为什么挂钩不能用于WH_KEYBOARD之类的高级钩子，虽然它与WH_KEYBOARD_LL一起工作正常，但是我能做些什么来成功实现WH_KEYBOARD钩子呢？ [英] why hooking doesn't work with high level hooks such as WH_KEYBOARD , although it works fine with WH_KEYBOARD_LL , what can I do to implement WH_KEYBOARD hook successfully ?

问题描述

这里是dll的代码

  //   dllmain.cpp：定义DLL应用程序的入口点。 
  #include  < span class =code-preprocessor>   stdafx.h 
   #include     dll.h 
  
  #pragma data_seg（。SHARE）
  HWND hWndServer = NULL; 
 HHOOK hhook = NULL; 
  #pragma data_seg（）
   #pragma comment（linker，/ section：.SARE， rws）
  
 HINSTANCE hinst = NULL; 
 
 
 
 BOOL APIENTRY DllMain（HMODULE hModule，
 DWORD ul_reason_for_call，
 LPVOID lpReserved 
）
 {
 FILE *文件; 
 fopen_s（& file，  c：\\Users \\keyur \\\ \\\\\\\\\\ ，  a +）; 
  switch （ul_reason_for_call）
 {
  case  DLL_PROCESS_ATTACH：
 fprintf（file，  dll attach \\\
）; 
  break ; 
  case  DLL_THREAD_ATTACH：
 fprintf（file，  thread attach \\\
）; 
  break ; 
  case  DLL_THREAD_DETACH：
 fprintf（file，  thread detach \\\
）; 
  break ; 
  case  DLL_PROCESS_DETACH：
 fprintf（file，  dll detach \\\
）; 
  break ; 
} 
  return  TRUE; 
} 
 
 
  __ declspec （ dllexport ）BOOL WINAPI setMyHook（HWND hWnd）
 {
  if （hWndServer！= NULL）
 返回错误; 
 hhook = SetWindowsHookEx（
 WH_KEYBOARD， //  这是问题 
（HOOKPROC）myhook，
 hinst，
  0 ）; 
  if （hhook！= NULL）
 { / *   success * /  
 hWndServer = hWnd; 
  return  TRUE; 
}  / *  成功* /  
 返回错误; 
} 
 
 
 静态 LRESULT CALLBACK myhook（ int  ncode，WPARAM wparam，LPARAM lparam）
 {
 FILE * file; 
 fopen_s（& file，  c：\\Users \\keyur \\\ \\ _doctop \\hook.txt，  a +）; 
 fprintf（file，  keystroked \\\
）; 
 
 fclose（档案）; 
  return  CallNextHookEx（hhook，ncode，wparam，lparam）; 
} 

这里是我的cpp文件，请忽略代码中的MyLowLevelHook

  #include   <   string.h  >  
   #include     C：\ Users \keyur \Desktop \keyur \HOOKING\dll\dll\dll.h 
  
 HHOOK hhook = NULL; 
 HWND hwnd; 
 
 LRESULT CALLBACK MyLowLevelHook（ int  nCode，WPARAM wParam，LPARAM lParam）
 {
  //   GetKeyNameText（lParam，（LPWSTR）缓冲区，20）;  
  //   _ strlwr（buffer）;  
 
 FILE * file; 
 fopen_s（& file，  c：\\Users \\keyur \\\ \\ _doctop \\hook.txt，  a +）; 
 fprintf（file，  keystroked \\\
）; 
 
 fclose（档案）; 
  return  CallNextHookEx（hhook，nCode，wParam，lParam）; 
} 
 
  int  main（）
 {
 MSG msg; 
 
 BOOL hook = setMyHook（hwnd）; 
 
  //   hhook = SetWindowsHookEx（WH_MOUSE_LL，myhook，NULL，NULL）;  
  if （hook == FALSE）
 {
 printf（  hook为null）; 
 getchar（）; 
} 
 
  while （！GetMessage（& msg，NULL，NULL，NULL））{
 TranslateMessage（ &安培; MSG）; 
 DispatchMessage（& msg）; 
} 
 
