[VB8]Aiuto per fixare funzione di controllo

[kerberos5]

Ciao a tutti,
sto facendo un piccolo software che mi randomizza lettere e numeri in delle label... ora vorrei eliminare i doppioni.... e pensavo utilizzare una funzione (che mi da dei problemi) che mi controllasse una ad una tutte le etichette... vi posto il codice per più facile comprensione:

Public Class frmMain

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Timer1.Enabled = True
        Timer1.Start()


    End Sub


    Private Sub Timer2_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer2.Tick
        Timer1.Stop()
        Timer1.Enabled = False
        Timer2.Stop()
        Timer2.Enabled = False

    End Sub

    Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick


        lblA.Text = GenKey.rndLetters(1)
        lblB.Text = GenKey.rndLetters(1)
        lblC.Text = GenKey.rndLetters(1)
        lblD.Text = GenKey.rndLetters(1)
        lblE.Text = GenKey.rndLetters(1)
        lblF.Text = GenKey.rndLetters(1)
        lblG.Text = GenKey.rndLetters(1)
        lblH.Text = GenKey.rndLetters(1)
        lblI.Text = GenKey.rndLetters(1)
        lblL.Text = GenKey.rndLetters(1)
        lblM.Text = GenKey.rndLetters(1)
        lblN.Text = GenKey.rndLetters(1)
        lblO.Text = GenKey.rndLetters(1)
        lblP.Text = GenKey.rndLetters(1)
        lblQ.Text = GenKey.rndLetters(1)
        lblR.Text = GenKey.rndLetters(1)
        lblS.Text = GenKey.rndLetters(1)
        lblT.Text = GenKey.rndLetters(1)
        lblU.Text = GenKey.rndLetters(1)
        lblV.Text = GenKey.rndLetters(1)
        lblZ.Text = GenKey.rndLetters(1)



        lbl1.Text = GenKey.rndNumber(1)
        lbl2.Text = GenKey.rndNumber(1)
        lbl3.Text = GenKey.rndNumber(1)
        lbl4.Text = GenKey.rndNumber(1)
        lbl5.Text = GenKey.rndNumber(1)
        lbl6.Text = GenKey.rndNumber(1)
        lbl7.Text = GenKey.rndNumber(1)
        lbl8.Text = GenKey.rndNumber(1)
        lbl9.Text = GenKey.rndNumber(1)
        lbl10.Text = GenKey.rndNumber(1)
        lbl11.Text = GenKey.rndNumber(1)
        lbl12.Text = GenKey.rndNumber(1)
        lbl13.Text = GenKey.rndNumber(1)
        lbl14.Text = GenKey.rndNumber(1)
        lbl15.Text = GenKey.rndNumber(1)
        lbl16.Text = GenKey.rndNumber(1)
        lbl17.Text = GenKey.rndNumber(1)
        lbl18.Text = GenKey.rndNumber(1)
        lbl19.Text = GenKey.rndNumber(1)
        lbl20.Text = GenKey.rndNumber(1)
        lbl21.Text = GenKey.rndNumber(1)

        Timer2.Enabled = True
        Timer2.Start()
    End Sub

    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        End
    End Sub

    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        controlla(lblA.Text)
    End Sub
End Class

Module GenKey

    Public Function rndLetters(ByVal length As Integer) As String

        Dim sb As New System.Text.StringBuilder
        Dim chars() As String = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "L", _
                                 "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "Z"}
        Dim upperBound As Integer = UBound(chars)

        For x As Integer = 1 To length
            sb.Append(chars(Int(Rnd() * upperBound)))
        Next

        Return sb.ToString

    End Function

    Public Function rndNumber(ByVal length As Integer) As String

        Dim sb As New System.Text.StringBuilder
        Dim chars() As String = {"01", "02", "03", "04", "05", "06", "07", "08", "09", "10", "11", "12", _
                                 "13", "14", "15", "16", "17", "18", "19", "20", "21"}
        Dim upperBound As Integer = UBound(chars)

        For x As Integer = 1 To length
            sb.Append(chars(Int(Rnd() * upperBound)))
        Next

        Return sb.ToString
    End Function

'funzione che controlla l'array di etichette in funzione del testo generato...
    Public Function controlla(ByVal path As String) As Boolean
        Dim myArray() As String = {frmMain.lblA.Text, frmMain.lblB.Text, frmMain.lblC.Text, frmMain.lblD.Text, _
        frmMain.lblE.Text, frmMain.lblF.Text, frmMain.lblG.Text, frmMain.lblH.Text, frmMain.lblI.Text, _
        frmMain.lblL.Text, frmMain.lblM.Text, frmMain.lblN.Text, frmMain.lblO.Text, frmMain.lblP.Text, _
        frmMain.lblQ.Text, frmMain.lblR.Text, frmMain.lblS.Text, frmMain.lblT.Text, frmMain.lblU.Text, _
        frmMain.lblV.Text, frmMain.lblZ.Text}
        For Each path In myArray
            If String.Compare(path, myArray.ToString, 0, 2, True) = True Then

                Return True
                MsgBox(True)
            Else
                Return False
                MsgBox(False)
            End If
        Next
    End Function
End Module

grazie