.ReadInt32(lParam);
            WinForms.Keys key = (WinForms.Keys)vkCode;
            if (this.KeyDown != null)
                this.KeyDown(this, new KeyboardHookEventArgs(vkCode));
        }
        return CallNextHookEx(_hookID, nCode, wParam, lParam);
    }

    #endregion

    #region Destructor
    public void Dispose()
    {
        UnhookWindowsHookEx(_hookID);
    }
    #endregion
}

注册全局shell挂钩：

    public enum ShellEvents
    {
        HSHELL_WINDOWCREATED = 1,
        HSHELL_WINDOWDESTROYED = 2,
        HSHELL_ACTIVATESHELLWINDOW = 3,
        HSHELL_WINDOWACTIVATED = 4,
        HSHELL_GETMINRECT = 5,
        HSHELL_REDRAW = 6,
        HSHELL_TASKMAN = 7,
        HSHELL_LANGUAGE = 8,
        HSHELL_ACCESSIBILITYSTATE = 11
    }

    public class ShellHook
    {
        #region Events
        private delegate IntPtr ShellProc(int nCode, IntPtr wParam, IntPtr lParam);
        public delegate void HookEventHandler(object sender, ShellHookEventArgs e);
        public event HookEventHandler WindowActivated;
        #endregion

        #region Constants
        private const int WH_SHELL = 10;
        private ShellProc _proc = null;
        private static IntPtr _hookID = IntPtr.Zero;
        #endregion

        #region Imports
        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr SetWindowsHookEx(int idHook,
            ShellProc lpfn, IntPtr hMod, uint dwThreadId);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool UnhookWindowsHookEx(IntPtr hhk);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode,
            IntPtr wParam, IntPtr lParam);

        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr GetModuleHandle(string lpModuleName);

        [DllImport("user32.dll")]
        static extern int GetWindowText(IntPtr hWnd, StringBuilder text, int count);
        #endregion

        #region Fields
        #endregion

        #region Constructor
        public ShellHook()
        {
            _proc = new ShellProc(HookCallback); 
            _hookID = SetHook(_proc);
        }
        #endregion

        #region Methods
        private IntPtr SetHook(ShellProc proc)
        {
            using (Process curProcess = Process.GetCurrentProcess())
            using (ProcessModule curModule = curProcess.MainModule)
            {
                return SetWindowsHookEx(WH_SHELL, proc,
                    GetModuleHandle(curModule.ModuleName), 0);
            }
        }

        private IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam)
        {
            if (nCode >= 0 && wParam.Equals(ShellEvents.HSHELL_WINDOWACTIVATED))
            {
                string windowTitle = GetWindowTitle(wParam);
                if (this.WindowActivated != null)
                    this.WindowActivated(this, new ShellHookEventArgs(windowTitle));
            }
            return CallNextHookEx(_hookID, nCode, wParam, lParam);
        }

        private string GetWindowTitle(IntPtr hWnd)
        {
            const int nChars = 256;
            StringBuilder Buff = new StringBuilder(nChars);

            if (GetWindowText(hWnd, Buff, nChars) > 0)
            {
                return Buff.ToString();
            }
            return null;
        }
        #endregion

        #region Destructor
        public void Dispose()
        {
            UnhookWindowsHookEx(_hookID);
        }
        #endregion
    }

由于某种原因，键盘钩子工作，但shell钩子失败（SetWindowsHookEx返回0并且永远不会回调）。

任何想法为什么？

Answer 1

我想我会回答我自己的问题。来自pinvoke.net的引用解释了为什么......

但是，您无法在Microsoft .NET Framework中实现全局挂钩除了低级别的钩子。要安装全局钩子，钩子必须有一个本机动态链接库（DLL）导出将自己注入另一个需要有效，一致的函数才能调用的进程。这个需要DLL导出，.NET Framework不支持。管理代码没有函数指针的一致值的概念因为这些函数指针是构建的代理动态。

全局键盘钩子工作，但全局shell挂钩失败

1 个答案: