please Correct this code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;

public partial class GridViewCellsEdit : System.Web.UI.Page
{
    private const int _firstEditCellIndex = 2;

    #region Page Load
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            _sampleData = null;
            this.GridView1.DataSource = _sampleData;
            this.GridView1.DataBind();
        }