How to get the total using crystal report

Hi Nar,

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.OleDb;
namespace Grade_Count
{
    public partial class Form1 : Form
    {
        string ConnectionString = System.Configuration.ConfigurationSettings.AppSettings["dsn"];
        OleDbCommand com;
        OleDbDataAdapter oledbda;
        string str;
        DataSet ds;

        public Form1()
        {
            InitializeComponent();
        }

        private void btn_total_Click(object sender, EventArgs e)
        {
            OleDbConnection con = new OleDbConnection(ConnectionString);
            con.Open();
            str = "select sum(Amt) from test";
            com = new OleDbCommand(str, con);
            txt_total_amount.Text = com.ExecuteScalar().ToString();
            con.Close();
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            OleDbConnection con = new OleDbConnection(ConnectionString);
            con.Open();
            str = "select * from test";
            com = new OleDbCommand(str, con);
            oledbda = new OleDbDataAdapter(com);
            ds = new DataSet();
            oledbda.Fill(ds, "test");
            dataGridView1.DataMember = "test";
            dataGridView1.DataSource = ds;
            con.Close();
        }   
    }
}



Thanks