Dim ts As String = _
"NAME             LEISTUNG          VON    BIS    VORGANG   ST OPT.DAT " & _
"BUCH.DAT"
 
Dim lengths As New List(Of Integer), last As Integer = -1
 
For i As Integer = 0 To ts.Length - 2
   If Char.IsSeparator(CChar(ts(i))) AndAlso 
      Not Char.IsSeparator(CChar(ts(i + 1))) Then
          lengths.Add(i - last)
          last = i
   End If
Next i
lengths.Add(ts.Length - 1 - last)