Private Function ListViewContains(ByVal Value As String) As Boolean
        For Each l As ListViewItem In Me.ListView1.Items
            If l.Text.ToUpper.Equals(Value) Then Return True
        Next
        Return False
    End Function

Dim a As New ArrayList
[...]
Dim item As String = ".."
If Not a.Contains(item) Then
   Me.ListView1.Items.Add(item)
   a.Add(item)
[...]