C / C++ / MFC

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

<br />
CRecordset* CDB::Query(CString path, CString SQLstring)<br />
{<br />
...some declarations... <br />
<br />
TRY <br />
{<br />
...i open database and then:<br />
<br />
CRecordset* recset = new CRecordset(&db);<br />
recset.Open(CRecordset::forwardOnly, SQLstring, CRecordset::readOnly);<br />
return recset; <br />
db.Close();<br />
}<br />
CATCH(CDBException, dbex)<br />
 {<br />
  AfxMessageBox("Error: " + dbex->m_strError);<br />
 }<br />
 END_CATCH;<br />
}<br />

<br />
CDB d;<br />
CRecordset *recset = d.Query(path,sqlstring);<br />

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

<br />
CRecordset* CDB::Query(CString path, CString SQLstring)<br />
{<br />
CDatabase db;<br />
CString driver,dsn;<br />
		<br />
driver = GetDriver(); //another function from this class<br />
<br />
dsn.Format("ODBC;DRIVER={%s};DSN='';DBQ=%s", driver, path);<br />
<br />
TRY <br />
{<br />
db.Open(NULL, false, false, dsn);<br />
CRecordset* recset = new CRecordset(&db);<br />
recset->Open(CRecordset::forwardOnly, SQLstring, CRecordset::readOnly);<br />
return recset; <br />
//db.Close();  was here but isn;t any more according to your suggestion <br />
}<br />
CATCH(CDBException, dbex)<br />
{<br />
AfxMessageBox("Error: " + dbex->m_strError);<br />
}<br />
END_CATCH;<br />
}<br />

<br />
void CBaseWindow::OnClickedButton1()<br />
{<br />
... // code which gives me path and sqlstring, it's ok for sure<br />
CString val;<br />
CDB d;<br />
CRecordset *recset = d.Query(path,sqlstring);<br />
<br />
// everything below is undoable because of "debug assertion failed" error. what i figured out is that recset is not opened :/... but opening it requires stuff like sql string so it makes no sense :/<br />
<br />
short fields = recset->GetODBCFieldCount();<br />
while(!recset.IsEOF())<br />
{<br />
   for(short i=0;i<fields;i++)<br />
   {<br />
      recset->GetFieldValue(i,val);<br />
      // i do something with val... <br />
   }<br />
   recset->MoveNext();<br />
}<br />
}<br />

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

typedef BOOL (CALLBACK* COMPLETION_CB_PTR)(int percentDone, void * pCBData);

void CMyObject::Foo()
{
  // call a function in the DLL that stores the address of the callback, and the callback data.
  // the callback data here is just the address of 'this' (the current object)
  DLLCallbackSetupFunction(cbFunction, this);
}
 
// this is what the DLL will call
BOOL CALLBACK cbFunction(int pctDone, void *pCBData)
{
    // cast that cbData pointer back to an object of type CMyObject,
    // and then we can use that object without trouble.
    CMyObject * pObj = (CMyObject*)pCBData;
    pObj->Bar(pctDone);
}
 
// and then cbFunction calls this:
void CMyObject::Bar(int iPctDone)
{
... whatever
}

// in the DLL
...
void *g_pCBData;
COMPLETION_CB_PTR g_pCB;
...
DLLCallbackSetupFunction(COMPLETION_CB_PTR pCB, void *pCBData)
{
  g_pCB = pCB;
  g_pCBData = pCBData;
}
 
then, something calls the callback
if (g_pCB)
{ 
  (g_pCB)(iPctDone, g_pCBData);
}