MFC does not currently provide methods for extracting
container and document information from DAO collections. The sample, CONDOC.EXE
demonstrates how to implement this extraction using MFC DAO objects and, in
particular, demonstrates using DAO OLE interfaces not directly available from
the MFC DAO classes.
Containers provide an application-independent
way for an application to store objects in a database. For example, Microsoft
Access uses separate containers to store forms, reports, macros, and modules.
This is in a format native only to Access. However, the code below shows how to
see which containers are stored in an Access database.
Documents are
used to store a specific instance of an application-specific object within a
container, such as a form, a report, etc. A container can have more than one
document collection. To repeat, Microsoft Access documents and containers are
in a format native to Access and not available programatically from other
products except through OLE Automation using Access
itself.
The
following files are available for download from the Microsoft Download
Center:
Condoc.exe
(http://download.microsoft.com/download/vc40std/sample/4/win98/en-us/condoc.exe)
For
additional information about how to download Microsoft Support files, click the
following article number to view the article in the Microsoft Knowledge Base:
119591
(http://support.microsoft.com/kb/119591/EN-US/
)
How to Obtain Microsoft Support Files from Online Services
Microsoft scanned this file for viruses. Microsoft used the most
current virus-detection software that was available on the date that the file
was posted. The file is stored on security-enhanced servers that help to
prevent any unauthorized changes to the file.
NOTE: Use the -d option when running CONDOC.EXE to decompress the file
and recreate the proper directory structure.
Sample Code
The following code demonstrates how to extract Container and
Document information and store it in a Tree View control:
// Command handler which performs the pertinent operations
/////////////////////////////////////////////////////////////////////
//
void CCONDOCView::OnGetinfoOpenMDB()
{
// Prepare the open file dialog
static char BASED_CODE szFilter[] = _
T( "Access Database Files (*.mdb) | *.mdb" );
CFileDialog dlg(TRUE, "mdb", NULL,
OFN_HIDEREADONLY| OFN_OVERWRITEPROMPT, szFilter);
// To be retrieved by the open file dialog
CString strFile;
// open file dialog
if(dlg.DoModal() == IDOK)
{
strFile = dlg.m_ofn.lpstrFile;
if(strFile.Right(3).CompareNoCase("mdb") // verify extension
{
AfxMessageBox("File Extension error");
return;
}
}
// you will display the info in a tree control
CTreeCtrl &tree = GetTreeCtrl();
// the root of all items!
HTREEITEM itemDatabase = tree.InsertItem(
dlg.m_ofn.lpstrFile );
// An MFC DAO object
CDaoDatabase db;
// straight DAO interface pointer variables
ConDoctainers *pContainers=NULL;
ConDoctainer* pCon=NULL;
DAODocuments* pDocuments=NULL;
DAODocument* pDoc=NULL;
// To be used for iterating through the collections
short count;
short doccount;
// open the .MDB
try
{
db.Open( strFile );
}
catch( CDaoException* e )
{
AfxMessageBox( e->m_pErrorInfo->m_strDescription );
return;
}
// Using the DAODatabase interface pointer method contained
// by the MFC/DAO class CDaoDatabase, you retrieve the interface's
// set of collections.
if( FAILED( db.m_pDAODatabase->get_Containers( &pContainers ) ) )
{
AfxMessageBox( "Collection not found" );
db.Close();
return;
}
// Once you have the set of collections, you iterate thru each
// individual collection, display some of its attributes,
// then get the document collection on the container,
// and iterate thru the individual documents, displaying some
// of the attributes of the documents.
// See the dbdao.h in the DAOSDK\INCLUDE for more information
try
{
// get the count property of the containers collection
pContainers->get_Count( &count );
HTREEITEM itemContainers = tree.InsertItem( _T( "Containers" )
, itemDatabase );
// iterate thru the containers
while( --count > 0 )
{
// get an individual container and iterate thru its
//attributes
pContainers->get_Item( COleVariant( count, VT_I2 ),
&pCon );
BSTR bstr=NULL;
pCon->get_Name( &bstr );
CString strName( ( LPCTSTR ) bstr );
HTREEITEM itemName = tree.InsertItem( strName,
itemContainers );
pCon->get_Owner( &bstr );
CString strOwner(_T("Owner: ") );
strOwner += (LPCTSTR) bstr;
HTREEITEM itemOwner = tree.InsertItem( strOwner,
itemName );
pCon->get_UserName( &bstr );
CString strUserName(_T("User Name: ") );
strUserName += (LPCTSTR) bstr;
HTREEITEM itemUserName = tree.InsertItem( strUserName,
itemName );
// Now get the documents collection
if( FAILED ( pCon->get_Documents( &pDocuments ) ) )
{
AfxMessageBox( "Collection not found" );
db.Close();
return;
}
// Now get the number of documents contained in the
// container
pDocuments->get_Count( &doccount );
HTREEITEM itemDocuments = tree.InsertItem(
_T( "Documents"), itemName );
// iterate thru the documents
while( --doccount > 0 )
{
// get an individual document and iterate thru
// some of its attributes.
pDocuments->get_Item( COleVariant( doccount, VT_I2 ),
&pDoc );
pDoc->get_Name( &bstr );
CString strDocName( ( LPCTSTR ) bstr );
HTREEITEM itemDocName = tree.InsertItem( strDocName,
itemDocuments );
pDoc->get_Owner( &bstr );
CString strDocOwner(_T("Owner: ") );
strDocOwner += (LPCTSTR) bstr;
tree.InsertItem( strDocOwner, itemDocName );
pCon->get_UserName( &bstr );
CString strDocUserName(_T("User Name: ") );
strDocUserName += (LPCTSTR) bstr;
tree.InsertItem( strDocUserName, itemDocName );
}
}
}
catch( CDaoException* e)
{
AfxMessageBox( e->m_pErrorInfo->m_strDescription );
db.Close();
return;
}
db.Close();
}
/////////////////////////////////////////////////////////////////////
// END OF SAMPLE CODE
Microsoft Jet Database Engine Programmer's Guide, ISBN #:
1-55615-877-7.
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