How do I implement text spinning in vb.net!?

Function Spin(ByRef value As String) As String
        ' Invoke the Regex.Replace function.
        Return Regex.Replace(value, _
        "{.*?}", _
        New MatchEvaluator(AddressOf SpinEvaluator))
    End Function

    Function SpinEvaluator(ByVal match As Match) As String
        ' Get string from match.
        Dim v As String = match.ToString()

        If v.Contains("{") Then
            Dim x() As String = v.Split("|")

            Dim kwd As String = x(GetRandom(0, x.Length)).Replace("{", "").Replace("}", "")

            Return kwd
        Else
            Return v
        End If
    End Function

Function Tokenize(ByVal SourceString As String) As String
        Dim ReturnString As New StringBuilder
        Dim I As Integer = 0
        Randomize()
        Do While I < SourceString.Length
            Dim c As Char = SourceString.Chars(I)
            Select Case c
                Case ("{"c)
                    ReturnString.Append(Tokenize(SourceString.Substring(I + 1)))
                    Exit Do
                Case ("}"c)
                    Dim Options As String() = ReturnString.ToString().Split("|"c)
                    ReturnString = New StringBuilder
                    ReturnString.Append(Options(CType(Math.Floor(Rnd() * CType(Options.Length, Single)), Integer)))
                    If I < SourceString.Length - 1 Then
                        SourceString = SourceString.Substring(I + 1)
                        I = -1
                    Else
                        SourceString = ""
                    End If
                Case Else
                    ReturnString.Append(c)
            End Select
            I += 1
        Loop
        Return ReturnString.ToString()
    End Function

    Public Function GetRandom(ByVal Min As Integer, ByVal Max As Integer) As Integer
        Randomize()
        Return Int(Max * Rnd() + Min)

    End Function

    Public Function Spin(ByVal SourceString As String) As String
        '
        '    Create a temp return info
        '
        Dim ReturnString As New System.Text.StringBuilder
        '
        '    The loop position in the source string
        '
        Dim I As Integer = 0
        '
        '    Sart a new random sequence
        '
        Randomize()
        '
        '    While there is something in the source
        '
        Do While I < SourceString.Length
            '
            '    Get the char to process
            '
            Dim c As Char = SourceString.Chars(I)
            '
            '    Depending on the char
            '
            Select Case c
                Case "{"c
                    '
                    '    This is an opening so must start a deeper level
                    '
                    ReturnString.Append(Spin(SourceString.Substring(I + 1)))
                    Exit Do
                Case "}"c
                    '
                    '    This is a closing one.
                    '--------------------------------------------------------
                    '
                    '    calculate the options using the | separator
                    '
                    Dim Options As String() = ReturnString.ToString.Split("|"c)
                    '
                    '    Clear the return string to get an option. 
                    '
                    ReturnString = New System.Text.StringBuilder
                    '
                    '    Get the option
                    '
                    ReturnString.Append(Options(CType(Math.Floor(Rnd() * CType(Options.Length, Single)), Integer)))
                    '
                    '    Get hte rest of the string past the closing bracket
                    '
                    If I < SourceString.Length - 1 Then
                        '
                        '    Disregard all the source before the ending bracket and reset the pointer
                        '
                        SourceString = SourceString.Substring(I + 1)
                        I = -1
                    Else
                        '
                        '    If this is the last char, then nothing more to analyze
                        '
                        SourceString = ""
                    End If
                Case Else
                    '
                    '    this is a normal char
                    '
                    ReturnString.Append(c)
            End Select
            '
            '    Go for the next char
            '
            I += 1
        Loop
        '
        '    Return the valid string
        '
        Return ReturnString.ToString

    End Function

Imports System.Text.RegularExpressions

Public Class Form1

    Public rand As New Random() ' random function needs to be declared as a member to work as expected

    Public Function GetRandomItem(ByVal m As Match) As String
        ' split on the pipe symbol and get the random index based on the resulting array length
        Dim items As String() = m.Groups("Items").Value.Split("|")
        Dim randomIndex As Integer = rand.Next(0, items.Length)
        Return items(randomIndex)
    End Function


    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles spin2.Click
        Dim input As String
        input = RichTextBox1.Text
        Dim pattern As String = "{(?<Items>(?:.+?\|[^}]+))}"
        ' Using Replace with a MatchEvaluator
        Dim result As String = Regex.Replace(input, pattern, AddressOf GetRandomItem)
        RichTextBox2.Text = (result)

    End Sub
End Class

Private Function Spin(ByVal Data As String) As String
Try
 If Data.length = 0 Then Return ""
 Dim pattern As String = "{[^{}]*}"
 Dim m As Match = Regex.Match(Data, pattern)
 Dim seg As String = ""
 Dim val() As String = Nothing
 Dim rnd As New Random
 
 While m.Success
                seg = Data.Substring(m.Index + 1, m.Length - 2)
                val = Split(seg, "|")
                Data = Data.Substring(0, m.Index) & val(rnd.Next(val.Length)) & Data.Substring(m.Index + m.Length)
                m = Regex.Match(Data, pattern)
 End While
        pattern =  nothing
        m = Nothing
        seg = Nothing
        val = Nothing
        rnd = Nothing

Catch ex As Exception
'possible errors here are memory related.       
End Try
Return Data
End Function