c++ - 错误C2440: 'type cast':无法从 'overloaded-function'转换为 'HOOKPROC'

我正在开发键盘记录器，这就是我得到的

Keylogger.h:

#pragma once
#include <stdio.h>
#include <windows.h>

class Keylogger
{
    KBDLLHOOKSTRUCT kbdStruct;
    BYTE keyState[256];
    WCHAR buffer[16];

public:
    HHOOK hKeyHook;

    Keylogger(void);
    ~Keylogger(void);
    LRESULT WINAPI KeyEvent(int nCode, WPARAM wParam, LPARAM lParam);
};

Keylogger.cpp:

#include "Keylogger.h"


Keylogger::Keylogger(void)
{
}


Keylogger::~Keylogger(void)
{
}

LRESULT WINAPI Keylogger::KeyEvent(int nCode, WPARAM wParam, LPARAM lParam)
{
    if( (nCode == HC_ACTION) && ((wParam == WM_SYSKEYDOWN) || (wParam == WM_KEYDOWN)) )
    {
        kbdStruct = *((KBDLLHOOKSTRUCT*)lParam);
        GetKeyboardState((PBYTE)&keyState);
        ToUnicode(kbdStruct.vkCode, kbdStruct.scanCode, (PBYTE)&keyState, (LPWSTR)&buffer, sizeof(buffer) / 2, 0);
        printf("%X\t%c\n", buffer[0], buffer[0]);
    }

    return CallNextHookEx(hKeyHook, nCode, wParam, lParam);
}

main.cpp:

#include "Keylogger.cpp"

int main(HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int nCmdShow)
{
    Keylogger kl = Keylogger();

    kl.hKeyHook = SetWindowsHookEx(WH_KEYBOARD_LL, (HOOKPROC) kl.KeyEvent, GetModuleHandle(NULL), 0);

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

    UnhookWindowsHookEx(kl.hKeyHook);
    return 0;
}

在下面的kl.hKeyHook = SetWindowsHookEx(WH_KEYBOARD_LL, (HOOKPROC) kl.KeyEvent, GetModuleHandle(NULL), 0);行上，我收到错误C2440:'type cast':无法从'overloaded-function'转换为'HOOKPROC'

有没有办法解决这个问题？

最佳答案

WinAPI主要是C编程接口(interface)，因此它不了解类。回调应该是静态的:

static LRESULT WINAPI KeyEvent(int nCode, WPARAM wParam, LPARAM lParam);

然后

kl.hKeyHook = SetWindowsHookEx(WH_KEYBOARD_LL, (HOOKPROC) Keylogger::KeyEvent, GetModuleHandle(NULL), 0);