HOWTO: Provide Your Own Window Class Name for an MFC Dialog Box

HOWTO:   Provide   Your   Own   Window   Class   Name   for   an   MFC   Dialog   Box    
   
  Q251059  
   
   
  --------------------------------------------------------------------------------  
  The   information   in   this   article   applies   to:  
   
  The   Microsoft   Foundation   Classes   (MFC),   included   with:  
  Microsoft   Visual   C++,   32-bit   Enterprise   Edition,   version   5.0    
  Microsoft   Visual   C++,   32-bit   Professional   Edition,   version   5.0    
  Microsoft   Visual   C++,   32-bit   Enterprise   Edition,   version   6.0    
  Microsoft   Visual   C++,   32-bit   Professional   Edition,   version   6.0    
  Microsoft   Visual   C++,   32-bit   Learning   Edition,   version   6.0  
   
  --------------------------------------------------------------------------------  
   
   
  SUMMARY  
  This   article   shows   you   how   to   provide   your   own   Window   Class   Name   for   a   dialog   box   created   in   an   MFC-based   application.    
   
  You   may   encounter   this   need   when   you   try   to   limit   your   dialog-based   MFC   application   to   a   single   instance.    
   
   
   
  MORE   INFORMATION  
  Follow   the   steps   outlined   below   to   provide   your   own   Window   Class   Name.    
   
   
   
  Open   your   project   work   space   containing   the   dialog   box   and   click   ResourceView.  
   
   
  Open   the   dialog   box   in   Resource   Editor.   Right-click   the   dialog   box   and   select   Properties.   Notice   an   entry   for   Class   Name   at   the   bottom   right.   This   edit   box   appears   disabled   if   you   are   using   a   resource   file   with   Microsoft   Foundation   Class   Library   support.   To   enable   this   option,   switch   to   the   top-level   node   on   the   resource   view,   then   right-click   and   select   Properties.   Clear   the   Enable   MFC   Features   check   box.   Now   display   the   properties   for   your   dialog   box.   The   Class   Name   edit   box   should   be   enabled.   Type   the   class   name;   for   instance   MyPrivateClassName  
   
   
  Alternatively,   open   the   .rc   file   as   a   text   file.   Go   to   the   desired   DIALOG   resource   and   add   the   CLASS   option.    
   
   
   
  IDD_LIMITDLGINSTANCE_DIALOG   DIALOGEX   0,   0,   195,   44  
  STYLE   DS_MODALFRAME   |   WS_POPUP   |   WS_VISIBLE   |   WS_CAPTION   |   WS_SYSMENU  
  EXSTYLE   WS_EX_APPWINDOW  
  CAPTION   "LimitDlgInstance"  
  CLASS   "MyPrivateClassName"   //   Add   your   class   name   here!  
  FONT   8,   "MS   Sans   Serif"  
  BEGIN  
          DEFPUSHBUTTON       "OK",IDOK,138,7,50,14  
          PUSHBUTTON             "Cancel",IDCANCEL,138,23,50,14  
          PUSHBUTTON             "&Test!",IDC_BUTTON1,48,14,49,15  
  END    
   
   
   
  Add   the   following   code   in   the   InitInstance()   function   of   the   CWinApp-derived   class.    
   
   
   
  BOOL   CLimitDlgInstanceApp::InitInstance()  
  {  
  /////////////////////////////////////////////////////////////////////////    
  /////////////////////////////////////////////////////////////////////////    
  WNDCLASS   wc;  
   
  //   Get   the   info   for   this   class.  
                    //   #32770   is   the   default   class   name   for   dialogs   boxes.  
  ::GetClassInfo(AfxGetInstanceHandle(),   "#32770",   &wc);  
   
  //   Change   the   name   of   the   class.  
  wc.lpszClassName   =   "MyPrivateClassName";  
   
  //   Register   this   class   so   that   MFC   can   use   it.  
  AfxRegisterClass(&wc);  
  /////////////////////////////////////////////////////////////////////////    
  /////////////////////////////////////////////////////////////////////////    
   
  //   ...  
  }    
   
   
   
  In   the   step   above,   in   the   call   to   ::GetClassInfo(),   make   sure   to   use   the   correct   HINSTANCE   call   if   your   dialog   resource   is   located   in   a   separate   DLL.  
   
   
  Build   and   run   your   application.   Use   the   Spy++   tool   to   verify   that   the   dialog   now   uses   the   new   class   name.