Solved

Saving List Items to Disk

Posted on 2003-11-04
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Last Modified: 2013-11-20
I have the following code in my project:

void CIRCServerConnector::SaveServerList(void)
{
      CFile fileServLst("servlist.dat", CFile::modeCreate | CFile::modeReadWrite);

      CArchive arStore(&fileServLst, CArchive::store);

      POSITION aPos = m_listServers.GetHeadPosition();
      CIRCServer* temp;

      while(aPos)
      {
            temp = m_listServers.GetNext(aPos);
            arStore.WriteObject(temp);
      }
      arStore.Close();
}

It is supposed to go through a CTypedPtrList and save each item to disk..one by one. Right now...I am getting a dialog box that pops up and says "An unsupported operation was attempted"...never seen that before. Can anyone help tell me what is going on here?
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Question by:SGyves
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8 Comments
 
LVL 23

Expert Comment

by:Roshan Davis
ID: 9684129
Attempting to retrieve a CIRCServer* on any other object will result in a system error (the utterly enigmatic "An unsupported operation was attempted"), MSDN documented something like this.

can u tell me, in which point of code that error comes..?

Rosh :)
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LVL 9

Accepted Solution

by:
Priyesh earned 400 total points
ID: 9684172
Just a reminder list, you might be already doing this.

class CIRCServer : public CObject//derive from cobject to
{
  DECLARE_SERIAL(CIRCServer)
public:
   void Serialize(CArchive& ar) ;
public:
   CString szName ;
};

IMPLEMENT_SERIAL(CIRCServer, CObject, 1)//needed to enable serialization

void CIRCServer::Serialize(CArchive& ar)//Called by WriteObject
{
   if(ar.IsLoading())
     ar >> szName ;
   else
     ar << szName ;  
}

And, a try - catch to catch CArchiveException or others to get any further details abt the error
0
 

Author Comment

by:SGyves
ID: 9684336
Rosh...it happens right on the WriteObject line:

arStore.WriteObject(temp);


that one.
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Author Comment

by:SGyves
ID: 9684340
OMG...I think I forgot the IMPLEMENT_SERIAL and DECLARE_SERIAL statements.   (Slapping my head)

0
 

Author Comment

by:SGyves
ID: 9684342
A long day indeed...that was it.
0
 

Author Comment

by:SGyves
ID: 9684585
Hey...what is the best way to read these back from disk untill there are no more....meaning...how can I check for EOF??
0
 
LVL 9

Expert Comment

by:Priyesh
ID: 9684799
Would this work for you??

      CIRCServer clsServer ;
      clsServer.szName = "IRCServer" ;

      CTypedPtrArray<CObArray, CIRCServer*> clsArraySave, clsArrayLoad ;
      clsArraySave.Add(&clsServer) ;

//Write.
      {
            CFile clsFile("c:\\ircobjects.dat", CFile::modeCreate|CFile::modeWrite) ;
            CArchive ar(&clsFile, CArchive::store) ;
            clsArraySave.Serialize(ar) ;
      }


//Read
      {
            CFile clsFile("c:\\ircobjects.dat", CFile::modeRead) ;
            CArchive ar(&clsFile, CArchive::load) ;
            clsArrayLoad.Serialize(ar) ;

            CIRCServer* pServer = clsArrayLoad.GetAt(0) ;
            TRACE("Name = %s\n", pServer->szName) ;
      }

0
 

Author Comment

by:SGyves
ID: 9687910
Yes...I believe that will work. As I understand...the serialize for the CTypedPtrList serializes all elemnts into the file. Cool.
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