How To Calling DAO Directly from MFC to Change a User's Password

  COleVariant varOldName;
  COleVariant varNewName( _T("NewUser"), VT_BSTRT );

  // Code to assign pUser to a valid value omitted
  DAOUser *pUser = NULL;

  // These method declarations were taken from Dbdaoint.h
  // STDMETHOD(get_Name) (THIS_ BSTR FAR* pbstr) PURE;
  // STDMETHOD(put_Name) (THIS_ BSTR bstr) PURE;

  DAO_CHECK( pUser->get_Name ( &V_BSTR(&varOldName) ) );
  DAO_CHECK( pUser->put_Name ( V_BSTR (&varNewName) ) );
				

  COleVariant varName( _T( "MyName" ), VT_BSTRT );
  CString str = V_BSTRT( &varName );
				

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Sample Code

   // The following code presents several functions you can use to manage
   // MFC DAO classes in a way that allows you to call the DAO interfaces.
   // It then shows how to use those functions within InitInstance().

   // Set the system database that the DAO database engine will use:
   void AfxDaoSetSystemDB(CString & strSystemMDB)
   {
     COleVariant varSystemDB(strSystemMDB,VT_BSTRT );

     // Initialize DAO for MFC:
     AfxDaoInit();
     DAODBEngine* pDBEngine = AfxDaoGetEngine();

     ASSERT(pDBEngine != NULL);

     // Call put_SystemDB method to set the system database for DAO engine:
     DAO_CHECK( pDBEngine->put_SystemDB( varSystemDB.bstrVal ) );
   }

   void AfxDaoSetDefaultUser(CString & strUserName, CString & strPassword)
   {
     COleVariant varUserName( strUserName, VT_BSTRT );
     COleVariant varPassword( strPassword, VT_BSTRT );

     DAODBEngine* pDBEngine = AfxDaoGetEngine();
     ASSERT(pDBEngine != NULL);

     // Set default user:
     DAO_CHECK( pDBEngine->put_DefaultUser(varUserName.bstrVal));

     // Set default password:
     DAO_CHECK( pDBEngine->put_DefaultPassword(varPassword.bstrVal));
   }

   void AfxDaoChangePassword(CString & strUserName, CString &
   strOldPassword, CString & strNewPassword)
   {

       // Create(Open) Workspace:
       CDaoWorkspace   wsp;
       CString         strWspName     = _T("Temp Workspace");

       wsp.Create( strWspName, strUserName, strOldPassword );
       wsp.Append();

       // Determine how many objects there are in the Users collection:
       short       nUserCount;
       short       i;
       DAOUser     *pUser  = NULL;
       DAOUsers    *pUsers = NULL;

       // Side-effect is implicit OLE AddRef() on DAOUser object:
       DAO_CHECK( wsp.m_pDAOWorkspace->get_Users( &pUsers ) );

       // Side-effect is implicit OLE AddRef() on DAOUsers object:
       DAO_CHECK( pUsers->get_Count( &nUserCount ) );

   TRACE( "# of users in collection = %d\n", nUserCount );

       // Traverse through the list of users and change password for userid
       // used to create/open the workspace:
       for( i = 0; i < nUserCount; i++ )
       {
           COleVariant varIndex( i, VT_I2 );
           COleVariant varName;

           // Retrieve information for user i
           DAO_CHECK( pUsers->get_Item( varIndex, &pUser ) );

           // Retrieve name for user i
           DAO_CHECK( pUser->get_Name( &V_BSTR(&varName)) );

           TRACE( "User # %d Name = %s\n", i, V_BSTRT(&varName) );

           CString strTemp = V_BSTRT(&varName);

           // If there is a match, change the password:
           if( strTemp == strUserName )
           {
               COleVariant varOldPwd( strOldPassword, VT_BSTRT );
               COleVariant varNewPwd( strNewPassword, VT_BSTRT );

               DAO_CHECK( pUser->NewPassword( V_BSTR( &varOldPwd ),
                                              V_BSTR( &varNewPwd ) ) );

               TRACE( "\t Password is changed\n" );
           }
       }

       // Clean up: decrement the usage count on the OLE objects:
       pUser->Release();
       pUsers->Release();

       wsp.Close();
   }

   BOOL CMyApp::InitInstance()
   {
     // Specify path to the Microsoft Access system database:
     CString strSystemDB =
        _T("c:\\Program Files\\MSOffice\\access\\System.mdw");

     // Set system database before MFC initilizes DAO:
     AfxDaoSetSystemDB(strSystemDB);

     // User name and password manually added by using Microsoft Access:
     CString strUserName = _T("NewUser");
     CString strOldPassword = _T("Password");
     CString strNewPassword = _T("NewPassword");

     // Set default user so that MFC will be able to log in by default
     // using the user name and password from the system database:
     AfxDaoSetDefaultUser(strUserName,strOldPassword);

     // Change the password. You should be able to call this function from
     // anywhere in your MFC application:
     ChangePassword(strUserName,strOldPassword,strNewPassword);

   // Remainder of your InitInstance code:
   ...

   }