如何用C#结合user32.dll监听进程内嵌套窗口的尺寸变更事件

你的代码核心问题在于SetWinEventHook参数误用，以及缺少对目标子窗口的过滤判断，以下是具体修复方案：

关键问题分析 #

1. SetWinEventHook的第三个参数hmodWinEventProc被错误传入了窗口句柄，该参数仅在钩子函数位于外部DLL时才需要传入模块句柄，本地进程内的钩子应传入IntPtr.Zero。
2. 未在回调中过滤目标窗口，导致所有窗口的MOVESIZEEND事件都被触发，只捕获到主窗口是因为主窗口的事件更显眼。

修改后的代码 #

class Win32WindowEvents
{
    // 确保EventTypes枚举值正确：EVENT_SYSTEM_MOVESIZEEND = 0x000B
    private enum EventTypes : uint
    {
        EVENT_SYSTEM_MOVESIZEEND = 0x000B
    }

    private enum WinHookParameter : uint
    {
        OUTOFCONTEXT = 0x0000
    }

    [DllImport("user32.dll")]
    static extern IntPtr SetWinEventHook(uint eventMin, uint eventMax, IntPtr hmodWinEventProc, WinEventDelegate lpfnWinEventProc, uint idProcess, uint idThread, uint dwFlags);

    [DllImport("user32.dll")]
    static extern bool UnhookWinEvent(IntPtr hWinEventHook);

    // 补充WinEventDelegate定义（原代码可能遗漏）
    private delegate void WinEventDelegate(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime);

    private Win32Window Window_toListen;
    private IntPtr _resizeHook;
    private IntPtr _reorderHook;
    private WinEventDelegate _resizeProc;
    private WinEventDelegate _reorderProc;
    private uint timelogged; // 补充变量定义

    // 假设Resizing是一个外部事件或方法
    public event Action<Process, Win32Window, EventTypes> Resizing;

    public Win32WindowEvents(Win32Window window)
    {
        StopListening();
        _resizeProc = new WinEventDelegate(WinEventProc_Resizing);
        _reorderProc = new WinEventDelegate(WinEventProc_Reordering);

        Window_toListen = window;

        // 获取目标窗口的进程ID和线程ID（可选，缩小监听范围）
        uint processId = 0;
        uint threadId = GetWindowThreadProcessId(window.hWnd, out processId);

        // 修正SetWinEventHook参数：hmodWinEventProc传IntPtr.Zero，指定进程/线程缩小监听范围
        _resizeHook = SetWinEventHook(
            (uint)EventTypes.EVENT_SYSTEM_MOVESIZEEND,
            (uint)EventTypes.EVENT_SYSTEM_MOVESIZEEND,
            IntPtr.Zero, // 本地钩子，模块句柄为0
            _resizeProc,
            processId, // 目标窗口所属进程ID
            threadId,  // 目标窗口所属线程ID
            (uint)WinHookParameter.OUTOFCONTEXT
        );
    }

    private void WinEventProc_Resizing(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
    {
        // 关键：只处理目标子窗口的事件
        if (hwnd != Window_toListen.hWnd)
            return;

        if (Math.Abs(timelogged - dwmsEventTime) < 1000) 
            return;
            
        timelogged = dwmsEventTime;
        Resizing?.Invoke(Window_toListen.Process, Window_toListen, (EventTypes)eventType);
    }

    private void WinEventProc_Reordering(IntPtr hWinEventHook, uint eventType, IntPtr hwnd, int idObject, int idChild, uint dwEventThread, uint dwmsEventTime)
    {
        // 同理，需要时添加目标窗口过滤
    }

    public void StopListening()
    {
        // 卸载所有钩子，避免资源泄漏
        if (_resizeHook != IntPtr.Zero)
        {
            UnhookWinEvent(_resizeHook);
            _resizeHook = IntPtr.Zero;
        }
        if (_reorderHook != IntPtr.Zero)
        {
            UnhookWinEvent(_reorderHook);
            _reorderHook = IntPtr.Zero;
        }
    }

    // 补充获取窗口进程/线程ID的API
    [DllImport("user32.dll")]
    static extern uint GetWindowThreadProcessId(IntPtr hWnd, out uint lpdwProcessId);
}

额外说明 #

• 补充了GetWindowThreadProcessId来获取目标窗口的进程和线程ID，传入SetWinEventHook可以缩小监听范围，避免处理无关事件，提升性能。
• 在回调中增加了hwnd != Window_toListen.hWnd的判断，确保只响应目标子窗口的尺寸变更事件。
• 修正了StopListening方法，确保所有钩子都被正确卸载，防止资源泄漏。
• 补充了WinEventDelegate的定义（原代码可能遗漏，否则编译会报错）。

内容的提问来源于stack exchange，提问作者Wiley Ng