c# - 已经在C#中对垃圾收集的委托(delegate)进行了调用？

我一直在使用找到的这个 key 挂钩脚本，但是在程序中使用它几秒钟后，我仍然出现错误。错误消息说。已对垃圾回收的委托(delegate)'keylogger!Utilities.globalKeyboardHook + keyboardHookProc::Invoke'进行了调用。

我怎样才能解决这个问题？

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()
    {
        hook();
    }

    /// <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()
    {

        IntPtr hInstance = LoadLibrary("User32");
        hhook = SetWindowsHookEx(WH_KEYBOARD_LL, hookProc, hInstance, 0);
    }

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

    /// <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);
    #endregion
    }
}

globalKeyboardHook类:

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

namespace Utilities
{
/// <summary>
/// A class that manages a global low level keyboard hook
/// </summary>
class globalKeyboardHook : IDisposable
{

    private bool _disposed;

    #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()
    {
        hook();
        _disposed = false;
    }

    public void Dispose()
    {
        Dispose(true);

        // Use SupressFinalize in case a subclass
        // of this type implements a finalizer.
        GC.SuppressFinalize(this);
    }

    protected virtual void Dispose(bool disposing)
    {
        // If you need thread safety, use a lock around these
        // operations, as well as in your methods that use the resource.
        if (!_disposed)
        {
            if (disposing)
            {
                unhook();
            }

            // Indicate that the instance has been disposed.
            _disposed = true;
        }
    }

    /// <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()
    {
        Dispose();
    }
    #endregion

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

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

    /// <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);
    #endregion
    }
}

我使用IDisposable更新了代码。我可能对我应该做的事情很不满意，但仍然无法正常工作

最佳答案

问题是:

hhook = SetWindowsHookEx(WH_KEYBOARD_LL, hookProc, hInstance, 0);

只是用于以下目的的语法糖:

hhook = SetWindowsHookEx(WH_KEYBOARD_LL, new keyboardHookProc(hookProc), hInstance, 0);

因此keyboardHookProc对象只是本地对象，将被丢弃，因为SetWindowsHookEx在托管世界中实际上并没有采取任何行动。

要解决此问题，请在定义成员变量的顶部上方，再添加一个这样的变量:

IntPtr hhook = IntPtr.Zero
private keyboardHookProc hookProcDelegate;

然后将您的构造函数更改为:

public globalKeyboardHook()
{
    hookProcDelegate = hookProc;
    hook();
}

然后将hook()方法更改为:

public void hook()
{
    IntPtr hInstance = LoadLibrary("User32");
    hhook = SetWindowsHookEx(WH_KEYBOARD_LL, hookProcDelegate, hInstance, 0);
}

这样，您将使用存储为成员变量的委托(delegate)，只要您的globalKeyboardHook对象处于 Activity 状态，该代理就会处于 Activity 状态。