windows钩子的奇怪行为

Question

我一直在寻找在操作系统（Windows XP 32 位）中激活任何窗口时在 .NET Windows 应用程序中收到通知的可能性。在 CodeProject 上，我找到了使用全局系统挂钩的解决方案。

http://www.codeproject.com/Articles/18638/Using-Window-Messages-to-Implement-Global-System-H.

以下是此过程的简短摘要：

在非托管程序集（用 C++ 编写）中，实现了一个安装 WH_CBT 挂钩的方法。

bool InitializeCbtHook(int threadID, HWND destination) 
{ 
    if (g_appInstance == NULL) 
    { 
       return false; 
    }  

    if (GetProp(GetDesktopWindow(), " HOOK_HWND_CBT") != NULL) 
    { 
        SendNotifyMessage((HWND)GetProp(GetDesktopWindow(), "HOOK_HWND_CBT"), 
            RegisterWindowMessage("HOOK_CBT_REPLACED"),  0, 0); 
    } 

    SetProp(GetDesktopWindow(), " HOOK_HWND_CBT", destination); 


    hookCbt = SetWindowsHookEx(WH_CBT, (HOOKPROC)CbtHookCallback,     g_appInstance, threadID); 

    return hookCbt != NULL; 

} 

在回调方法（过滤函数）中，根据钩子类型窗口消息被发送到目标窗口。

static LRESULT CALLBACK CbtHookCallback(int code, WPARAM wparam, LPARAM lparam) 
{ 
    if (code >= 0) 
    { 
        UINT msg = 0; 

        if (code == HCBT_ACTIVATE) 
            msg = RegisterWindowMessage("HOOK_HCBT_ACTIVATE"); 
        else if (code == HCBT_CREATEWND) 
            msg = RegisterWindowMessage("HOOK_HCBT_CREATEWND"); 
        else if (code == HCBT_DESTROYWND) 
            msg = RegisterWindowMessage("HOOK_HCBT_DESTROYWND"); 
        else if (code == HCBT_MINMAX) 
            msg = RegisterWindowMessage("HOOK_HCBT_MINMAX"); 
        else if (code == HCBT_MOVESIZE) 
            msg = RegisterWindowMessage("HOOK_HCBT_MOVESIZE"); 
        else if (code == HCBT_SETFOCUS) 
            msg = RegisterWindowMessage("HOOK_HCBT_SETFOCUS"); 
        else if (code == HCBT_SYSCOMMAND) 
            msg = RegisterWindowMessage("HOOK_HCBT_SYSCOMMAND"); 

        HWND dstWnd = (HWND)GetProp(GetDesktopWindow(), HOOK_HWND_CBT"); 

        if (msg != 0) 
            SendNotifyMessage(dstWnd, msg, wparam, lparam); 
    } 

    return CallNextHookEx(hookCbt, code, wparam, lparam); 
} 

要在 .NET Windows 应用程序中使用此程序集，必须导入以下方法：

[DllImport("GlobalCbtHook.dll", CallingConvention = CallingConvention.Cdecl)] 
public static extern bool InitializeCbtHook (int threadID, IntPtr DestWindow);

[DllImport("GlobalCbtHook.dll", CallingConvention = CallingConvention.Cdecl)]
public static extern void UninitializeCbtHook(int hookType);

调用InitializeCbtHook后，从GlobalCbtHook.dll收到的消息可以在：

protected override void WndProc(ref Message msg) 

消息必须通过调用在程序集和应用程序中注册 RegisterWindowMessage.

[DllImport("user32.dll")]
private static extern int RegisterWindowMessage(string lpString);

此实现工作正常。但在大多数情况下，当我激活 Microsoft Office Outlook 在我最小化 Outlook 或激活其他窗口后，我的 .NET 应用程序会收到激活事件。起初我认为我的 .NET 包装器是问题的原因。但是在我使用上述链接的来源之后，我可以识别出相同的行为。 我实际的解决方法是使用WH_SHELL 钩子。我知道WH_CBT 和WH_SHELL 钩子之间的一个区别是，当使用WH_CBT 钩子时，可以通过不调用CallNextHookEx 方法来中断过滤器函数链。这会在我的问题中发挥作用吗？ 请提供帮助。

Answer 1

显然挂钩在 Outlook 的情况下不起作用 - 其他 microsoft 产品（word、power point ...）呢？？

但是，为什么要上钩？即使激活了 Outlook，这个小类也可以工作

using System;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace WindowsMonitor
{
    public class ActiveWindowChangedEventArgs : EventArgs
    {
        public IntPtr CurrentActiveWindow { get; private set; }
        public IntPtr LastActiveWindow { get; private set; }

        public ActiveWindowChangedEventArgs(IntPtr lastActiveWindow, IntPtr currentActiveWindow)
        {
            this.LastActiveWindow = lastActiveWindow;
            this.CurrentActiveWindow = currentActiveWindow;
        }
    }

    public delegate void ActiveWindowChangedEventHandler(object sender, ActiveWindowChangedEventArgs e);

    public class ActiveWindowMonitor
    {
        [DllImport("user32.dll")]
        private static extern IntPtr GetForegroundWindow();

        private Timer monitorTimer;

        public IntPtr ActiveWindow { get; private set; }
        public event ActiveWindowChangedEventHandler ActiveWindowChanged;

        public ActiveWindowMonitor()
        {
            this.monitorTimer = new Timer();
            this.monitorTimer.Tick += new EventHandler(monitorTimer_Tick);
            this.monitorTimer.Interval = 10;
            this.monitorTimer.Start();
        }

        private void monitorTimer_Tick(object sender, EventArgs e)
        {
            CheckActiveWindow();
        }

        private void CheckActiveWindow()
        {
            IntPtr currentActiveWindow = GetForegroundWindow();
            if (this.ActiveWindow != currentActiveWindow)
            {
                IntPtr lastActiveWindow = this.ActiveWindow;
                this.ActiveWindow = currentActiveWindow;

                OnActiveWindowChanged(lastActiveWindow, this.ActiveWindow);
            }
        }

        protected virtual void OnActiveWindowChanged(IntPtr lastActiveWindow, IntPtr currentActiveWindow)
        {
            ActiveWindowChangedEventHandler temp = ActiveWindowChanged;
            if (temp != null)
            {
                temp.Invoke(this, new ActiveWindowChangedEventArgs(lastActiveWindow, currentActiveWindow));
            }
        }
    }
}

用法

    public void InitActiveWindowMonitor()
    {
        WindowsMonitor.ActiveWindowMonitor monitor = new WindowsMonitor.ActiveWindowMonitor();
        monitor.ActiveWindowChanged += new WindowsMonitor.ActiveWindowChangedEventHandler(monitor_ActiveWindowChanged);
    }

    private void monitor_ActiveWindowChanged(object sender, WindowsMonitor.ActiveWindowChangedEventArgs e)
    {
        //ouh a window got activated
    }