public static byte[] ExportExcel(DataTable dataTable, string heading = "", string timeReport = "", string creater = "", bool showSrNo = false, params string[] columnsToTake)
        {
            byte[] result = null;
            using (ExcelPackage package = new ExcelPackage())
            {
                ExcelWorksheet workSheet    = package.Workbook.Worksheets.Add(String.Format("{0} Data", heading));
                int            startRowFrom = String.IsNullOrEmpty(heading) ? 1 : 3;
                // int columRow = 0;
                if (showSrNo)
                {
                    // columRow = 1;
                    DataColumn dataColumn = dataTable.Columns.Add("#", typeof(int));
                    dataColumn.SetOrdinal(0);
                    int index = 1;

                    foreach (DataRow item in dataTable.Rows)
                    {
                        item[0] = index;
                        index++;
                    }
                }


                //// headers
                //foreach (string header in columnsToTake)
                //{
                //    workSheet.Cells[startRowFrom , columRow].Value = header;
                //    columRow++;
                //}

                // add the content into the Excel file
                workSheet.Cells["A" + startRowFrom].LoadFromDataTable(dataTable, true);

                // autofit width of cells with small content
                int columnIndex = 1;
                foreach (DataColumn column in dataTable.Columns)
                {
                    ExcelRange columnCells = workSheet.Cells[workSheet.Dimension.Start.Row, columnIndex, workSheet.Dimension.End.Row, columnIndex];
                    int        maxLength   = columnCells.DefaultIfEmpty().Max(cell => cell.Value == null ? 0 : cell.Value.ToString().Count());
                    if (maxLength < 150)
                    {
                        workSheet.Column(columnIndex).AutoFit();
                    }


                    columnIndex++;
                }

                // format header - bold, yellow on black
                using (ExcelRange r = workSheet.Cells[startRowFrom, 1, startRowFrom, dataTable.Columns.Count])
                {
                    r.Style.Font.Color.SetColor(System.Drawing.Color.White);
                    r.Style.Font.Bold        = true;
                    r.Style.Fill.PatternType = OfficeOpenXml.Style.ExcelFillStyle.Solid;
                    r.Style.Fill.BackgroundColor.SetColor(System.Drawing.ColorTranslator.FromHtml("#1fb5ad"));
                }

                // format cells - add borders
                using (ExcelRange r = workSheet.Cells[startRowFrom + 1, 1, startRowFrom + dataTable.Rows.Count, dataTable.Columns.Count])
                {
                    r.Style.Border.Top.Style    = ExcelBorderStyle.Thin;
                    r.Style.Border.Bottom.Style = ExcelBorderStyle.Thin;
                    r.Style.Border.Left.Style   = ExcelBorderStyle.Thin;
                    r.Style.Border.Right.Style  = ExcelBorderStyle.Thin;

                    r.Style.Border.Top.Color.SetColor(System.Drawing.Color.Black);
                    r.Style.Border.Bottom.Color.SetColor(System.Drawing.Color.Black);
                    r.Style.Border.Left.Color.SetColor(System.Drawing.Color.Black);
                    r.Style.Border.Right.Color.SetColor(System.Drawing.Color.Black);
                }


                for (int i = dataTable.Columns.Count - 1; i >= 0; i--)
                {
                    if (i == 0 && showSrNo)
                    {
                        continue;
                    }
                    if (!columnsToTake.Contains(dataTable.Columns[i].ColumnName))
                    {
                        workSheet.DeleteColumn(i + 1);
                    }
                }

                if (!String.IsNullOrEmpty(creater))
                {
                    workSheet.Cells["A1"].Value = creater;
                    //workSheet.Cells[1, dataTable.Rows.Count].Merge = true;
                    workSheet.Cells["A1"].Style.Font.Size = 20;
                    //workSheet.InsertColumn(1, 1);
                    workSheet.InsertRow(1, 1);
                    workSheet.Column(1).Width = 5;
                }

                if (!String.IsNullOrEmpty(timeReport))
                {
                    workSheet.Cells["A1"].Value = timeReport;
                    // workSheet.Cells[1, dataTable.Rows.Count].Merge = true;
                    workSheet.Cells["A1"].Style.Font.Size = 20;
                    //workSheet.InsertColumn(1, 1);
                    workSheet.InsertRow(1, 1);
                    workSheet.Column(1).Width = 5;
                }

                // add heading
                if (!String.IsNullOrEmpty(heading))
                {
                    workSheet.Cells["A1"].Value = heading;
                    workSheet.Cells[1, dataTable.Rows.Count].Merge = true;
                    workSheet.Cells["A1"].Style.Font.Size          = 20;
                    //workSheet.InsertColumn(1, 1);
                    workSheet.InsertRow(1, 1);
                    workSheet.Column(1).Width = 5;
                }

                result = package.GetAsByteArray();
            }

            return(result);
        }