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Using huge CString and CEdit: limit 64K ?

Posted on 2002-03-31
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Last Modified: 2013-11-20
Hi there !

I have a small dlg-based app that connects to an internet server, gets some txt-output from there and displays it in a CEdit control. By clicking a button, i use this code fragment to receive and display the data (i got this code from some experts-exchange post):

----------
HCURSOR hCursOld = SetCursor(LoadCursor(NULL, IDC_WAIT));
m_cStartButton.EnableWindow(FALSE);

CInternetSession* pInternetSession;
pInternetSession = new CInternetSession();
     
m_sDataEdit.Empty();  // this is a CString, attached to a CEdit control of my dlg

CHttpFile* pFile = (CHttpFile*)pInternetSession->OpenURL("http://www.somewhere.com/returntxt.php",1,INTERNET_FLAG_TRANSFER_BINARY | INTERNET_FLAG_DONT_CACHE | INTERNET_FLAG_RELOAD,NULL,0);

if ( pFile )
{
 char buf[256];
 while( int iRead = pFile->Read( buf, 255 ) )
 {
   buf[iRead] = '\0';
   m_sDataEdit += CString(buf);
 }
         
 pFile->Close();
 delete pFile;
}

pInternetSession->Close();
delete pInternetSession;

m_cStartButton.EnableWindow(TRUE);
UpdateData(FALSE);

SetCursor(hCursOld);
----------

This totally works with W2K, and I receive some huge data (ab 70k) and show it. But, with W98, the program crashes or just shows nothing.
As far as I checked, the data is received, but as I extend 64k of data (chars), the CString ("m_sDataEdit") has some "overrun" or whatever and gets lost.

Can u help me ?
Why is there a difference between W2K and W98 on this issue ? I understand that CEdit control has some memory limit (4k ? 32k?), anyway. Do i need a totally different approach for showing "huge" text within a dialog app ?

THX a lot
0
Comment
Question by:MiKo93
3 Comments
 
LVL 23

Expert Comment

by:Roshan Davis
ID: 6909703
Try this link...

http://codeproject.com/editctrl/crysedit.asp

this may help u...

GOOD LUCK
0
 
LVL 49

Accepted Solution

by:
DanRollins earned 200 total points
ID: 6910918
The EDIT control managed by the CEdit class is not able to handle or display text greater than 64K.

There are two basic choices:
1) truncate the text.
2) Use CRichEdit class rather than CEdit.

If you use #2, then be sure to execute this fn sometime before you open the dialog box:

   AfxInitRichEdit();

In a dilaog-based app, this is commonly placed into the CMyApp.InitInstance() fn, just before that call to dlg.DoModal().

Do you need help in changing your existing CEdit control into a CRichEdit control?

-- Dan
0
 

Author Comment

by:MiKo93
ID: 6912818
Thank you both for your comments.

Dan, I used #2 and rebuilt with a CRichEdit, and it worked ! Therefore, I'll accept your comment as answer.

Yours, MiKo
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