计时器上的低级键盘钩

时间:2011-04-18 16:43:06

标签: c# keyboard-hook

我有一个键盘钩子,可以拦截键并输出一个随机字母。我想要做的是设置一个计时器,让键盘在一分钟后解开,然后在另一分钟内自行备份。所以第一部分起作用,它在开始时挂起,一分钟后它解开,但后来再也没有连接起来。我怎么能在脱钩后让它重新挂钩?

这是钩子代码:

using System;
using System.Collections.Generic;
using System.Text;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace Utilities {
/// <summary>
/// A class that manages a global low level keyboard hook
/// </summary>
class globalKeyboardHook {
    #region Constant, Structure and Delegate Definitions
    /// <summary>
    /// defines the callback type for the hook
    /// </summary>
    public delegate int keyboardHookProc(int code, int wParam, ref keyboardHookStruct lParam);

    public struct keyboardHookStruct {
        public int vkCode;
        public int scanCode;
        public int flags;
        public int time;
        public int dwExtraInfo;
    }

    const int WH_KEYBOARD_LL = 13;
    const int WM_KEYDOWN = 0x100;
    const int WM_KEYUP = 0x101;
    const int WM_SYSKEYDOWN = 0x104;
    const int WM_SYSKEYUP = 0x105;

    #endregion

    #region Instance Variables
    /// <summary>
    /// The collections of keys to watch for
    /// </summary>
    public List<Keys> HookedKeys = new List<Keys>();
    /// <summary>
    /// Handle to the hook, need this to unhook and call the next hook
    /// </summary>
    IntPtr hhook = IntPtr.Zero;
    #endregion

    #region Events
    /// <summary>
    /// Occurs when one of the hooked keys is pressed
    /// </summary>
    public event KeyEventHandler KeyDown;
    /// <summary>
    /// Occurs when one of the hooked keys is released
    /// </summary>
    public event KeyEventHandler KeyUp;
    #endregion

    #region Constructors and Destructors
    /// <summary>
    /// Initializes a new instance of the <see cref="globalKeyboardHook"/> class and installs the keyboard hook.
    /// </summary>
    public globalKeyboardHook() {

    }



    /// <summary>
    /// Releases unmanaged resources and performs other cleanup operations before the
    /// <see cref="globalKeyboardHook"/> is reclaimed by garbage collection and uninstalls the keyboard hook.
    /// </summary>
    ~globalKeyboardHook() {
        unhook();
    }
    #endregion

    #region Public Methods
    /// <summary>
    /// Installs the global hook
    /// </summary>
    public void hook() {
        _hookProc = new keyboardHookProc(hookProc);
        IntPtr hInstance = LoadLibrary("User32");
        hhook = SetWindowsHookEx(WH_KEYBOARD_LL, hookProc, hInstance, 0);
    }

    /// <summary>
    /// Uninstalls the global hook
    /// </summary>
    public void unhook() {
        UnhookWindowsHookEx(hhook);
        hhook = IntPtr.Zero;
    }

    /// <summary>
    /// The callback for the keyboard hook
    /// </summary>
    /// <param name="code">The hook code, if it isn't >= 0, the function shouldn't do anyting</param>
    /// <param name="wParam">The event type</param>
    /// <param name="lParam">The keyhook event information</param>
    /// <returns></returns>
    public int hookProc(int code, int wParam, ref keyboardHookStruct lParam) {
        if (code >= 0) {
            Keys key = (Keys)lParam.vkCode;
            if (HookedKeys.Contains(key)) {
                KeyEventArgs kea = new KeyEventArgs(key);
                if ((wParam == WM_KEYDOWN || wParam == WM_SYSKEYDOWN) && (KeyDown != null)) {
                    KeyDown(this, kea) ;
                } else if ((wParam == WM_KEYUP || wParam == WM_SYSKEYUP) && (KeyUp != null)) {
                    KeyUp(this, kea);
                }
                if (kea.Handled)
                    return 1;
            }
        }
        return CallNextHookEx(hhook, code, wParam, ref lParam);
    }
    #endregion

    #region DLL imports
    /// <summary>
    /// Sets the windows hook, do the desired event, one of hInstance or threadId must be non-null
    /// </summary>
    /// <param name="idHook">The id of the event you want to hook</param>
    /// <param name="callback">The callback.</param>
    /// <param name="hInstance">The handle you want to attach the event to, can be null</param>
    /// <param name="threadId">The thread you want to attach the event to, can be null</param>
    /// <returns>a handle to the desired hook</returns>
    [DllImport("user32.dll")]
    static extern IntPtr SetWindowsHookEx(int idHook, keyboardHookProc callback, IntPtr hInstance, uint threadId);

