How to Export Gridview to Excel.

Wrtie  the following Code in Export button:

protected void btnexport_Click(object sender, EventArgs e)

    {

        try

        {

            Response.Clear();

            Response.Buffer = true;

            Response.AddHeader("content-disposition", "attachment;filename=gridviewdata.xls");

            Response.Charset = "";

            Response.ContentType = "application/vnd.ms-excel";

            StringWriter sWriter = new StringWriter();

            HtmlTextWriter hWriter = new HtmlTextWriter(sWriter);

            GridView1.RenderControl(hWriter);

            Response.Output.Write(sWriter.ToString());

            Response.Flush();

            Response.End();

        }

        catch (Exception ex)

        {

            Label1.Text = ex.ToString();

        }

    }

//***********
public override void VerifyRenderingInServerForm(Control control)
 {
  }