Extracting SQL Connection

protected void insrt_btn_Click(object sender, EventArgs e)
{
    SqlConnection conn = new SqlConnection("Data Source=192.168.0.11;Initial Catalog=DataRecord;User ID=sa;Password=super");
    SqlCommand cmd = new SqlCommand();
    cmd.Connection = conn;
    cmd.CommandType = CommandType.Text;
    cmd.CommandText = "Insert into EntryTableTest(Name, [N.I.C], EntryDatetime, ToSee, PurposeOfVisit, VehicalNO) values('" + name_txt.Text + "','" + nic_txt.Text + "','" + System.DateTime.Now + "','" + tosee_txt.Text + "','" + pov_txt.Text + "','" + veh_txt.Text + "')";
    conn.Open();
    cmd.ExecuteNonQuery();
    bindGrid();
    conn.Close();
}
private void bindGrid()
{
    string connectionString = "Data Source=192.168.0.11;Initial Catalog=DataRecord;User ID=sa;Password=super";
    string sql = "SELECT * FROM EntryTableTest";

    using (var connection = new SqlConnection(connectionString))
    using (var command = new SqlCommand(sql, connection))
    using (var adapter = new SqlDataAdapter(command))
    {
        connection.Open();
        var dataEntry1 = new DataTable();
        adapter.Fill(dataEntry1);
        GridView1.DataSource = dataEntry1;
        GridView1.DataBind();
        GridView1.Visible = true;
    }