Public Function GetMaid() As Integer
        Dim x As Single = 1
        If Conn.State = ConnectionState.Closed Then
            Conn.Open()
        End If

        Dim adp As New OleDbCommand("select max (IDInvoices) from Invoices", Conn)
        Try
            x = adp.ExecuteScalar
            Return x + 1
        Catch ex As Exception
            Return x
            Conn.Close()
        End Try