Update datagridview

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(); } } }