how to get data in data gried view in this code

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

using System.Windows.Forms;

using System.Data.SqlClient;

namespace SAMPLE

{

public partial class EmpDeatils : Form

{

public EmpDeatils()

{

InitializeComponent();

}

SqlConnection con;

SqlCommand cmd;

SqlDataReader dr;

DataSet ds;

SqlDataAdapter da;

SqlCommandBuilder bldr;

private void EmpDeatils_Load(object sender, EventArgs e)

{

con = new SqlConnection("Data Source=(LocalDB)\v11.0;Integrated Security=True;Connect Timeout=3");

con.Open();

cmd = new SqlCommand("select * from table_name", con);

dr = cmd.ExecuteReader();

DataTable dt = new DataTable();

dt.Load(dr);

dataGridView1.DataSource = dt;

con.Close();

}

private void display()

{

da = new SqlDataAdapter("Select * from table_name", con);

ds = new DataSet();

da.MissingSchemaAction = MissingSchemaAction.AddWithKey;

da.Fill(ds, "table_name");

bldr = new SqlCommandBuilder(da);

dataGridView1.DataSource = ds.Tables["table_name"];

}

private void display_btn_Click(object sender, EventArgs e)

{

display();

}

private void button7_Click(object sender, EventArgs e)

{

this.Close();

}

private void btninsert_Click(object sender, EventArgs e)

{

con = new SqlConnection("Data Source=(LocalDB)\v11.0;Integrated Security=True;Connect Timeout=3");

con.Open();

int aa = Convert.ToInt32(TXTEMP_ID.Text);

string bb = TXTEMP_NAME.Text;

int cc = Convert.ToInt32(TXTSALARY.Text);

cmd = new SqlCommand("INSERT INTO table_name(Emp_ID, Emp_Name,Salary) VALUES ('" + aa + "','" + bb + "','" + cc + "')", con);

cmd.ExecuteNonQuery();

MessageBox.Show("one record inserted:");

con.Close();

display();

}

private void button3_Click(object sender, EventArgs e)

{

con = new SqlConnection("Data Source=(LocalDB)\v11.0;Integrated Security=True;Connect Timeout=3");

con.Open();

int aa = Convert.ToInt32(TXTEMP_ID.Text);

cmd = new SqlCommand("DELETE FROM table_name where Emp_ID='" + aa + "'", con);

cmd.ExecuteNonQuery();

MessageBox.Show("one record Delete:");

con.Close();

display();

}

private void btnupdate_Click(object sender, EventArgs e)

{

con = new SqlConnection("Data Source=(LocalDB)\v11.0;Integrated Security=True;Connect Timeout=3");

con.Open();

int aa = Convert.ToInt32(TXTEMP_ID.Text);

string bb = TXTEMP_NAME.Text;

int cc = Convert.ToInt32(TXTSALARY.Text);

string abc = "UPDATE table_name SET Emp_ID ='" + aa + "', Emp_Name ='" + bb + "',Salary ='" + cc + "' WHERE Emp_ID = '" + aa + "'";

SqlCommand cmd = new SqlCommand(abc, con);

cmd.ExecuteNonQuery();

MessageBox.Show("one record updated:");

con.Close();

display();

}

private void btnsearch_Click(object sender, EventArgs e)

{

con.Open();

int aa = Convert.ToInt32(TXTEMP_ID.Text);

string abc = "SELECT Emp_ID,Emp_Name,Salary FROM table_name where Emp_ID='" + aa + "'";

cmd = new SqlCommand(abc, con);

MessageBox.Show("one record search:");

dr = cmd.ExecuteReader();

DataTable dt = new DataTable();

dt.Load(dr);

dataGridView1.DataSource = dt;

con.Close();

}

private void btntotalrecord_Click(object sender, EventArgs e)

{

con.Open();

cmd = new SqlCommand("select Count(*) from Employee", con);

int a = (int)cmd.ExecuteScalar();

label4.Text = "Total Record:--> " + a.ToString();

con.Close();

}

}

}