how to do insert update and delete operation in datagridview in window application usin buttoncolumn inside datagridview

App.config

xml version="1.0" encoding="utf-8" ?>

<configuration>

<appSettings>

            <add key="dsn" value="Provider=Microsoft.Jet.OLEDB.4.0;Data Source=..\EMP.mdb" />

      appSettings>

configuration>

Form1.cs

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 Insert_Update_Delete_DataGridView

{

    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 Form1_Load(object sender, EventArgs e)

        {

            bindgrid();

        }

        private void bindgrid()

        {

            OleDbConnection con = new OleDbConnection(ConnectionString);

            con.Open();

            str = "select * from employee";

            com = new OleDbCommand(str, con);

            oledbda = new OleDbDataAdapter(com);

            ds = new DataSet();

            oledbda.Fill(ds, "employee");

            dataGridView1.DataMember="employee";

            dataGridView1.DataSource = ds;

            con.Close();

        }

        private void Clear()

        {

            txt_sno.Text = "";

            txt_name.Text = "";

            txt_address.Text = "";

            txt_age.Text = "";

        }

        private void btn_edit_Click(object sender, EventArgs e)

        {

            int i;

            i = dataGridView1.SelectedCells[0].RowIndex;

            txt_sno.Text = dataGridView1.Rows[i].Cells[1].Value.ToString();

            txt_name.Text = dataGridView1.Rows[i].Cells[2].Value.ToString();

            txt_address.Text = dataGridView1.Rows[i].Cells[3].Value.ToString();

            txt_age.Text = dataGridView1.Rows[i].Cells[4].Value.ToString();

        }

        private void btn_update_Click(object sender, EventArgs e)

        {

            OleDbConnection con = new OleDbConnection(ConnectionString);

            con.Open();

            str = "Update employee set sno=@sno,name=@name,address=@address,age=@age Where sno=@sno";

            com = new OleDbCommand(str, con);

            com.Parameters.AddWithValue("@sno", txt_sno.Text);

            com.Parameters.AddWithValue("@name", txt_name.Text);

            com.Parameters.AddWithValue("@address", txt_address.Text);

            com.Parameters.AddWithValue("@age", txt_age.Text);

            com.ExecuteNonQuery();

            MessageBox.Show("Record Successfully Updated");

            con.Close();

            bindgrid();

            Clear();

        }

        private void btn_delete_Click(object sender, EventArgs e)

        {

            OleDbConnection con = new OleDbConnection(ConnectionString);

            com = new OleDbCommand();

            if (dataGridView1.Rows.Count > 1 && dataGridView1.SelectedRows[0].Index != dataGridView1.Rows.Count - 1)

            {

                com.CommandText = "DELETE FROM employee WHERE ID=" + dataGridView1.SelectedRows[0].Cells[0].Value.ToString() + "";

                con.Open();

                com.Connection = con;

                com.ExecuteNonQuery();

                con.Close();

                dataGridView1.Rows.RemoveAt(dataGridView1.SelectedRows[0].Index);

                MessageBox.Show("Record Successfully Deleted");

            }

            bindgrid();

        }

        private void btn_insert_Click(object sender, EventArgs e)

        {

            OleDbConnection con = new OleDbConnection(ConnectionString);

            con.Open();

            str = "Insert into employee(sno,name,address,age) Values (@sno,@name,@address,@age)";

            com = new OleDbCommand(str, con);

            com.Parameters.AddWithValue("@sno", txt_sno.Text);

            com.Parameters.AddWithValue("@name", txt_name.Text);

            com.Parameters.AddWithValue("@address", txt_address.Text);

            com.Parameters.AddWithValue("@age", txt_age.Text);

            com.ExecuteNonQuery();

            con.Close();

            MessageBox.Show("Record Successfully Inserted");

            bindgrid();

            Clear();

        }

    }

}