This is the code. It is maintaining the persistence.But i am not able to write code on insert button on web form. When i tried writing for insert button using sqlbulk command it inserted only the last page records. As i had erased that code there only so its not present in this code. 
protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                this.GetData();
            }
        }
        protected void PaginateTheData(object sender, GridViewPageEventArgs e)
        {
            List<int> list = new List<int>();
            if (ViewState["SelectedRecords"] != null)
            {
                list = (List<int>)ViewState["SelectedRecords"];
            }
            foreach (GridViewRow row in GridView1.Rows)
            {
                CheckBox chk = (CheckBox)row.FindControl("chkSelect");
                var selectedKey =
                int.Parse(GridView1.DataKeys[row.RowIndex].Value.ToString());
                if (chk.Checked)
                {
                    if (!list.Contains(selectedKey))
                    {
                        list.Add(selectedKey);
                    }
                }
                else
                {
                    if (list.Contains(selectedKey))
                    {
                        list.Remove(selectedKey);
                    }
                }
            }
            ViewState["SelectedRecords"] = list;
            GridView1.PageIndex = e.NewPageIndex;
            this.GetData();
        }

        /// <summary> 
        /// Gets the data. 
        /// </summary> 
        private void GetData()
        {
         //   DataTable table = new DataTable();
            // get the connection 

            using (con)
            {
                using (SqlCommand cmd = new SqlCommand("Select fid, fname from tblfaculty", con))
                {
                    using (SqlDataAdapter da = new SqlDataAdapter())
                    {

                        con.Open();
                        da.SelectCommand = cmd;
                        using (DataTable dt = new DataTable())
                        {
                            da.Fill(dt);

                            GridView1.DataSource = dt;
                            GridView1.DataBind();
                        }
                    }
                }
            }
        }
           // GridView1.DataSource = table;
           // GridView1.DataBind();
        

        /// <summary> 
        /// Gets the selected records. 
        /// </summary> 
        /// <param name="sender">The sender.</param> 
        /// <param name="e">The <see cref="System.EventArgs"/>
        ///    instance containing the event data.</param> 
        protected void GetSelectedRecords(object sender, EventArgs e)
        {
            Response.Write("<h3>Selected records</h3>");
            List<int> list = ViewState["SelectedRecords"] as List<int>;
            if (list != null)
            {
                foreach (int id in list)
                {
                    Response.Write(id.ToString() + "<br />");
                }
            }
        }

        /// <summary> 
        /// Looks for selection. 
        /// </summary> 
        /// <param name="sender">The sender.</param> 
        /// <param name="e">The <seecref="System.Web.UI.WebControls.GridViewRowEventArgs"/>
        ///     instance containing the event data.</param> 
        protected void ReSelectSelectedRecords(object sender, GridViewRowEventArgs e)
        {
            List<int> list = ViewState["SelectedRecords"] as List<int>;
            if (e.Row.RowType == DataControlRowType.DataRow && list != null)
            {
                var autoId = int.Parse(GridView1.DataKeys[e.Row.RowIndex].Value.ToString());
                if (list.Contains(autoId))
                {
                    CheckBox chk = (CheckBox)e.Row.FindControl("chkSelect");
                    chk.Checked = true;
                }
            }
        }

        protected void GridView1_SelectedIndexChanged(object sender, EventArgs e)
        {

        }
    }
}