i am getting error Exception type 'System.OutOfMemoryException' was thrown when exproting large data into excel.

Response.Clear();
Response.Buffer = true;
Response.ContentType = "application/ms=excel";
Response.AddHeader("content-disposition", string.Format("attachment;filename={0}.xls", "selectedrows"));
Response.Charset = "";
StringWriter stringwriter = new StringWriter();
HtmlTextWriter htmlwriter = new HtmlTextWriter(stringwriter);
GVallbb.RenderControl(htmlwriter);
Response.Write(stringwriter.ToString());
Response.End();