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我使用此代碼GlobalKeyboardHook.cs鉤住鍵盤。「CallbackOnCollectedDelegate was detected」while trying to hook keyboard
我已經按照this post中的說明更改了所有指定的內容。現在，我的代碼如下所示：
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;
private static keyboardHookProc callbackDelegate;
#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");
callbackDelegate = new keyboardHookProc(hookProc);
hhook = SetWindowsHookEx(WH_KEYBOARD_LL, hookProc, hInstance, 0);
if (hhook == IntPtr.Zero) throw new System.ComponentModel.Win32Exception();
}
/// <summary>
/// Uninstalls the global hook
/// </summary>
public void unhook()
{
bool ok = UnhookWindowsHookEx(hhook);
if (!ok) throw new System.ComponentModel.Win32Exception();
callbackDelegate = null;
}
/// <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
}
}
此功能在我的程序掛接& DOWN鍵時，我的程序窗口是可見的。它在可見性變化時解除這些鍵。
private void AutoCompleteMenu_VisibleChanged(object sender, EventArgs e)
{
if (this.Visible == true)
{
if (hookFlag == 0)
{
try
{
gkh.hook();
gkh.HookedKeys.Add(Keys.Up);
gkh.HookedKeys.Add(Keys.Down);
gkh.KeyDown += new KeyEventHandler(gkh_KeyDown);
gkh.KeyUp += new KeyEventHandler(gkh_KeyUp);
}
catch (Exception)
{
MessageBox.Show("Cannot hook arrow keys! Please use mouse keys to select a word");
}
hookFlag = 1;
}
}
else
{
if (hookFlag == 1)
{
hookFlag = 0;
gkh.unhook();
}
}
}
這個代碼寫在程序初始化部分：
檢測CallbackOnCollectedDelegate消息：
globalKeyboardHook gkh = new globalKeyboardHook();不過，每當我的程序試圖鉤鍵我得到這個錯誤的回調是由 'CaretPosition！Utilities.globalKeyboardHook + keyboardHookProc :: Invoke'的垃圾收集代表製作 。 這可能會導致應用程序崩潰，損壞和數據丟失。當 將代理傳遞給非託管代碼時，它們必須由管理的應用程序保持活動狀態，直到它確保它們永遠不會被調用 。
請幫我解決這個問題。
脫鉤是否有任何機會，你Utilities.globalKeyboardHook類實例和應用程序生命週期，因此keyboardHookProc代表自毀？ – Tommi 2013-04-30 08:31:28
您想閱讀http://msdn.microsoft.com/en-us/library/system.gc.keepalive.aspx有關C＃垃圾回收器的KeepAlive方法的msdn文章 - 也許它可以幫助您解決問題。 – Dietz 2013-04-30 09:02:43