/* DllPart。Dll */
#include 
#include 
#include 
#include 
typedef (WINAPI *MsgBoxType)(HWND,LPCWSTR,LPCWSTR,UINT); 
MsgBoxType oldMsg;  /*API原入口地址*/
DWORD APIAddress; /*存储API入口地址的地方的地址*/
int WINAPI  MyMessage(HWND hWnd ,LPCWSTR M1,LPCWSTR M2, UINT M3) {
 /* 这是用来替换的函数 */
 return oldMsg(hWnd,buf,M2,MB_OK);
}
const char szApp[] = "DllPart。
  dll";
HHOOK hHook; /*Hook的句柄*/
HMODULE hInst; /*DLL 模块句柄，用于SetWindowsHookEx函数*/
HWND hTarget; /*目标窗口句柄*/
/*DLL 入口*/
BOOL WINAPI DllMain(HINSTANCE inst, DWORD reason, LPVOID lpvReserved)
{
    hInst = inst;
    switch (reason) {
 case DLL_PROCESS_ATTACH:
     /*调试信息，表示DLL已经加载*/
     MessageBox(NULL,"DLL_PROCESS_ATTACH",szApp,MB_OK);
     break;
 case DLL_PROCESS_DETACH:
     /*调试信息，表示DLL已经卸载*/
     MessageBox(NULL,"DLL_PROCESS_DETACH",szApp,MB_OK);
     break;
    }
    return true;
}
/*显示GetLastError的信息*/
void showerr(const char *m) {
    char message[255];
    FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM,0,GetLastError()
 ,MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),message,255, 0);
    MessageBox(NULL,message,m,MB_OK);
}
//-----------------------
void UnHookApi() {
 /*卸载API Hook用*/
}
void HookApi() {
 /*加载API Hook同上面介绍的函数一样*/
}
//-----------------------
/*用于WH_GETMESSAGE的Hook Procedure*/
LRESULT CALLBACK GetMsgProc(int nCode,WPARAM wParam, LPARAM lParam) {
 if (nCode == HC_ACTION) {
     MSG *msg = (MSG *)lParam;
     if (msg->message == WM_CHAR) {
      if (msg->wParam == 'h') HookApi();
      if (msg->wParam == 'u') UnHookApi();
     }
 }
    return CallNextHookEx(hHook,nCode,wParam,lParam);
}
extern "C" __declspec(dllexport) SetAPIHook(HWND handle) {
    DWORD ThreadId = GetWindowThreadProcessId(handle, NULL);
    hTarget = handle;
    MessageBox(NULL, "Enabling CallWndProc Hook", szApp, MB_OK);
    hHook = SetWindowsHookEx(WH_GETMESSAGE,GetMsgProc,hInst,ThreadId); 
    if (hHook) {
 MessageBox(NULL,"Hook OK!", szApp, MB_OK);
    } else {
 showerr("SetWindowsHookEx");
    }
}
extern "C" __declspec(dllexport) UnHookAPIHook() {
    MessageBox(NULL, "Disenabling CallWndProc Hook", szApp, MB_OK);
    if (UnhookWindowsHookEx(hHook)) {
        MessageBox(NULL,"UnHook OK!", szApp, MB_OK); 
    } else {
 showerr("UnHookWindowsHookEx");
    }
}
。