Gridview to Excel

public partial class how_Export_GridView_to_Excel_c : System.Web.UI.Page

{

public override void VerifyRenderingInServerForm(Control control)
{
}
private void ExportToExcel(string strFileName, GridView dg)
{ Response.Clear();
Response.Buffer = true;
Response.ContentType = "application/vnd.ms-excel";
Response.Charset = "";
this.EnableViewState = false;
System.IO.StringWriter oStringWriter = new System.IO.StringWriter(); System.Web.UI.HtmlTextWriter oHtmlTextWriter = new System.Web.UI.HtmlTextWriter(oStringWriter);
GridView1.RenderControl(oHtmlTextWriter);
Response.Write(oStringWriter.ToString());
Response.End(); }

protected void ImageButton1_Click1(object sender, ImageClickEventArgs e)
{
ExportToExcel("Report.xls", GridView1);

}


}