使用 WinAPI WH_CALLWNDPROC 挂钩时不调用回调方法

Question

我想在窗口移动时收到消息。

我开始编写一个简单的 C++ 控制台应用程序，它可以连接到 Windows 的默认记事本应用程序。 其中一部分包含以下代码设置钩子（不是全部三个，只有一个）

_hook = SetWindowsHookEx(WH_MOUSE, CallWndProc, _dllInstance, tid); //WORKS
_hook = SetWindowsHookEx(WH_KEYBOARD, CallWndProc, _dllInstance, tid); //WORKS
_hook = SetWindowsHookEx(WH_CALLWNDPROC, CallWndProc, _dllInstance, tid); //DOESNT WORK

所以基本上挂钩的过程是相同的，每种挂钩类型都使用相同的回调函数。 为什么它不适用于 WH_CALLWNDPROC？ 应用 WH_CALLWNDPROC 时，钩子和其他钩子一样成功，但它根本不起作用。

这是回调函数

// The callback function
LRESULT CALLBACK CallWndProc(int nCode, WPARAM wParam, LPARAM lParam) {
    std::cout << "callback " << counter++ << "\n";

    //This is a must
    return CallNextHookEx(_hook, nCode, wParam, lParam);
}

但是在设置这个钩子时永远不会调用 CallWndProc。

我什至尝试在 DLL 中调用 CallWndProc 函数，但这也不起作用，所以我将它完全从 DLL 中删除，现在它是一个空 DLL。即使它有效，对我来说也没用，因为我需要在我的应用程序中而不是在目标线程上处理消息。

任何提示？这是完整的代码

#include "Main.h"
#include <Windows.h>

#include <iostream>


/* Variable to store the HANDLE to the hook. Don't declare it anywhere else then globally
or you will get problems since every function uses this variable. */
HHOOK _hook;

// the dll instance
HINSTANCE _dllInstance;

//HOOKPROC _dllCallback;

int counter = 0;

// The callback function
LRESULT CALLBACK CallWndProc(int nCode, WPARAM wParam, LPARAM lParam) {
    std::cout << "callback " << counter++ << "\n";

    //This is a must
    return CallNextHookEx(_hook, nCode, wParam, lParam);
}

// This functions installs a hook to a window with given title
int InstallHook(const wchar_t* title) {

    /* 1. Get window handle of given title */
    std::wcout << "INFO: Getting window handle for \"" << title << "\"...\n";
    HWND hwnd = FindWindow(NULL, title);
    if (hwnd == NULL) {
        std::cout << "ERROR: Could not find target window.\n";
        return -1;
    }
     
    /* 2. Get ThreadID (TID) of the window handle */ 
    std::wcout << "INFO: Getting TheadID (TID) of \"" << title << "\"...\n";
    DWORD pid = NULL; // If we dont know -> NULL
    DWORD tid = GetWindowThreadProcessId(hwnd, &pid);
    if (tid == NULL) {
        std::cout << "ERROR: Could not find target window.\n";
        return -2;
    }

    /* 3. Load in the DLL */
    std::wcout << "INFO: Loading the DLL\n";
    _dllInstance = LoadLibrary(TEXT("winhooks_dll.dll"));
    if (_dllInstance == NULL) {
        std::cout << "ERROR: Could not load DLL...\n";
        return -3;
    }

    /* 3.5 Get Callback function from dll*/
    //_dllCallback = (HOOKPROC)GetProcAddress(_dllInstance, "_wmProcCallback@12");
    //if (_dllCallback == NULL) {
    //  std::cout << "ERROR: Could not get Callback function from dll instance\n";
    //  return -4;
    //}

    /* 4. Install the hook and set the handle */
    std::wcout << "INFO: Setting the hook...\n";
    _hook = SetWindowsHookEx(WH_MOUSE, CallWndProc, _dllInstance, tid); // The local callback version
    //_hook = SetWindowsHookEx(WH_CALLWNDPROCRET, _dllCallback, _dllInstance, tid); // The dll callback function
    if (_dllInstance == NULL) {
        std::cout << "ERROR: Could not set hook handle\n";
        return -5;
    }

    return 0;
}

int main() {

    const wchar_t* title = L"Untitled - Notepad";

    if (InstallHook(title) != 0) {
        std::wcout << "ERROR: Could not install hook on " << title << " last error -> " << GetLastError() << "\n";
        system("pause");
        return 1;
    }

    std::wcout << "SUCCESS: Hook is successfully installed on " << title << "\n";
    std::wcout << "Running message loop..." << std::endl;

    MSG msg;
    while (GetMessage(&msg, NULL, 0,0)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
}

Answer 1

首先，源平台（32位或64位）必须与目标平台匹配。（在我的64位机器上，记事本是64位的。）
其次，对于 DLL 中的钩子程序，不要通过 print 来验证它是否有效，与 std::out 相同。 DLL 无处打印其内容。以下代码使用文件流。

// The callback function
LRESULT CALLBACK CallWndProc(int nCode, WPARAM wParam, LPARAM lParam) {
    if (nCode == HC_ACTION)
    {
        if (wParam > 0)
        {
            std::cout << "sent by the current thread wParam=" << wParam;
        }
        CWPSTRUCT* s = (CWPSTRUCT*)lParam;

        //have no
        std::cout << " Index=" << nwinhooksdll++ << " s->message=" << s->message << " s->hwnd=" << s->hwnd << " s->wParam=" << s->wParam << " s->lParam=" << s->lParam << "\n";
        //MessageBox(NULL,L"CallWndProc",L"CALLBACK",0);

        //works
        myfile << " Index=" << nwinhooksdll++ << " s->message=" << s->message << " s->hwnd=" << s->hwnd << " s->wParam=" << s->wParam << " s->lParam=" << s->lParam << "\n";
    }

    //This is a must
    return CallNextHookEx(_hook, nCode, wParam, lParam);
}