Visual Basic 2008 Hilfe pls

Public Class Form1

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        TextBox1.Clear()
        Dim rnd As New Random
        For i As Integer = 0 To 31
            If i = 8 Or i = 14 Or i = 16 Or i = 18 Or i = 24 Then
                TextBox1.Text &= "-"
            End If
            [B]TextBox1.Text() &= rnd.Next(3, 22)[/B]
        Next
    End Sub
End Class

 Dim i As Integer
        Dim nValue As Integer = 20 ' hier wieviele zeichen es haben soll
        Dim sKey As String = String.Empty

        For i = 1 To nValue

            Randomize()
            nValue = Int(1000 * Rnd())
            If (nValue Mod 10 = 0) Or (nValue Mod 5 = 0) Or (nValue Mod 3 = 0) Then
                ' Zahl          
                Randomize()
                Do
                    nValue = Int(8 * Rnd() + 1)
                Loop Until nValue >= 1 And nValue <= 9
                sKey = sKey & Chr(48 + nValue)

            Else
                ' Buchstabe       
                Randomize()
                Do
                    nValue = Int(26 * Rnd())
                Loop Until nValue >= 1 And nValue <= 26 And nValue <> 14 And nValue <> 21
                sKey = sKey & Chr(64 + nValue)


            End If
        Next i
  
        TextBox1.Text = sKey