BUG: ListView Control's Left and Top Properties Return Unexpected Values (240944)


The information in this article applies to:

  • Microsoft Visual Basic Learning Edition for Windows 6.0
  • Microsoft Visual Basic Professional Edition for Windows 6.0
  • Microsoft Visual Basic Enterprise Edition for Windows 6.0
This article was previously published under Q240944

SYMPTOMS

When the Left or Top property of the ListView control is assigned a negative value, the result is a value greater by 1 pixel. Positive values return the expected result.

RESOLUTION

Step-by-Step Workaround

  1. Start a new Standard EXE project in Visual Basic. Form1 is created by default.
  2. On the Project menu, click to select Components, check Microsoft Windows Common Controls 6.0, and then click OK.
  3. Draw a ListView control on Form1. On the Properties window, set View = 0 - lvwSmallIcon.
  4. Add the following code to the General Declarations section of Form1:
    Option Explicit

Dim itm As ListItem

Private Sub Form_Click()
    Dim sngLeft As Single
    Dim sngTop As Single
    
    Me.ScaleMode = vbPixels
    sngLeft = -2
    sngTop = -2
    Set itm = ListView1.ListItems.Add(Text:="item")

    ' Inaccurate
    itm.Left = sngLeft
    itm.Top = sngTop
    MsgBox "Left = " & itm.Left & " Top = " & itm.Top

    ' More accurate
    LocateListItems itm, sngLeft, sngTop
    MsgBox "Left = " & itm.Left & " Top = " & itm.Top
End Sub

Private Sub LocateListItems(item As ListItem, x As Single, y As Single)
    Select Case x
        Case Is < -1.5
            x = x - 1
        Case Is < 0
            x = x - 1.1
        Case Else
    End Select
    item.Left = x
    Debug.Print "Item.Left = "; item.Left    
    
    Select Case y
        Case Is < -1.5
            y = y - 1
        Case Is < 0
            y = y - 1.1
        Case Else
    End Select
    item.Top = y
    Debug.Print "Item.Top = "; item.Top    
End Sub
  5. Run the project by pressing the F5 key, and note the results in the Immediate window. Without correction, the inaccurate result is displayed. After a call to the correcting function, the more accurate result is displayed.

STATUS

Microsoft has confirmed that this is a bug in the Microsoft products that are listed at the beginning of this article.

MORE INFORMATION

Because these properties are for positions that are stored as real numbers, they are usually not whole numbers. However, for any negative value that is assigned, the result is always 1 pixel greater than the assigned value.

Steps to Reproduce Behavior

  1. Start a new Standard EXE project in Visual Basic. Form1 is created by default.
  2. On the Project menu, click to select Components, check Microsoft Windows Common Controls 6.0, and then click OK.
  3. Draw a ListView control on Form1. On the Properties window, set View = lvwSmallIcon.
  4. Add the following code to the General Declarations section of Form1:
    Private Sub Form_Click()
    ListView1.ListItems(1).Left = -5
    Debug.Print "Left = "; ListView1.ListItems(1).Left
    ListView1.ListItems(1).Top = -5
    Debug.Print "Top = "; ListView1.ListItems(1).Top
End Sub

Private Sub Form_Load()
   Me.ScaleMode = vbPixels
   Call ListView1.ListItems.Add(Text:="item")
End Sub
  5. Run the project by pressing F5, click on the form, and note that this produces the following output in the Immediate window: Left = -3.968504
    Top = -3.968504

  6. Note that the result is 1 pixel greater than the assigned value.
Modification Type:MajorLast Reviewed:5/12/2003
Keywords:kbBug kbCmnCtrls kbCtrl kbListView kbpending kbSample KB240944
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