How can we export the data of GRIDVIEW in to microsoft EXCEL sheet`

Response.Clear();
Response.Charset = "";
Response.ContentType = "application/vnd.ms-excel";
Response.AppendHeader("content-disposition", "attachment; filename=ExportData.xls");
System.IO.StringWriter sw = new System.IO.StringWriter();
System.Web.UI.HtmlTextWriter hw = new System.Web.UI.HtmlTextWriter(sw);
GridView gv = new GridView();
gv.DataSource = dt; // assign your datatable here that you assign to grid.
gv.DataBind();
gv.RenderControl(hw);
Response.Write(sw.ToString());
Response.End();