เรียก auto id จากฐานข้อมูลแล้วขึ้นแบบนี้ครับ "Conversion from string "BG600182" to type 'Integer' is not valid."

Private Sub AutoGenerateMemberID()
        Dim ItemID As Integer
        Dim s As String = "select MAX( Bill_ID ) FROM Billing "
        Dim dr As OleDbDataReader
        dr = ExecuteReader(s)
        While dr.Read()
            ItemID = CInt(dr(0))
            ItemID = ItemID + 1
            tb_billingNo.Text = CStr(ItemID)
        End While
        dr.Close()
    End Sub
    Private Sub tb_billingNo_TextChanged(sender As Object, e As EventArgs) Handles tb_billingNo.TextChanged
        AutoGenerateMemberID()
    End Sub