protected void cboPayTypes_SelectedIndexChanged(object sender, EventArgs e)
    {
        try
        {
            string paytypecode = cboPayTypes.SelectedValue.ToString();
            if (paytypecode.Equals("0"))
            {
                Button1.Enabled = false;
            }
            else
            {
                dataTable = datafile.GetPayTypesByShortName(paytypecode);
                if (dataTable.Rows.Count > 0)
                {
                    Button1.Enabled = true;
                    string name    = dataTable.Rows[0]["PaymentType"].ToString();
                    bool   Vatable = bool.Parse(dataTable.Rows[0]["Vatable"].ToString());
                    double amount  = double.Parse(dataTable.Rows[0]["Amount"].ToString());

                    txtamount.Text    = amount.ToString("#,##0");
                    lblvat.Text       = Vatable.ToString();
                    txtpayingfor.Text = name;
                }
                else
                {
                    Button1.Enabled = false;
                }
            }
        }
        catch (Exception ex)
        {
            ShowMessage(ex.Message, true);
        }
    }