protected void btnCreateExcel_Click(object sender, EventArgs e) { //Step 1 : Instantiate the spreadsheet creation engine. ExcelEngine excelEngine = new ExcelEngine(); //Step 2 : Instantiate the excel application object. IApplication application = excelEngine.Excel; IWorkbook workbook = application.Workbooks.Create(1); //IWorkbook workbook = application.Workbooks.Create(1); IWorksheet sheet = workbook.Worksheets[0]; //Imports from GridView to worksheet. sheet.ImportGridView(gridView, 1, 1, chbHeader.Checked, chbStyle.Checked); sheet.UsedRange.AutofitColumns(); if (rdButtonXls.Checked) { application.DefaultVersion = ExcelVersion.Excel97to2003; workbook.SaveAs("Output.xls", ExcelSaveType.SaveAsXLS, Response, ExcelDownloadType.PromptDialog); } else if (rdButtonXlsx.Checked) { application.DefaultVersion = ExcelVersion.Excel2013; workbook.SaveAs("Output.xlsx", ExcelSaveType.SaveAsXLS, Response, ExcelDownloadType.PromptDialog); } workbook.Close(); excelEngine.Dispose(); }