按Enter键以导出“键盘挂钩”消息

问题描述

我已经编写了一个程序来获取键盘挂钩。我想要的是，当用户按下Enter键时，应该从函数中返回我存储在exportMsg中的键入文本，例如：“ hello world”。

我想制作一个dll并导出exportMsg。

这是我的代码。预先感谢。

#include <Windows.h>
#include <stdio.h>
#include <iostream> 
LRESULT CALLBACK KeyboardProc(int nCode,WParaM wParam,LParaM lParam); 
HHOOK keyboardHook;
HWND prevWindow;
std::string exportMsg=""; 
int main()
{
    keyboardHook = SetwindowsHookEx(WH_KEYBOARD_LL,KeyboardProc,0);
    MSG msg{ 0 };
    while (GetMessage(&msg,NULL,0) != 0);
    UnhookWindowsHookEx(keyboardHook);
    return 0;
} 
LRESULT CALLBACK KeyboardProc(int nCode,LParaM lParam)
{
    wchar_t title[256];
    HWND fwindow = GetForegroundWindow();
    PKBDLLHOOKSTRUCT key = (PKBDLLHOOKSTRUCT)lParam;
    //a key was pressed
    if (wParam == WM_KEYDOWN && nCode == HC_ACTION )
    { 
        //return if enter pressed
        if (key->vkCode == '\r')
        {  
            std::cout << exportMsg << std::endl;
        }
        else
        {
            exportMsg.push_back(key->vkCode);
        }
    }
    return CallNextHookEx(keyboardHook,nCode,wParam,lParam);
}

解决方法

由于std::cin在 Unity 中不起作用，我需要使用键盘钩通过QR Code Scanner Machine扫描qrCode并将扫描的字符串发送到{{1} }。

该算法捕获按键并在按下Enter键时返回字符串。

我的DLL代码如下：

头文件：

Unity

源文件：

LRESULT CALLBACK KeyboardProc(int nCode,WPARAM wParam,LPARAM lParam);
HHOOK keyboardHook;
HWND prevWindow;
std::string exportMsg = "";

QRCODEREADER_EXPORTS_API void StartHook(char* str,int strlen);

dllmain：

QRCODEREADER_EXPORTS_API void StartHook(char* str,int strlen)
{ 
    string result;
    cout << "please scan the QR code!!!\n";
    //std::cin >> result; 
    exportMsg.clear();

    HHOOK keyboardHook = SetWindowsHookEx(WH_KEYBOARD_LL,KeyboardProc,GetModuleHandle(NULL),0);
    if (!keyboardHook) {
        std::cout << "Failed to hook keyboard\n";
    }
    else {
        MSG msg{ 0 };
        while (GetMessage(&msg,NULL,0) != 0);
         
        result = exportMsg;
        cout << "your data: " << result << "\n";

        result = result.substr(0,strlen);
        //str = new char[result.length()];
        std::copy(result.begin(),result.end(),str);
        str[min(strlen - 1,(int)result.size())] = 0;
    } 
     
    std::cout << "Quitting...\n"; 
    UnhookWindowsHookEx(keyboardHook); 
}
LRESULT CALLBACK KeyboardProc(int nCode,LPARAM lParam)
{
    HWND fwindow = GetForegroundWindow();
    PKBDLLHOOKSTRUCT key = (PKBDLLHOOKSTRUCT)lParam;
    //a key was pressed
    if (wParam == WM_KEYDOWN && nCode == HC_ACTION)
    {
        //return if enter pressed
        if (key->vkCode == '\r')
        {
            std::cout << exportMsg << std::endl;
            PostQuitMessage(0); 
            UnhookWindowsHookEx(keyboardHook);
        }
        else
        {
            exportMsg.push_back(key->vkCode);
        }
    }
    return CallNextHookEx(keyboardHook,nCode,wParam,lParam);
}

,

我建议您使用自定义消息来实现此功能。

您可以在DLL中创建自定义消息，然后按ENTER键，将消息发送到调用DLL的进程，然后将所需的字符串作为参数传递。

这是.dll示例：

#include "pch.h"
#include <windows.h>
#include <iostream>
#include <string>
HHOOK _k_hook;
std::string exportMsg = "";
#define WM_STRING WM_APP+1

LRESULT __stdcall k_Callback1(int nCode,LPARAM lParam)
{
    wchar_t title[256];
    PKBDLLHOOKSTRUCT key = (PKBDLLHOOKSTRUCT)lParam;
    //a key was pressed
    if (wParam == WM_KEYDOWN && nCode == HC_ACTION)
    {
        //return if enter pressed
        if (key->vkCode == '\r')
        {
            char temp[1024];
            strcpy_s(temp,1024,exportMsg.c_str());
            PostThreadMessage(GetCurrentThreadId(),WM_STRING,(WPARAM)(temp),NULL);
            exportMsg.clear();
        }
        else
        {
            exportMsg.push_back(key->vkCode);
        }
    }

    return CallNextHookEx(NULL,lParam);
}


BOOL APIENTRY DllMain( HMODULE hModule,DWORD  ul_reason_for_call,LPVOID lpReserved
                     )
{
    HWINEVENTHOOK hHook = 0;

    switch (ul_reason_for_call)
    {
    case DLL_PROCESS_ATTACH:
        _k_hook = SetWindowsHookExA(WH_KEYBOARD_LL,k_Callback1,0);
        break;
    case DLL_THREAD_ATTACH:
    case DLL_THREAD_DETACH:
    case DLL_PROCESS_DETACH:
        if(hHook)
            UnhookWinEvent(hHook);
        break;
    }
    return TRUE;
}

然后，由于使用SetWindowsHookExA，因此在调用DLL时必须具有消息队列，以便在调用时可以根据自定义消息获取相应的内容。

您可以参考以下代码：

#include <iostream>
#include <windows.h>

#define WM_STRING WM_APP+1

using namespace std;

int main(int argc,const char* argv[])
{
    string s = "";
    HINSTANCE hDLL = LoadLibrary("Dll1.dll");
    if (hDLL == nullptr)
    {
        cout << "DLL NOT FOUND" << endl;
        return -1;
    }
    MSG msg{ 0 };
    while (GetMessage(&msg,0) != 0)
    {
        if (msg.message == WM_STRING)
        {
            s = (char *)msg.wParam;
            cout << s << endl;
        }
    }

    return 0;
}

因此，当您按Enter键时，您可以在呼叫站点获得相应的字符串。

输出（当我按“ HELLOWORLD” + ENTER时）：