Listview / API

You will need a module with the following:

option Explicit

Declare Function GetTextExtentPoint32 Lib "gdi32" Alias "GetTextExtentPoint32A" _
(byval hdc as Long, byval lpsz as string, byval cbString as Long, _
lpSize as TextSize_t) as Long
'computes the width and height of the specified text

' the struct type where some text's dims are returned
public Type TextSize_t
cx as Long
cy as Long
End Type

Then a form module with these items:

option Explicit
option Base 1 ' line up with listview
' make two command buttons: cmdColWidths and cmdGetSizes
' make a ListView called: ListView1
' feel free to email me: [email protected]

private Sub cmdColWidths_Click()
' get the current column widths in pixels
Dim CurrentMode as Long
Dim i as Integer
Dim ColWidths() as Long
Dim str as string

CurrentMode = me.ScaleMode

str = ""
ReDim ColWidths(ListView1.ColumnHeaders.Count)

for i = 1 to ListView1.ColumnHeaders.Count
ColWidths(i) = ListView1.ColumnHeaders(i).Width
str = str & i & ": " & ListView1.ColumnHeaders(i).Width & vbCrLf
next i

me.ScaleMode = CurrentMode

MsgBox str ' display the widths

End Sub

private Sub cmdExit_Click()
Unload me

End Sub

private Sub cmdGetSizes_Click()
Dim i as Long
Dim j as Long
Dim CurrentMode as Long ' scale mode of ListView
Dim TextSize as TextSize_t ' struct returned from API
Dim ColCount as Integer ' number of Columns
Dim ColSubItems as Integer ' number of SubItems
Dim ColSize() as Long ' sizes of ColumnHeaders

Dim HandleDeviceContext as Long
Dim sizeRet as Long

' setup
HandleDeviceContext = me.hdc

CurrentMode = me.ScaleMode
me.ScaleMode = 3 ' pixels
ColCount = ListView1.ColumnHeaders.Count
ColSubItems = ColCount - 1 ' = "size" column
ReDim ColSize(ColCount)

' col Header sizes
for i = 0 to ListView1.ColumnHeaders.Count
' you may wish to check the text of all the columnHeaders to see
' if they are the widest item...
next i

' ListItem sizes
for i = 1 to ListView1.ListItems.Count
' this is the only real secret here..
' This API call returns how big the text is,
' whether it is fully displayed or not
sizeRet = GetTextExtentPoint32(HandleDeviceContext, ListView1.ListItems(i), _
len(ListView1.ListItems(i)), TextSize)
ListView1.ListItems(i).SubItems(ColSubItems) = TextSize.cx & " , " & TextSize.cy

If TextSize.cx > ColSize(1) then
ColSize(1) = TextSize.cx ' save the largest value
End If

for j = 1 to ColSubItems
' look through each subitem for it's width
sizeRet = GetTextExtentPoint32(HandleDeviceContext, _
ListView1.ListItems(i).SubItems(j), _
len(ListView1.ListItems(i).SubItems(j)), _
TextSize)

If TextSize.cx > ColSize(j + 1) then
ColSize(j + 1) = TextSize.cx ' save the largest subitem
End If
next j

next i

' resize all cols as necessary
for i = 1 to ListView1.ColumnHeaders.Count
If ListView1.ColumnHeaders(i).Width < ColSize(i) then
' commented out next line for exact resize
' ListView1.ColumnHeaders(i).Width = ColSize(i) * 1.2
End If
next i
' OR
' resize all cols to fit exactly as needed
for i = 1 to ListView1.ColumnHeaders.Count
'1.2 seems to be the money scaling number for full visibility
ListView1.ColumnHeaders(i).Width = ColSize(i) * 1.2
next i

' for some reason, the last column always needs an extra increase in width
' I don't know why?
ListView1.ColumnHeaders(ListView1.ColumnHeaders.Count).Width = _
ListView1.ColumnHeaders(ListView1.ColumnHeaders.Count).Width * 1.15

' cleanup
me.ScaleMode = CurrentMode

End Sub

private Sub Form_Load()
Dim LstX as ListItem
Dim ColmX as ColumnHeader

' set up the ListView
ListView1.View = lvwReport ' 3

set ColmX = ListView1.ColumnHeaders.Add
ColmX.Text = "Name"
ColmX.Width = 1000

set ColmX = ListView1.ColumnHeaders.Add
ColmX.Text = "Address"
ColmX.Width = 1000

set ColmX = ListView1.ColumnHeaders.Add
ColmX.Text = "Phone"
ColmX.Width = 1000

set ColmX = ListView1.ColumnHeaders.Add
ColmX.Text = "size"
ColmX.Width = 1000

'populate the listview
set LstX = ListView1.ListItems.Add(, , "David Addison")
LstX.SubItems(1) = "125 Mercury Plaza"
LstX.SubItems(2) = "1234-5678"

set LstX = ListView1.ListItems.Add(, , "Allice Beasley")
LstX.SubItems(1) = "305 Boulevard"
LstX.SubItems(2) = "234-567-8900"

set LstX = ListView1.ListItems.Add(, , "Catherine Le Blank")
LstX.SubItems(1) = "801 Tejas Avenue"
LstX.SubItems(2) = "011-005-017-6067"

set LstX = ListView1.ListItems.Add(, , "Charles Grady")
LstX.SubItems(1) = "571 Hellena Court"
LstX.SubItems(2) = "909-090-9090"

set LstX = ListView1.ListItems.Add(, , "Harold Tice")
LstX.SubItems(1) = "21 Division Street"
LstX.SubItems(2) = "707-070-0077"

End Sub

This should give you a full demo project.
But, like it says in the code the real work is done by GetTextExtentPoint32