文档/视图结构中的各个部分是如何联系到一起的[13]

                     pframe->destroywindow();

                     return null;

              }

              m_nuntitledcount++;

       }

       else

       {

              // 打开一个已经存在的文件

              cwaitcursor wait;

              if (!pdocument->onopendocument(lpszpathname))

              {

                     // user has be alerted to what failed in onopendocument

                     trace0("cdocument::onopendocument returned false.\n");

                     pframe->destroywindow();

                     return null;

              }

              pdocument->setpathname(lpszpathname);

       }

       initialupdateframe(pframe, pdocument, bmakevisible);

       return pdocument;

}