c# - Error in getting file using sharepoint designer 2010 programmatically -

error in getting file using sharepoint designer 2010 programmatically

protected void updatetemplate_1() {         spsite spsite = spcontext.current.site;         spweb spweb = spsite.openweb();         string filepath = "";             try           {             spweb.allowunsafeupdates = true;             splistitemcollection  listitems  = spweb.lists["captive report"].items;             string sitecol= spsite.url.tostring().trim();                foreach(splistitem lst11 in listitems)                 {                        filepath=lst11.url.tostring().trim(); //gets site-relative url of item                 }                 spfile file = spweb.getfile(filepath);                                                        system.io.fileinfo templatefile = new  system.io.fileinfo(@filepath);        using (officeopenxml.excelpackage pck = new officeopenxml.excelpackage(templatefile))   //officeopenxml.excelpackage(result, source)         {         int count = pck.workbook.worksheets.count;         response.write(count+"<br>");                byte[] filebytes = pck.getasbytearray();                 //byte[] filebytes = file.openbinary();                     response.clear();                  response.clearcontent();                  response.clearheaders();                  response.cookies.clear();                  //add header & other information                                   response.cache.setcacheability(httpcacheability.private);                  response.cachecontrol = "private";                  response.charset = system.text.utf8encoding.utf8.webname;                  response.contentencoding = system.text.utf8encoding.utf8;                  response.appendheader("content-length", filebytes.length.tostring());                  response.appendheader("pragma", "cache");                  response.appendheader("expires", "60");                  string filename = "filename_" + datetime.now.tostring("mmm").trim();// +".xlsx";                 response.appendheader("content-disposition",                 "attachment; " +                 "filename=\"" + filename + ".xlsx\"; "    //filename of excel                      );                  response.contenttype = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";                 //write client                                 response.binarywrite(filebytes);                   }            }     catch (exception ex)     {        response.write(ex.tostring());     } 

}

the workbook trying fetch has 3 worksheets,still giving worksheet count 0 (0), , hence while converting using getasbytearray, showing error :

system.invalidoperationexception: workbook must contain @ least 1 worksheet @ officeopenxml.excelworkbook.save() @ officeopenxml.excelpackage.getasbytearray(boolean save) at