Imports System

Imports System.Text.REgularExpressions

Public Module Module1

    Public Sub Main()

        Dim frase = "Selezionare il valore[OPTION]xxx | tttt| tttttt | dfdfdf| dfdfdf[OPTION]ererer | fdfdf| ererdfdf | dfdfdcv| dfdfd"

        'Soluzione #1: con espressioni regolari

        Dim regex As New Regex("(.*?)(\[OPTION\]|$)")

        Dim matches = regex.Matches(frase)

        For Each match in matches

            Console.WriteLine(match.Groups(1).Value)

        Next

        'Soluzione #2: con string.split

        Dim parti = frase.Split(new String() {"[OPTION]"}, StringSplitOptions.None)

        For Each parte in parti

            Console.WriteLine(parte)

        Next    

    End Sub

End Module