How to Fit all columns in a ListView in C#, VB.NET, and VB6

Code is shown below to Autofit the data in a listview for C#, VB.NET, and VB6:

C#

public void AutoFitListView(ListView lv)
{
   for (int i = 0; i <= lv.Columns.Count - 1; i++)     {          lv.Columns[i].Width = -2; // longest col head and item                                    // -1 for just longest item     } } 

VB.NET

Public Sub AutoFitListView(ByRef lv As ListView)

For i As Integer = 0 To lv.Columns.Count - 1

 lv.Columns(i).Width = -2

Next

End Sub

VB6
Unfortunately, the VB6 solution is a bit more complicated:

Private Const LVM_FIRST As Long = &H1000
Private Const LVM_SETCOLUMNWIDTH As Long = (LVM_FIRST + 30)
Private Const LVSCW_AUTOSIZE As Long = -1
Private Const LVSCW_AUTOSIZE_USEHEADER As Long = -2

Private Declare Function SendMessage Lib "user32" _
Alias "SendMessageA" _ (ByVal hwnd As Long, ByVal wMsg As Long, _ ByVal wParam As Long, lParam As Any) As Long

Public Sub AutoFitListView(lv As ListView)
   Dim i As Long

   For i = 0 To lv.ColumnHeaders.count - 1

        Call SendMessage(lv.hwnd, LVM_SETCOLUMNWIDTH, i, ByVal LVSCW_AUTOSIZE_USEHEADER)

   Next

End Sub

You can change the LVSCW_AUTOSIZE_USEHEADER to LVSCW_AUTOSIZE if you do not want to consider the Header when adjusting the size.

More examples of the VB6 approach can be found at:

http://vbnet.mvps.org/index.html?code/comctl/lvcolumnautosize.htm