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);
    }
}