codice:
Partial Class prove_a
    Inherits System.Web.UI.Page


    Private rnd As Random = Nothing

    Protected Sub Button1_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles Button1.Click
        'Dim db As New DataAdmin

        rnd = New Random(CInt(Date.Now.Ticks And Integer.MaxValue))

        For i As Integer = 1 To 10
            Response.Write(myrnd() & "
")
        Next

    End Sub

    Function myrnd() As String

        Dim numero As Integer, arrLettere As New ArrayList

        arrLettere.Add("A")
        arrLettere.Add("B")
        arrLettere.Add("C")
        arrLettere.Add("D")
        arrLettere.Add("E")
        arrLettere.Add("F")
        arrLettere.Add("G")
        arrLettere.Add("H")
        arrLettere.Add("I")
        arrLettere.Add("J")
        arrLettere.Add("K")
        arrLettere.Add("L")
        arrLettere.Add("M")
        arrLettere.Add("N")
        arrLettere.Add("O")
        arrLettere.Add("P")
        arrLettere.Add("Q")
        arrLettere.Add("R")
        arrLettere.Add("S")
        arrLettere.Add("T")
        arrLettere.Add("U")
        arrLettere.Add("V")
        arrLettere.Add("W")
        arrLettere.Add("X")
        arrLettere.Add("Y")
        arrLettere.Add("Z")


        '1 numero
        numero = rnd.Next(0, 9)
        Dim password = CStr(numero)
        '2 lettere
        numero = rnd.Next(0, 25)
        password &= arrLettere(numero)
        numero = rnd.Next(0, 25)
        password &= arrLettere(numero)
        '2 numeri
        numero = rnd.Next(10, 99)
        password &= CStr(numero)
        '1 lettera
        numero = rnd.Next(0, 25)
        password &= arrLettere(numero)
        '3 numeri
        numero = rnd.Next(100, 999)
        password &= CStr(numero)
        '1 lettera
        numero = rnd.Next(0, 25)
        password &= arrLettere(numero)


        Return password

    End Function

End Class