ASP.Net 2.0: Export GridView to Excel

Please have a look here.
http://www.c-sharpcorner.com/UploadFile/DipalChoksi/exportxl_asp2_dc11032006003657AM/exportxl_asp2_dc.aspx

http://www.aspsnippets.com/post/2009/03/14/Export-GridView-To-WordExcelPDFCSV-in-ASPNet.aspx

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.IO;
using System.Reflection;
public partial class KB : System.Web.UI.Page
{
    Hashtable htControls = new Hashtable();
    protected void Page_Load(object sender, EventArgs e)
    {
        htControls.Add("LinkButton", "Text");
        htControls.Add("HyperLink", "Text");
        htControls.Add("DropDownList", "SelectedItem");
        htControls.Add("CheckBox", "Checked");
        htControls.Add("TextBox", "Text");
        htControls.Add("Button", "");
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        PrepareGridViewForExport(GridView1);
        ExportGridView();
    }
    private void ExportGridView()
    {
        string attachment = "attachment; filename=Contacts.xls";
        Response.ClearContent();
        Response.AddHeader("content-disposition", attachment);
        Response.ContentType = "application/ms-excel";
        StringWriter sw = new StringWriter();
        HtmlTextWriter htw = new HtmlTextWriter(sw);
        HtmlForm hf = new HtmlForm();
        GridView1.Parent.Controls.Add(hf);
        hf.Attributes.Add("runat", "server");
        hf.Controls.Add(GridView1);
        hf.RenderControl(htw);
        Response.Write(sw.ToString());
        Response.End();
    }


    private void PrepareGridViewForExport(Control gv)
    {
        Literal l = new Literal();
        for (int i = 0; i < gv.Controls.Count; i++)
        {
            if ((null != htControls[gv.Controls[i].GetType().Name]) || 
                (null != htControls[gv.Controls[i].GetType().BaseType.Name]))
            {
                l.Text = GetControlPropertyValue(gv.Controls[i]);
                gv.Controls.Remove(gv.Controls[i]);
                gv.Controls.AddAt(i, l);
            }
            if (gv.Controls[i].HasControls())
            {
                PrepareGridViewForExport(gv.Controls[i]);
            }
        }
    }
    private string GetControlPropertyValue(Control control)
    {
        Type controlType = control.GetType();
        string strControlType = controlType.Name;
        string strReturn = "Error";
        bool bReturn;
        PropertyInfo[] ctrlProps = controlType.GetProperties();

        string ExcelPropertyName = (string)htControls[strControlType];

        if (ExcelPropertyName == null)
        {
            ExcelPropertyName = (string)htControls[control.GetType().BaseType.Name];
            if (ExcelPropertyName == null)
                return strReturn;
        }
        foreach (PropertyInfo ctrlProp in ctrlProps)
        {
            if (ctrlProp.Name == ExcelPropertyName &&
            ctrlProp.PropertyType == typeof(String))
            {
                try
                {
                    strReturn = (string)ctrlProp.GetValue(control, null);
                    break;
                }
                catch
                {
                    strReturn = "";
                }
            }
            if (ctrlProp.Name == ExcelPropertyName &&
            ctrlProp.PropertyType == typeof(bool))
            {
                try
                {
                    bReturn = (bool)ctrlProp.GetValue(control, null);
                    strReturn = bReturn ? "True" : "False";
                    break;
                }
                catch
                {
                    strReturn = "Error";
                }
            }
            if (ctrlProp.Name == ExcelPropertyName &&
            ctrlProp.PropertyType == typeof(ListItem))
            {
                try
                {
                    strReturn = ((ListItem)(ctrlProp.GetValue(control, null))).Text;
                    break;
                }
                catch
                {
                    strReturn = "";
                }
            }
        }
        return strReturn;
    }
}

//Code2

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.IO;
using System.Reflection;
public partial class KB2 : System.Web.UI.Page
{
    protected void Button1_Click(object sender, EventArgs e)
    {
        ExportGridView();
    }
    private void ExportGridView()
    {
        string attachment = "attachment; filename=Contacts.xls";
        Response.ClearContent();
        Response.AddHeader("content-disposition", attachment);
        Response.ContentType = "application/ms-excel";
        StringWriter sw = new StringWriter();
        HtmlTextWriter htw = new HtmlTextWriter(sw);
        // Create a form to contain the grid
        GridView1.RenderControl(htw);
        Response.Write(sw.ToString());
        Response.End();
    }
    private void PrepareGridViewForExport(Control gv)
    {
        Literal l = new Literal();
        string name = String.Empty;
        string t = null;
        for (int i = 0; i < gv.Controls.Count; i++)
        {
            t = gv.Controls[i].GetType().Name;
            switch (t)
            {
                case "LinkButton":
                    RenderControlsContent(gv, i, l, (gv.Controls[i] as LinkButton).Text);
                    break;
                case "DropDownList":
                    RenderControlsContent(gv, i, l, (gv.Controls[i] as DropDownList).SelectedItem.Text);
                    break;
                case "CheckBox":
                    RenderControlsContent(gv, i, l, (gv.Controls[i] as CheckBox).Checked ? "True" : "False");
                    break;
                case "TextBox":
                    RenderControlsContent(gv, i, l, (gv.Controls[i] as TextBox).Text);
                    break;
            }
            if (gv.Controls[i].HasControls())
            {
                PrepareGridViewForExport(gv.Controls[i]);
            }
        }
    }
    private void RenderControlsContent(Control gv, int cindex, Literal l, string strValue)
    {
        l.Text = strValue;
        gv.Controls.Remove(gv.Controls[cindex]);
        gv.Controls.AddAt(cindex, l);
    }
}