BUG: ScrollBars Don't Display on DBList Control

• Standard, Professional, and Enterprise Editions of Microsoft Visual Basic, 16-bit and 32-bit, for Windows, version 4.0

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.