async void RefreshGrid() { var datas = await tablehelper.GetCCTVData(); GvData.DataSource = datas; GvData.DataBind(); if (GvData.Rows.Count > 0) { //This replaces <td> with <th> GvData.UseAccessibleHeader = true; //This will add the <thead> and <tbody> elements GvData.HeaderRow.TableSection = TableRowSection.TableHeader; //This adds the <tfoot> element. Remove if you don't have a footer row GvData.FooterRow.TableSection = TableRowSection.TableFooter; } }