    /// <summary>
    /// Unhooks the windows hook.
    /// </summary>
    /// <param name="hInstance">The hook handle that was returned from SetWindowsHookEx</param>
    /// <returns>True if successful, false otherwise</returns>
    [DllImport("user32.dll")]
    static extern bool UnhookWindowsHookEx(IntPtr hInstance);

    /// <summary>
    /// Calls the next hook.
    /// </summary>
    /// <param name="idHook">The hook id</param>
    /// <param name="nCode">The hook code</param>
    /// <param name="wParam">The wparam.</param>
    /// <param name="lParam">The lparam.</param>
    /// <returns></returns>
    [DllImport("user32.dll")]
    static extern int CallNextHookEx(IntPtr idHook, int nCode, int wParam, ref keyboardHookStruct lParam);

    /// <summary>
    /// Loads the library.
    /// </summary>
    /// <param name="lpFileName">Name of the library</param>
    /// <returns>A handle to the library</returns>
    [DllImport("kernel32.dll")]
    static extern IntPtr LoadLibrary(string lpFileName);

    keyboardHookProc _hookProc;

    #endregion
}
}

以下是该应用程序的切入点:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using Utilities;
using System.Timers;

namespace KeyRemapWindowsForm
{
static class Program
{
    static bool _isHookActive = true;
    static globalKeyboardHook gkh  = new globalKeyboardHook();
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {
        System.Timers.Timer HookTimer = new System.Timers.Timer(60000);
        HookTimer.Elapsed += new ElapsedEventHandler(HookTimer_Elapsed);
        HookTimer.Start();

        Begin();
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run();
        GC.KeepAlive(HookTimer);
    }

    // Specify what you want to happen when the Elapsed event is 
    // raised.
    static void HookTimer_Elapsed(object source, ElapsedEventArgs e)
    {
        if (_isHookActive)
        {
            End();
        }
        else
        {
            Begin();
        }
    }

    static void Begin()
    {
        gkh = new globalKeyboardHook();
        gkh.hook();
        gkh.HookedKeys.Add(Keys.A);
        gkh.HookedKeys.Add(Keys.B);
        gkh.KeyDown += new KeyEventHandler(gkh_KeyDown);
        gkh.KeyUp += new KeyEventHandler(gkh_KeyUp);
        _isHookActive = true;
    }

    static void End()
    {
        gkh.HookedKeys.Clear();
        gkh.KeyDown -= new KeyEventHandler(gkh_KeyDown);
        gkh.KeyUp -= new KeyEventHandler(gkh_KeyUp);
        gkh.unhook();
        _isHookActive = false;
    }

    static void gkh_KeyUp(object sender, KeyEventArgs e)
    {
        SendKeys.Send(((KeyboardKeys)GetRandomKeyCode()).ToString());
        e.Handled = true;
    }

    static void gkh_KeyDown(object sender, KeyEventArgs e)
    {            
        e.Handled = true;
    } 

    static int GetRandomKeyCode()
    {
        int RandomNum = 0;
        while(RandomNum == 0)
        {
            Random RanNum = new Random();
            RandomNum = RanNum.Next(65, 90);

            switch(RandomNum)
            {
                case 68:
                case 69:
                case 86:
                RandomNum = 0;
                    break;
                default:
                    break;
            }

        }

        return RandomNum;
    }
}

public enum KeyboardKeys
{
    /// <summary>
    /// The A key.
    /// </summary>
    A = 65,
    /// <summary>
    /// The B key.
    /// </summary>
    B = 66,
    /// <summary>
    /// The C key.
    /// </summary>
    C = 67,
    /// <summary>
    /// The D key.
    /// </summary>
    D = 68,
    /// <summary>
    /// The E key.
    /// </summary>
    E = 69,
    /// <summary>
    /// The F key.
    /// </summary>
    F = 70,
    /// <summary>
    /// The G key.
    /// </summary>
    G = 71,
    /// <summary>
    /// The H key.
    /// </summary>
    H = 72,
    /// <summary>
    /// The I key.
    /// </summary>
    I = 73,
    /// <summary>
    /// The J key.
    /// </summary>
    J = 74,
    /// <summary>
    /// The K key.
    /// </summary>
    K = 75,
    /// <summary>
    /// The L key.
    /// </summary>
    L = 76,
    /// <summary>
    /// The M key.
    /// </summary>
    M = 77,
    /// <summary>
    /// The N key.
    /// </summary>
    N = 78,
    /// <summary>
    /// The O key.
    /// </summary>
    O = 79,
    /// <summary>
    /// The P key.
    /// </summary>
    P = 80,
    /// <summary>
    /// The Q key.
    /// </summary>
    Q = 81,
    /// <summary>
    /// The R key.
    /// </summary>
    R = 82,
    /// <summary>
    /// The S key.
    /// </summary>
    S = 83,
    /// <summary>
    /// The T key.
    /// </summary>
    T = 84,
    /// <summary>
    /// The U key.
    /// </summary>
    U = 85,
    /// <summary>
    /// The V key.
    /// </summary>
    V = 86,
    /// <summary>
    /// The W key.
    /// </summary>
    W = 87,
    /// <summary>
    /// The X key.
    /// </summary>
    X = 88,
    /// <summary>
    /// The Y key.
    /// </summary>
    Y = 89,
    /// <summary>
    /// The Z key.
    /// </summary>
    Z = 90
}
}
编辑:所以我接受了Jonathan.Peppers的建议,并在keydown事件中检查了isActive,这就像它打开和关闭一样。现在我遇到了一个新问题。在我输入一段时间之后,我得到一个InvalidOperationException,其原因是“Queue Empty”,并且在我输入时运行正常时不确定为什么它会被清空。我单独留下了键盘钩子代码,但将应用程序入口点代码更新为以下内容:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Forms;
using Utilities;
using System.Timers;

