gridview - How to export grid view to excel 2007 and above C# -

i'm trying export grid view excel 2007 , above file using excel package library on every time run export function file empty. i'm working on old code implemented else. @ first converting list anonymous object type that:

var exportdata = onpremisestransactionspagemodel.inclinictransactionslist.select(intrans => new             {                 billingid = intrans.financialtransactionid == 0 ? string.empty : "tr" + intrans.financialtransactionid,                 appointmentdate = intrans.appointmentdatetime == datetime.minvalue ? string.empty : intrans.appointmentdatetime.tostring("mm/dd/yyyy, hh:mm tt"),                 amount = intrans.amount == 0 ? string.empty : intrans.amount.tostring("c"),                 paymenttype = intrans.amount == 0 ? string.empty : ((intrans.paymentmethodtypeid == convert.toint32(preferredinclinicpaymentoption.cash)) ? intrans.paymentmethodtypename : intrans.paymentmethodprovidername),                 receivername = string.isnullorwhitespace(intrans.receivername) ? string.empty : intrans.receivername             }).tolist(); 

and binding grid view this:

string[] columnheaders= { resource.getstring("id"),                                        resource.getstring("transactiondatetime"),                                        resource.getstring("amount"),                                        resource.getstring("transactiondescription")                                      }; gridview.datasource = source;         gridview.rowdatabound += ((sender, e) => customizegridcolumnheaders(sender, e, columnheaders));         gridview.databind();      void customizegridcolumnheaders(object sender, gridviewroweventargs e, string[] columnheaders)     {         if ((e.row.rowtype == datacontrolrowtype.header) && ((columnheaders != null) && (columnheaders.length > 0)))         {             (int idx = 0, length = e.row.cells.count; idx < length; idx++)             {                 if (idx >= columnheaders.count())                 {                     continue;                 }                 e.row.cells[idx].text = columnheaders[idx];             }         }     } 

after using following code generate 97-2003 excel file , need generate file on 2007 or above versions

this implemented code previous team:

httpcontext curcontext = httpcontext.current;         curcontext.response.clear();         curcontext.response.addheader("content-disposition", "attachment;filename=inclinictransactions.xls");         curcontext.response.charset = "utf-8";         curcontext.response.cache.setcacheability(httpcacheability.nocache);         curcontext.response.contenttype = "application/vnd.ms-excel";  ////convert rendering of gridview string representation          stringwriter sw = new stringwriter();         system.web.ui.htmltextwriter htw = new htmltextwriter(sw);         gridview.rendercontrol(htw);            ////write response         curcontext.response.write(sw.tostring());         curcontext.response.flush();         curcontext.response.end(); 

and i'm trying this:

httpcontext curcontext = httpcontext.current;         curcontext.response.clear();         curcontext.response.addheader("content-disposition", "attachment;filename=inclinictransactions.xlsx");         curcontext.response.charset = "utf-8";         curcontext.response.cache.setcacheability(httpcacheability.nocache);         curcontext.response.contenttype = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";  datatable dt = new datatable();         (int idx = 0; idx <= gridview.headerrow.cells.count - 1; idx++)         {             dt.columns.add(gridview.headerrow.cells[idx].text.tostring());         }         (int = 0; < gridview.rows.count; i++)         {             datarow dr = dt.newrow();             (int j = 0; j <= gridview.rows[i].cells.count - 1; j++)             {                 if (!string.isnullorempty(gridview.rows[i].cells[j].text.tostring()))                 {                     dr[j] = gridview.rows[i].cells[j].text.tostring();                 }             }             dt.rows.add(dr);         }             using (excelpackage pck = new excelpackage())         {             excelworksheet wsdt = pck.workbook.worksheets.add("sheet1");             wsdt.cells["a1"].loadfromdatatable(dt, true, tablestyles.none);             wsdt.cells[wsdt.dimension.address].autofitcolumns();              curcontext.response.binarywrite(pck.getasbytearray());         }  curcontext.response.flush();         curcontext.response.end(); 

but on every time run function i'm getting file empty, don't know mistake , if can me please solve issue, , in advance.