I am building a Diner POS (practice project) and needed a fixed length string for the customer receipt (since product names are of variable lengths). Thought I'd share the code I found with you guys :)

    Public Function FixedLengthString(ByVal value As String,
                                      ByVal totalLength As Integer,
                                      ByVal padding As Char) As String

        Dim length = value.Length

        If (length > totalLength) Then Return value.Substring(0, totalLength)
        Return value.PadRight(totalLength, padding)

    End Function

Works great!