namespace KeyRemapWindowsForm
{
static class Program
{
    static bool _isHookActive = true;
    static globalKeyboardHook gkh  = new globalKeyboardHook();

    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    [STAThread]
    static void Main()
    {
        System.Timers.Timer HookTimer = new System.Timers.Timer(10000);
        HookTimer.Elapsed += new ElapsedEventHandler(HookTimer_Elapsed);
        HookTimer.Start();

        Application.ApplicationExit += new EventHandler(OnApplicationExit);

        gkh.hook();

        gkh.HookedKeys.Add(Keys.S);
        gkh.HookedKeys.Add(Keys.E);

        gkh.KeyDown += new KeyEventHandler(gkh_KeyDown);
        gkh.KeyUp += new KeyEventHandler(gkh_KeyUp);
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        Application.Run();
        GC.KeepAlive(HookTimer);
    }

    static void OnApplicationExit(object sender, EventArgs e)
    {
        gkh.unhook();
    }

    static void HookTimer_Elapsed(object source, ElapsedEventArgs e)
    {
        if (_isHookActive)
        {
            _isHookActive = false;
        }
        else
        {
            _isHookActive = true;
        }
    }        

    static void gkh_KeyUp(object sender, KeyEventArgs e)
    {
        try
        {
            if (_isHookActive)
            {
                e.Handled = true;
            }
        }
        catch 
        {
            gkh.unhook();
            Application.Exit();
        }
    }

    static void gkh_KeyDown(object sender, KeyEventArgs e)
    {
        try
        {
            if (_isHookActive)
            {
                SendKeys.Send(((Keys)new Random().Next(65, 90)).ToString());
                e.Handled = true;
            }
        }
        catch
        {
            gkh.unhook();
            Application.Exit();
        }
    } 
}
}

编辑:堆栈跟踪我输入一段时间后从上面的代码中得到。

在System.Collections.Queue.Dequeue()    在System.Windows.Forms.SendKeys.SendInput(Byte [] oldKeyboardState,Queue previousEvents)    在System.Windows.Forms.SendKeys.Send(字符串键,控件控件,布尔等待)    在System.Windows.Forms.SendKeys.Send(String keys)    在KeyRemapWindowsForm.Program.gkh_KeyDown(Object sender,KeyEventArgs e)中的C:\ Demos \ KeyRemapWindowsForm \ Program.cs:第79行

2 个答案:

答案 0 :(得分:1)

我一直在争论一个非常类似的问题所以我正在添加我发现的东西来帮助其他人解决问题。

问题是创建钩子的线程。 默认情况下,System.Timers.Timer类将在线程池上创建一个线程,而不是主UI线程。如果这个帖子去了,你的钩子也是如此。

您需要确保它在不会消失的线程上调用的计时器事件。 你可以: 使用.SynchronizingObject属性确保在与指定对象相同的线程中进行调用。

或者你可以自己编组,如果你把这样的东西放在你的计时器事件之上:

this.InvokeCatchDisposedException(new MethodInvoker(() => HookTimer_Elapsed(sender, e)));
            return;

这是一个链接,用于描述我发现有用的.net计时器之间的差异。 https://msdn.microsoft.com/en-us/magazine/cc164015.aspx

答案 1 :(得分:0)

为什么不连续留下钩子?

您可以切换钩子,不要使用计时器修改按键。在你的gkh_KeyUp和gkh_KeyDown方法中添加一个if(_hookEnabled)。

我认为设置钩子无论如何都会是一项昂贵的操作。