嵌套的gridview如何导出Excel

如果是单个gridview使用一下代码可以导出到excel
  Response.Clear();
  Response.Buffer = true;
  Response.Charset = "GB2312";
  Response.AppendHeader("Content-Disposition", "attachment;filename=kq.xls");
  Response.ContentType = "application/excel";
  EnableViewState = false;
  StringWriter swOut = new StringWriter();
  HtmlTextWriter hTw = new HtmlTextWriter(swOut);
  gvwData.RenderControl(hTw);
  Response.Write(swOut.ToString());
  ApplicationInstance.CompleteRequest();
  Response.Flush();
  Response.End();
如果嵌套了gridview则不能导出到excel，请各大能指教！

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