public ExcelFileResult ExportExcelDateWise(String from, string to)
    {
        DataTable dt = cm.getDataTable("select * from vw_mail_report where ARH_DATE between '" + from + "' and '" + to + "'");
        ExcelFileResult actionResult = new ExcelFileResult(dt) { FileDownloadName = "MailReport.xls" };
        return actionResult;
    }

$scope.exportToExcel = function (fromdate, todate) {
            if (fromdate == "" && todate == "" || fromdate == null && todate == null) {
                window.location.href = "/Report/ExportExcel";
            }
            else {
                window.location.href = "/Report/ExportExcelDateWise";
            }
        }