Using ViewState to increase the Performance in Asp.Net GridVIew while retrieving SharePoint Data

Ascx

<%@ Assembly Name="$SharePoint.Project.AssemblyFullName$" %> <%@ Assembly Name="Microsoft.Web.CommandUI, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %> <%@ Register Tagprefix="SharePoint" Namespace="Microsoft.SharePoint.WebControls" Assembly="Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %> <%@ Register Tagprefix="Utilities" Namespace="Microsoft.SharePoint.Utilities" Assembly="Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %> <%@ Register Tagprefix="asp" Namespace="System.Web.UI" Assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" %> <%@ Import Namespace="Microsoft.SharePoint" %> <%@ Register Tagprefix="WebPartPages" Namespace="Microsoft.SharePoint.WebPartPages" Assembly="Microsoft.SharePoint, Version=14.0.0.0, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %> <%@ Control Language="C#" AutoEventWireup="true" CodeBehind="AjaxTestingNewUserControl.ascx.cs" Inherits="AjaxTestingNew.AjaxTestingNew.AjaxTestingNewUserControl"  %>  <%@ Register Assembly="AjaxControlToolkit, Version=3.0.30930.28736, Culture=neutral, PublicKeyToken=28f01b0e84b6d53e" Namespace="AjaxControlToolkit" TagPrefix="AjaxControlToolkit" %> <asp:UpdatePanel ID="UpdatePanel1" runat="server"> <ContentTemplate> <table width="100%" cellpadding="0" cellspacing="0"> <tr> <td> <asp:GridView ID="sgvCountries" runat="server" AutoGenerateColumns="False"     Width="100%"     CellPadding="4" EnableModelValidation="True" ForeColor="#333333"     GridLines="Both" AllowPaging="True"  PageSize="20"         onpageindexchanging="sgvCountries_PageIndexChanging">     <AlternatingRowStyle BackColor="White" /> <Columns> <asp:BoundField HeaderText="Country" DataField="Title" /> <asp:BoundField HeaderText="Region" DataField="Region" /> </Columns>     <EditRowStyle BackColor="#7C6F57" />     <FooterStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />     <HeaderStyle BackColor="#1C5E55" Font-Bold="True" ForeColor="White" />     <PagerSettings Mode="NextPrevious" NextPageText="Next"         PreviousPageText="Previous" />     <PagerStyle BackColor="#666666" ForeColor="White" HorizontalAlign="Center" />     <RowStyle BackColor="#E3EAEB" />     <SelectedRowStyle BackColor="#C5BBAF" Font-Bold="True" ForeColor="#333333" /> </asp:GridView> </td> </tr> </table> <asp:Label ID="lblMessage" runat="server"></asp:Label> </ContentTemplate> </asp:UpdatePanel>

Ascx.cs

using System; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using Microsoft.SharePoint; using System.Security; using System.Data; using System.Linq; using System.Collections.Generic; namespace AjaxTestingNew.AjaxTestingNew {     public partial class AjaxTestingNewUserControl : UserControl     {         protected void Page_Load(object sender, EventArgs e)         {             if (!IsPostBack)             {                 AjaxTestingNewUserControl obj = new AjaxTestingNewUserControl();                 ViewState["SharePointData"] = obj.getData();                 sgvCountries.DataSource = ViewState["SharePointData"];                 sgvCountries.DataBind();             }         }         public DataTable getData()         {             SPWeb currentWeb = SPContext.Current.Web;             SPList lst = currentWeb.Lists["lst_Country"];             SPQuery sQuery = new SPQuery();             sQuery.Query = "<OrderBy><FieldRef Name='ID' Ascending='False' /></OrderBy>";             SPListItemCollection myColl = lst.GetItems(sQuery);             return myColl.GetDataTable();         }         protected void sgvCountries_PageIndexChanging(object sender, GridViewPageEventArgs e)         {             if (ViewState["SharePointData"] != null)             {                 sgvCountries.DataSource = ViewState["SharePointData"];                 sgvCountries.PageIndex = e.NewPageIndex;                 sgvCountries.DataBind();             }         }    } }