 UnhookWindowsHookEx（hhook）; 
} 

解决方案

我的猜测是，原因是你没有窗口你的申请。请参阅KeyboardProc回调文档



KeyboardProc回调 [ ^ ]。

它说只有当应用程序调用GetMessage或PeekMessage时才会调用钩子函数功能，并有一个键盘消息（WM_KEYUP或WM_KEYDOWN）待处理。



在您的情况下，没有窗口，因此没有消息要处理。



相反，低级事件在没有有效消息队列的情况下工作;每当生成键盘事件时它们都会被触发。



分辨率：在主函数中打开一个窗口，让该窗口获得焦点，然后一切都应该正常工作。

here is the code for dll

// dllmain.cpp : Defines the entry point for the DLL application.
#include "stdafx.h"
#include "dll.h"

#pragma data_seg(".SHARE")
HWND hWndServer = NULL;
HHOOK hhook=NULL;
#pragma data_seg()
#pragma comment("linker, /section:.SHARE,rws")

HINSTANCE hinst=NULL;



BOOL APIENTRY DllMain( HMODULE hModule,
                       DWORD  ul_reason_for_call,
                       LPVOID lpReserved
					 )
{
	FILE *file;
	fopen_s(&file,"c:\\Users\\keyur\\desktop\\temp.txt","a+");	
	switch (ul_reason_for_call)
	{
	case DLL_PROCESS_ATTACH:
		fprintf(file," dll attach \n");
		break;
	case DLL_THREAD_ATTACH:
		fprintf(file," thread attach \n");
		break;
	case DLL_THREAD_DETACH:
		fprintf(file," thread detach \n");
		break;
	case DLL_PROCESS_DETACH:
		fprintf(file," dll detach \n");
		break;
	}
	return TRUE;
}


__declspec(dllexport) BOOL WINAPI setMyHook(HWND hWnd)
  {
   if(hWndServer != NULL)
      return FALSE;
   hhook = SetWindowsHookEx(
                           WH_KEYBOARD,//here is the problem
                           (HOOKPROC)myhook,
                           hinst,
                           0);
   if(hhook != NULL)
     { /* success */
      hWndServer = hWnd;
      return TRUE;
     } /* success */
   return FALSE;
  }


static LRESULT CALLBACK myhook(int ncode,WPARAM wparam,LPARAM lparam)
{
	FILE *file;
	fopen_s(&file,"c:\\Users\\keyur\\desktop\\hook.txt","a+");	
	fprintf(file," keystroked \n");
	
	fclose(file);
	return CallNextHookEx(hhook , ncode ,wparam , lparam);
}

and here is my cpp file , please ignore the MyLowLevelHook in the code

#include <string.h>
#include "C:\Users\keyur\Desktop\keyur\HOOKING\dll\dll\dll.h"

HHOOK hhook = NULL;
HWND hwnd ;

LRESULT CALLBACK MyLowLevelHook ( int nCode , WPARAM wParam , LPARAM lParam)
{
	//GetKeyNameText(lParam,(LPWSTR)buffer,20);
	//_strlwr(buffer);
	
	FILE *file;
	fopen_s(&file,"c:\\Users\\keyur\\desktop\\hook.txt","a+");	
	fprintf(file," keystroked \n");
	
	fclose(file);
	return CallNextHookEx(hhook, nCode ,wParam , lParam);
}

int main()
{
    MSG msg;

	BOOL hook=setMyHook(hwnd);
	
	//hhook = SetWindowsHookEx(WH_MOUSE_LL, myhook , NULL,NULL);
	if(hook==FALSE)
	{
		printf("hook is null");
		getchar();
	}

    while(!GetMessage(&msg, NULL, NULL, NULL)) {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
	
    UnhookWindowsHookEx(hhook);
} 

解决方案

My guess would be that the reason is that you don't have a window in your application. See the documentation of KeyboardProc callback

KeyboardProc callback[^].
There it says that the hook function is only called "whenever an application calls the GetMessage or PeekMessage function and there is a keyboard message (WM_KEYUP or WM_KEYDOWN) to be processed".

In your case there is no window, and hence no message to be processed.

In contrast, the low level events work without a valid message queue; they are fired whenever the keyboard event is being generated.

Resolution: Open a window in your main function, let that window get the focus and then everything should work fine.

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