RndStr not working yet

    Public Function RndStr()
        Dim s As String = "ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"
        Dim r As New Random
        Dim sb As New StringBuilder
        For i As Integer = 1 To 8
            Dim idx As Integer = r.Next(0, 35)
            sb.Append(s.Substring(idx, 1))
        Next
        Return (sb.ToString())
    End Function