ACC97: Listview Control Loses Data When Changing Properties

ID: Q166912

The information in this article applies to:

Microsoft Access 97

SYMPTOMS

Moderate: Requires basic macro, coding, and interoperability skills.

When you toggle the Visible or Enabled properties of a ListView control, the control loses its records by approximately one-half each time that those properties are cycled.

NOTE: This occurs with Microsoft ListView Control, version 5.0, which is available with Microsoft Office 97 Developer Edition Tools.

RESOLUTION

Each time you toggle the Enabled or Visible properties of the ListView control, clear the ListView control and rerun code to fill the control with data. You can use the Clear method of the ListItems collection in the control to remove all the items. The following example uses a command button to toggle the Visible property of a ListView control without losing rows of data:

1. Follow steps 1 through 7 in the "Steps to Reproduce Problem" section

   later in this article.

2. Add a command button to the form. Set its Name property to Command0, and

   set its OnClick property to the following event procedure:

      Private Sub Command0_Click
         Dim db As Database, rs As Recordset
         Dim itmX As ListItem
         Set db = CurrentDb()
         Set rs = db.OpenRecordset("Employees", dbOpenDynaset)

         ' Toggle the Visible property of the control.
         Me!ListView1.Visible = Not Me!ListView1.Visible

         ' Clear and then refill the control with data.
         While Not rs.EOF
            Set itmX = ListView1.ListItems.Add(, , CStr(rs![FirstName] ))
            If Not IsNull(rs![LastName]) Then
               itmX.SubItems(1) = CStr(rs![LastName])
            End If
            If Not IsNull(rs![BirthDate]) Then
               itmX.SubItems(2) = rs![BirthDate]
            End If
            rs.MoveNext
         Wend
      End Sub

3. Save the form as frmListView, and then switch it to Form view. Note that

   as you click the command button to toggle the Visible property of the
   ListView control, the number of records displayed in the control remains
   the same.

STATUS

Microsoft has confirmed this to be a problem in Microsoft Office 97 Developer Edition Tools.

MORE INFORMATION

The Microsoft ListView Control, version 5.0, is one of the controls included in the ActiveX control file, Comctl32.ocx. This behavior exists in version 5.00.3601 of Comctl32.ocx.

Steps to Reproduce Problem

1. Start Microsoft Access and open the sample database Northwind.mdb.

2. Create a new form not based on any table or query in Design view.

3. On the Insert menu, click ActiveX Control.

4. In the Insert ActiveX Control dialog box, select Microsoft ListView

   Control, version 5.0, and then click OK.

5. Set the following properties of the ListView control:

      Name: ListView1
      Width: 4"
      Height: 2"

6. On the View menu, click Code.

7. Type the following procedure, which populates the ListView control with

   data when you open the form:

      Private Sub Form_Open(Cancel As Integer)
         Dim db As Database, rs As Recordset
         Dim itmX As ListItem
         Set db = CurrentDb()
         Set rs = db.OpenRecordset("Employees", dbOpenDynaset)

         ListView1.ColumnHeaders.Add, , "First Name", ListView1.Width/3
         ListView1.ColumnHeaders.Add, , "Last Name", _
            ListView1.Width/3, lvwColumnCenter
         ListView1.ColumnHeaders.Add, , "Birthdate", _
            ListView1.Width/3
         ListView1.View = lvwReport

         While Not rs.EOF
            Set itmX = ListView1.ListItems.Add(, , CStr(rs![FirstName] ))
            If Not IsNull(rs![LastName]) Then
               itmX.SubItems(1) = CStr(rs![LastName])
            End If
            If Not IsNull(rs![BirthDate]) Then
               itmX.SubItems(2) = rs![BirthDate]
            End If
            rs.MoveNext
         Wend
      End Sub

8. Add a command button named Command0 to the form, and set its OnClick

   property to the following event procedure:

      Private Sub Command0_Click()
         Me!ListView1.Enabled = Not Me!ListView1.Enabled
      End Sub

9. Save the form as frmListView, and then switch it to Form view. Note that

   as you click the command button to toggle the Enabled property of the
   ListView control, the number of records displayed in the control reduces
   by about half. However, after the number of records is reduced to one,
   the last record continues to display even if you continue to click the
   command button.

REFERENCES

For more information about the ListView control, search the Help Index for "ListView control."

Additional query words: disappear reduce diminish

Keywords          : kbinterop kbprg
Version           : 97
Platform          : WINDOWS
Hardware          : x86
Issue type        : kbbug

Last Reviewed: November 20, 1998