DOCUMENT:Q129286  11-JAN-2001  [vbwin]
TITLE   :PRB: Clone Won't Support All ListFields & ListIndexes Methods
PRODUCT :Microsoft Visual Basic for Windows
PROD/VER:4.00
OPER/SYS:
KEYWORDS:kbDatabase

======================================================================
-------------------------------------------------------------------------------
The information in this article applies to:

 - Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0 
 - Microsoft Visual Basic Professional Edition, 16-bit, for Windows, version 4.0 
 - Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 
 - Microsoft Visual Basic Enterprise Edition, 16-bit, for Windows, version 4.0 
 - Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 
-------------------------------------------------------------------------------

SYMPTOMS
========

The ListFields (Dynaset and Snapshot method) and ListIndexes (Table method) used
against a Clone created from a RecordSet object will generate the following
error with the Microsoft DAO 3.0 Object Library:

   Function marked as restricted or uses an OLE type not supported in Visual
   Basic

If you chose the Microsoft DAO 2.5/3.0 Compatibility Library and used DynaSet,
SnapShot or Table objects, the ListFields and ListIndexes method used against a
Clone created from a DynaSet, Snapshot, Table, or RecordSet object will generate
this error:

   Run-time error '3251'
   Feature not available

CAUSE
=====

When a Clone is created from any type of RecordSet object, the resulting Clone
is a RecordSet object -- not the Visual Basic version 3.0 DynaSet, SnapShot, or
Table types. It is not dependent on the type of the object from which it was
created. Because the Clone is a RecordSet, only RecordSet properties and methods
are available.

RESOLUTION
==========

Visual Basic Version 4.0
------------------------

The ListFields and ListIndexes methods are included in Visual Basic version 4.0
for compatibility with earlier versions of Visual Basic. For all RecordSet
objects, Microsoft recommends that you enumerate the Fields or Indexes
collection of the object containing the fields or indexes you want to list.

For Cloned objects, you may need to recode any use of the ListIndexes to
enumerate the Fields or Indexes collection of the object. For more information,
please see the "Examples of Converting Code to Jet Version 2.5" topic in the
Visual Basic version 4.0 Help menu.

Steps to Demonstrate the Correct Alternative to ListFields
----------------------------------------------------------

1. Start a new project in Visual Basic. Form1 is created by default.

2. Add a data control (Data1) to Form1.

3. Set the following properties for Data1.

   Property       Value
   -------------------------
   Databasename   Biblio.MDB
   RecordSource   Authors

4. Add the following code to the Form1_Click procedure:

      Sub Form1_Click ()
         Dim RS As RecordSet
         Set RS = Data1.Recordset.Clone()
         For Each Fld In RS.Fields
            Print Fld.Name
         Next
      End Sub

5. Start the program by choosing Start from the Run menu or by pressing the F5
   key.

STATUS
======

This behavior is by design.

MORE INFORMATION
================

Steps to Reproduce Behavior in Visual Basic
-------------------------------------------

1. Start a new project in Visual Basic. Form1 is created by default.

2. Add a data control (Data1) to Form1.

3. Set the following properties for Data1:

   Property       Value
   -------------------------
   Databasename   Biblio.MDB
   RecordSource   Authors

4. Add the following code to the Form1_Click procedure:

      Sub Form1_Click ()
         Dim DS As Dynaset, LF As Snapshot
         Set DS = Data1.Recordset.Clone()
         Set LF = DS.Listfields()
         While Not LF.EOF()
            Print LF("name")
            LF.Movenext
         Wend
      End Sub

5. Start the program by choosing Start from the Run menu or by pressing the F5
   key.

Depending on which DAO Reference you chose under Tools References, you will get
one of the two errors mentioned above.

Additional query words: 4.00 vb4win vb4all

======================================================================
Keywords          : kbDatabase 
Technology        : kbVBSearch kbAudDeveloper kbVB400Search kbVB400 kbVB16bitSearch
Version           : 4.00
Issue type        : kbprb

=============================================================================

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