Re: A problem about CHtmlView::Navigate2

From:

=?Utf-8?B?VG9tIExlZQ==?= <Tom.Lee@community.nospam>

Newsgroups:

microsoft.public.vc.mfc

Date:

Thu, 9 Aug 2007 01:46:04 -0700

Message-ID:

<6C78930E-7A44-47A2-A162-0A2B1712E941@microsoft.com>

Hi AliR,

Thanks for your great suggestion. It resovled this issue:)
But I don't think we should use "Yeild" in the OnTimer function, because the
message loop will get the timer message again and again, finally the app may
crash because of stack overflow.
In this case, we could return directly, it works fine now!
void CTestHVView::OnTimer(UINT nIdEvent)
{
    if (READYSTATE_COMPLETE != GetReadyState())
    {
        return;
    }
...
}
Thanks for your help!
--
Tom Lee

"AliR (VC++ MVP)" wrote:

I think you should wait for the first Navigate2 to compete before you issue
the next one. Earlier I read that you don't want to use OnNavigateComplete2.

Here is an alternative:

    //navigate to url
   m_pHTMLView->Navigate2(Filename);

    //don't let the function go any further until the page load is done
   while (m_pHTMLView->GetReadyState() != READYSTATE_COMPLETE)
   {
      ((CMyApp *)AfxGetApp())->Yeild();
   }

    //the loading is done, do something with the page. (In my case I called
m_pHTMLView->OnFilePrint)

void CMyApp::Yeild()
{
MSG Msg;

   while (PeekMessage(&Msg,NULL,0,0,PM_REMOVE))
   {
      if (!PreTranslateMessage(&Msg))
      {
         TranslateMessage(&Msg);
         DispatchMessage(&Msg);
      }
   }
}

AliR.

"Tom Lee" <Tom.Lee@community.nospam> wrote in message
news:BC70C71D-74E5-4133-850A-E2E1FC0EB120@microsoft.com...

I found if I call the CHtmlView::Navigate2 very quickly, it will hang the
process.

I made a tiny MDI application to verify this problem. The CTestHVViewis
derived from CHtmlView.
In the application, I created a timer on CTestHVView::OnInitialUpdate, and
call Navigate2 to a xml file in the OnTimer function.

The application will will hang. From the call stack, it is hanged in
msxml3.dll.

Here is some codes for reference:
class CTestHVView : public CHtmlView
{
...
protected:
vector<CString> m_vctFullPath;
vector<CString>::iterator m_curIter;
...
};

void CTestHVView::OnInitialUpdate()
{
CHtmlView::OnInitialUpdate();

//Get the XML files full path and put them into a vector.
TCHAR szPath[MAX_PATH*4];
ZeroMemory(szPath, MAX_PATH*4);
GetCurrentDirectory(MAX_PATH*4, szPath);
CString csDir(szPath);
csDir += _T("\\XML\\");
CString csTmp(csDir+_T("*.xml"));

WIN32_FIND_DATA FindFileData;
HANDLE hFind;
hFind = FindFirstFile(csTmp, &FindFileData);
if (INVALID_HANDLE_VALUE == hFind)
{
return;
}

OutputDebugString(_T("++++++++Use the following XML to test+++++++\n"));
do{
m_vctFullPath.push_back(csDir+FindFileData.cFileName);
OutputDebugString(csDir+FindFileData.cFileName+_T("\n"));
}while(FindNextFile(hFind, &FindFileData));
FindClose(hFind);
OutputDebugString(_T("++++++++Use the above XML to test+++++++\n"));

m_curIter = m_vctFullPath.begin();
this->SetTimer(1, 10, NULL);
}

void CTestHVView::OnTimer(UINT nIdEvent)
{
static int nMax = 1000;
static int i = 0;
if (++i > nMax)
{
KillTimer(1);
i = 0;
return;
}
if (0 == m_vctFullPath.size())
{
KillTimer(1);
i = 0;
return;
}
if (m_curIter == m_vctFullPath.end())
{
m_curIter = m_vctFullPath.begin();
}
this->Navigate2(*m_curIter, NULL, NULL);
CString cs;
cs.Format(_T("i = %d, Navigate2 %s\n"), i, *m_curIter);
OutputDebugString(cs);
m_curIter++;
}

//Use this function to tigger the nvaigate2 again.
void CTestHVView::OnRunAgain()
{
SetTimer(1, 10, NULL);
}

Any comments are very appreciated!
Thanks,

--
Tom Lee