[API Windows] Combo box et CBN_SELCHANGE

LRESULT CALLBACK MainProc(HWND hWnd, UINT mes, WPARAM wParam, LPARAM lParam)
{

   switch (mes)
   {
   case WM_CREATE:
	hComboBox1=CreateWindow(
        TEXT("COMBOBOX"),
        TEXT(""),
        WS_CHILD|WS_VISIBLE|CBS_DISABLENOSCROLL|CBS_DROPDOWNLIST,
        20,40,
        180,150,
        fenetrePrincipale,
        (HMENU)ID_COMBOBOX_1,
        instance,
        NULL);
		return 0;
	case WM_INITDIALOG:
		SendMessage(hComboBox1,CB_ADDSTRING,0,(LONG)TEXT("Insérer une variable globale"));
		return 0;
   case WM_DESTROY:
      PostQuitMessage(0);
      return 0;
   default:
      return DefWindowProc(hWnd, mes, wParam, lParam);
   }
}