实现功能：在现有DLL程序中向特定的EXE窗口中发送模拟键盘的消息
　　　　  使用API根据窗口标题递归查找特定的窗口句柄，之后模拟调用。

注意：keybd_event函数不能在VS下使用，所以用SendInput代替使用：

 int SelfFindWindows(HWND hMainWnd, char* lpName, BYTE keyvalue)

 {

     HWND hChildWnd = GetWindow(hMainWnd, GW_CHILD); 

     while (hChildWnd != NULL)

     {

         char lpChildString[] ={};

         GetWindowText(hChildWnd, lpChildString, sizeof(lpChildString)); 

         if (strstr(lpChildString, lpName))

         {

             SetForegroundWindow(hChildWnd);

             SetFocus(hChildWnd); 

             /*

             keybd_event(keyvalue, 0, 0, 0);

             keybd_event(keyvalue, 0, KEYEVENTF_KEYUP, 0);

             */

             INPUT input[];

             memset(input, , sizeof(input));

             //按下 向下方向键

             input[].ki.wVk = keyvalue;

             input[].type = INPUT_KEYBOARD;

             //松开 向下方向键

             input[].ki.wVk = keyvalue;

             input[].type = INPUT_KEYBOARD;

             input[].ki.dwFlags = KEYEVENTF_KEYUP;

             //该函数合成键盘事件和鼠标事件，用来模拟鼠标或者键盘操作。事件将被插入在鼠标或者键盘处理队列里面

             SendInput(, input, sizeof(INPUT));

             return ;

         } 

         if (GetWindow(hChildWnd, GW_CHILD))

         {

             if (SelfFindWindows(hChildWnd, lpName, keyvalue))

             {

                 return ;

             }

         }

     else

         hChildWnd = GetWindow(hChildWnd, GW_HWNDNEXT);

     } 

     return ;

 } 

 int SendKeyEventToEXE()

 {

     HWND hDesk = GetDesktopWindow();

     HWND hWnd = GetWindow(hDesk, GW_CHILD); 

     while (hWnd != NULL)

     {

         char lpString[] ={};

         GetWindowText(hWnd, lpString, sizeof(lpString)); 

         if (strstr(lpString, "Foxit Reader"))

         {

             SelfFindWindows(hWnd, "Reader", VK_NEXT);    

             return ;

         } 

         hWnd = GetWindow(hWnd, GW_HWNDNEXT);

     }

     return ;

 }