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Q137027: BUG: ScrollBars Don’t Display on DBList Control

Article: Q137027
Product(s): Microsoft Visual Basic for Windows
Version(s): 4.00
Operating System(s): 
Keyword(s): kbbuglist
Last Modified: 11-JAN-2001

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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 
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SYMPTOMS
========

Symptom 1
---------

When binding a DBList control to a Data control whose RecordSource property is
set to a Select statement with a Where clause, the ScrollBars do not display on
the DBList control. This is true even if the number of rows returned by the
Select statement exceeds the list size of the control (the number of items
DBList can display without scrolling).

Symptom 2
---------

Also, if the height of the DBList control is set to display only one item at a
time, the ScrollBars do not display on the DBList control.

CAUSE
=====

The DBList ScrollBar relies on the RecordCount property of the RecordSet. When
using Select with a Where clause in the RecordSource property,
RecordSet.RecordCount returns a value of 1. Usually this count is less than the
maximum number of items DBList can display without scrolling, so ScrollBars are
not displayed.

WORKAROUND
==========

Listed below are different ways to work around this problem depending on the
symptoms occurring:

Symptom 1
---------

- Issue a Recordset.MoveLast before showing the DBList control. For example, if
  Data1 is the Data control to which DBList is bound, place the following code
  in the Form_Load event procedure to solve the problem:

     Data1.Refresh
     Data1.RecordSet.MoveLast

-or-

- Issue a MoveNext enough times so that the RecordCount will return something
  greater than the number of items that can be visible in the DBList without
  scrolling. For example, if DBList can display 10 items at one time, place the
  following code in the Form_Load event procedure, assuming Data1 is the name
  of the Data Control:

     Data1.Refresh
     For x% = 0 To 10
        Data1.RecordSet.MoveNext
     Next x%

Symptom 2
---------

- Add the following code in the Activate event of the form that contains the
  DBList control:

     DBList1.SetFocus
     SendKeys "{Down}{Up}"

STATUS
======

Microsoft has confirmed this to be a problem in the DBList control included with
the products listed above. We are researching this problem and will post new
information here in the Microsoft Knowledge Base as it becomes available.

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

Steps to Reproduce Problem
--------------------------

Symptom 1
---------

1. Start a new project in Visual Basic 4.0. Form1 is created by default.

2. Add two DBList controls (DBList1 and DBList2) to Form1.

3. Add two Data Controls (Data1 and Data2) to Form1.

4. From the Properties window, set the properties for each control as follows:

  Data1:

        DatabaseName = Biblio.mdb
        RecordSource = Authors
        RecordsetType = 1 - Dynaset

  Data2:

        DatabaseName = Biblio.mdb
        RecordSource = Select Author From Authors where Au_Id > 0
        RecordsetType = 1 - Dynaset

  DBList1:

        RowSource = Data1
        ListField = Author

  DBList2:

        RowSource = Data2
        ListField = Author

5. Press the F5 key to run the application. DBList1 will have a ScrollBar, and
  DBList2 will not.

Symptom 2
---------

1. Start a new project in Visual Basic 4.0. Form1 is created by default.

2. Add a Data control and a DBListbox on the form.

3. Set the Data controls Databasename property to "Biblio.mdb"

4. Set the Data controls Recordsource property to "Publishers"

5. Set the DBList controls RowSource property to Data1.

6. Set the DBList controls BoundColumn property to PubID.

7. Set the DBList controls ListField property to Name.

8. Set the height of the DBList control to show only one item at a time.

9. Press the F5 key to run the application.

Additional query words: 4.00 buglist4.00 vb4win vb4all

======================================================================
Keywords          :  kbbuglist
Technology        : kbVBSearch kbAudDeveloper kbVB400Search kbVB400 kbVB16bitSearch
Version           : 4.00
Issue type        : kbbug

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

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