FIX: Double-Clicking ListBox Control Causes Invalid Page Fault (257686)



The information in this article applies to:

  • Microsoft Visual Basic Learning Edition for Windows 6.0, when used with:
    • the operating system: Microsoft Windows 95
    • the operating system: Microsoft Windows 98
    • the operating system: Microsoft Windows Millennium Edition
  • Microsoft Visual Basic Professional Edition for Windows 6.0, when used with:
    • the operating system: Microsoft Windows 95
    • the operating system: Microsoft Windows 98
    • the operating system: Microsoft Windows Millennium Edition
  • Microsoft Visual Basic Enterprise Edition for Windows 6.0, when used with:
    • the operating system: Microsoft Windows 95
    • the operating system: Microsoft Windows 98
    • the operating system: Microsoft Windows Millennium Edition

This article was previously published under Q257686

SYMPTOMS

In a case where you have a form with a ListBox control and you are populating the list from a database, if you unload the form in the double-click event of the ListBox control, an Invalid Page Fault occurs.

STATUS

Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article. This bug was corrected in the latest service pack for Visual Studio 6.0.

For additional information about Visual Studio service packs, click the following article numbers to view the articles in the Microsoft Knowledge Base:

194022 INFO: Visual Studio 6.0 Service Packs, What, Where, Why

194295 HOWTO: Tell That a Visual Studio Service Pack Is Installed

To download the latest Visual Studio service pack, visit the following Microsoft Web site:

MORE INFORMATION

The following steps use the Biblio database. They assume that the database is located in the default Visual Basic installation path:

C:\Program Files\Microsoft Visual Studio\Vb98\Biblio.mdb

Steps to Reproduce Behavior

  1. Start a new Standard EXE project in Visual Basic. Form1 is created by default.
  2. On the Project menu, select References. On the References dialog box, check Microsoft ADO 3.51 Object Library, and then click OK.
  3. On the Project menu, add a new module, and then insert the following code:
    Option Explicit
    
    Public MainDatadb As Database
    					
  4. Add a Command Button to Form1.
  5. Add the following code to the code window of Form1:
    Option Explicit
    
    Private Sub Command1_Click()
        Form2.ShowMeGeneral MainDatadb, "Authors", "Author", "AU_id", , _
          "Find an author", "au_id"
    End Sub
    
    Private Sub Form_Load()
        Dim DBName As String
    
        ' Change the following path if necessary for your system
        DBName = "C:\Program Files\Microsoft Visual Studio\VB98\BIBLIO.MDB"
        Set MainDatadb = OpenDatabase(DBName, False, False)
    End Sub
    					
  6. On the Project menu, add a second form, Form2, to the project.
  7. Add a ListBox control to Form2.
  8. Add the following code to the code window of Form2:
    Option Explicit
    
    Public SelectedValue As String
    Public KeyValue As String
    Public Canceled As Boolean
    
    Public Sub ShowMeGeneral(DBName As Database, DBTable As String, _
     FldDisplay As String, FldReturn As String, Optional InSql As Variant, _
     Optional Title As Variant, Optional KeyField As Variant)
    
        Dim Sql As String, TempRS As Recordset
        Dim Indx As Integer, TmpString As String
        Dim DisplayString As String
        If IsMissing(InSql) Then
            Sql = "SELECT [" & FldDisplay & "],[" & FldReturn & "] " & _
            "FROM " & DBTable & " ORDER BY [" & FldDisplay & "];"
        Else
            Sql = InSql
        End If
        Set TempRS = DBName.OpenRecordset(Sql, , dbReadOnly)
        Do Until Indx > 5000
            DisplayString = TempRS(FldDisplay) & ""
            DisplayString = "abcdefghijklmm" & Indx
            List1.AddItem DisplayString
            Indx = Indx + 1
            TempRS.MoveNext
        Loop
        TempRS.Close
        Set TempRS = Nothing
        List1.ListIndex = 0
        Canceled = True
        Me.Show vbModal
    End Sub
    
    Private Sub List1_DblClick()
        Unload Me
    End Sub
    					
  9. Run the project and click on Command1 to open Form2.
  10. Double-click on an item in the ListBox control on Form2. The result should be an Invalid Page Fault.

Modification Type:MinorLast Reviewed:12/12/2005
Keywords:kbBug kbCtrl kbfix kbListBox kbVS600sp4fix kbVS600sp5fix KB257686