Linq by query insert update delete search

Linq by query insert update delete search
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;

namespace linqbyquery
{
public partial class Form1 : Form
{
public Form1()
{

InitializeComponent();
dc = new DataClasses1DataContext();
}
DataClasses1DataContext dc;

private void btnadd_Click(object sender, EventArgs e)
{
employee em = new employee { code = Convert.ToInt32(txtdeptt.Text), name = txtname.Text, salary = Convert.ToInt32(txtsal.Text) };
dc.employees.InsertOnSubmit(em);
dc.SubmitChanges();
MessageBox.Show("insert");
//S();
}

private void btnupdate_Click(object sender, EventArgs e)
{
var em=dc.employees.Single( c=> c.code==1);
em.name = txtname.Text;
dc.SubmitChanges();
MessageBox.Show("update");
}

private void btndal_Click(object sender, EventArgs e)
{
var d = dc.employees.Where(c => c.code == 1).First();
dc.employees.DeleteOnSubmit(d);
dc.SubmitChanges();
MessageBox.Show("delete");

}

private void btnsearch_Click(object sender, EventArgs e)
{
var x = from c in dc.employees where c.code == 1 select c;
dg1.DataSource = x;

}
//public void S()
//{
// var ans = from * in dc.employees ;
// dg1.DataSource = ans;
//}
}
}