.NET Getbetween Function

Function GetBetween(ByRef strSource As String, ByRef strStart As String, ByRef strEnd As String, _
    Optional ByRef startPos As Integer = 0) As String
  Dim iPos As Integer, iEnd As Integer, lenStart As Integer = strStart.Length
  Dim strResult As String
  strResult = String.Empty
  iPos = strSource.IndexOf(strStart, startPos)
  iEnd = strSource.IndexOf(strEnd, iPos + lenStart)
  If iPos <> -1 AndAlso iEnd <> -1 Then
    strResult = strSource.Substring(iPos + lenStart, iEnd - (iPos + lenStart))
  End If
  Return strResult
    End Function