Dim cCol As Integer = -1
 
    Private Sub ListView1_ColumnClick(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.ColumnClickEventArgs) Handles listView1.ColumnClick
        If cCol = e.Column Then
            If listView1.Sorting = SortOrder.Descending Then
                listView1.Sorting = System.Windows.Forms.SortOrder.Ascending
            Else
                listView1.Sorting = System.Windows.Forms.SortOrder.Descending
            End If
        Else
            listView1.Sorting = System.Windows.Forms.SortOrder.Ascending
        End If
        cCol = e.Column
        listView1.ListViewItemSorter = New lvsort1(e.Column)
    End Sub

    Implements IComparer
 
    Dim columnNum As Integer
 
    Sub New(ByVal column_to_sort As Integer)
        columnNum = column_to_sort
    End Sub
 
    Public Function Compare(ByVal a As Object, ByVal b As Object) As Integer _
      Implements IComparer.Compare
        Dim listItemA As System.Windows.Forms.ListViewItem
        listItemA = CType(a, System.Windows.Forms.ListViewItem)
 
        Dim listItemB As System.Windows.Forms.ListViewItem
        listItemB = CType(b, System.Windows.Forms.ListViewItem)
 
        Return Compare(listItemA.SubItems(columnNum).Text, listItemB.SubItems( _
          columnNum).Text, listItemA.ListView.Sorting = _
          System.Windows.Forms.SortOrder.Ascending)
    End Function
 
    Private Function compare(ByVal a As String, ByVal b As String, ByVal asc As _
      Boolean) As Integer
        Dim an As Long
        Dim bn As Long
        Dim res As Integer
        Debug.WriteLine("a=" + a + " b=" + b)
        Try
            an = CLng(a)
            bn = CLng(b)
            res = IIf(an < bn, -1, IIf(an > bn, 1, 0))
        Catch
 
            res = String.Compare(a, b)
        End Try
        Return IIf(asc, res, -res)
    End Function
 
End Class