private void btn_excel_Click(object sender, EventArgs e)
        {
            Random r         = new Random();
            String fileName  = @"N:\contabilidad_ef\EstadoFinancieroNaturaleza" + "-" + DateTime.Now.ToString("dd-MM-yyyy") + "-" + r.Next(1, 30) + ".xls";
            String fileName2 = @"N:\contabilidad_ef\EstadoFinancieroFuncion" + "-" + DateTime.Now.ToString("dd-MM-yyyy") + "-" + r.Next(1, 30) + ".xls";
            String fileName3 = @"N:\contabilidad_ef\EstadoFlujoEfectivo" + "-" + DateTime.Now.ToString("dd-MM-yyyy") + "-" + r.Next(1, 30) + ".xls";
            String fileName4 = @"N:\contabilidad_ef\BalanceComprobacion" + "-" + DateTime.Now.ToString("dd-MM-yyyy") + "-" + r.Next(1, 30) + ".xls";

            if (cmb_estado.SelectedValue.ToString() == "01")
            {
                objListEGPN = objAsientoDao.getEstadoGPNaturaleza(cmb_anio.SelectedValue.ToString(), cmb_Mes.SelectedValue.ToString());
                //objListEGPN.Sort(objn.Desc);

                btn_excel.Enabled = false;
                Reporte.GananciasPerdidasNaturaleza cr = new Reporte.GananciasPerdidasNaturaleza();
                cr.SetDataSource(objListEGPN);
                ExportOptions              exportOpts      = new ExportOptions();
                ExcelFormatOptions         excelFormatOpts = new ExcelFormatOptions();
                DiskFileDestinationOptions diskOpts        = new DiskFileDestinationOptions();
                exportOpts = cr.ExportOptions;

                // Set the excel format options.
                excelFormatOpts.ExcelUseConstantColumnWidth = true;
                excelFormatOpts.ExcelTabHasColumnHeadings   = true;
                excelFormatOpts.ShowGridLines = true;
                excelFormatOpts.ExportPageBreaksForEachPage = true;
                //excelFormatOpts.UsePageRange = true;

                exportOpts.ExportFormatType = ExportFormatType.Excel;
                exportOpts.FormatOptions    = excelFormatOpts;

                // Set the disk file options and export.
                exportOpts.ExportDestinationType = ExportDestinationType.DiskFile;
                diskOpts.DiskFileName            = fileName;
                exportOpts.DestinationOptions    = diskOpts;
                SaveFileDialog saveFileDialog1 = new SaveFileDialog();
                cr.Export();
                btn_excel.Enabled = true;
            }
            else if (cmb_estado.SelectedValue.ToString() == "02")
            {
                objListEGPF       = objAsientoDao.getEstadoGPFuncion(cmb_anio.SelectedValue.ToString(), cmb_Mes.SelectedValue.ToString());
                btn_excel.Enabled = false;
                Reporte.GananciasPerdidasFuncion cr = new Reporte.GananciasPerdidasFuncion();
                cr.SetDataSource(objListEGPF);
                ExportOptions              exportOpts      = new ExportOptions();
                ExcelFormatOptions         excelFormatOpts = new ExcelFormatOptions();
                DiskFileDestinationOptions diskOpts        = new DiskFileDestinationOptions();
                exportOpts = cr.ExportOptions;

                // Set the excel format options.
                excelFormatOpts.ExcelUseConstantColumnWidth = true;
                excelFormatOpts.ExcelTabHasColumnHeadings   = true;
                excelFormatOpts.ShowGridLines = true;
                excelFormatOpts.ExportPageBreaksForEachPage = true;
                //excelFormatOpts.UsePageRange = true;

                exportOpts.ExportFormatType = ExportFormatType.Excel;
                exportOpts.FormatOptions    = excelFormatOpts;

                // Set the disk file options and export.
                exportOpts.ExportDestinationType = ExportDestinationType.DiskFile;
                diskOpts.DiskFileName            = fileName2;
                exportOpts.DestinationOptions    = diskOpts;
                SaveFileDialog saveFileDialog1 = new SaveFileDialog();
                cr.Export();
                btn_excel.Enabled = true;
            }
            else if (cmb_estado.SelectedValue.ToString() == "03")
            {
                objListFE         = objAsientoDao.getEstadoFlujoEfectivo(cmb_anio.SelectedValue.ToString(), cmb_Mes.SelectedValue.ToString());
                btn_excel.Enabled = false;
                Reporte.EstadoFlujoEfectivo cr = new Reporte.EstadoFlujoEfectivo();
                cr.SetDataSource(objListFE);
                ExportOptions              exportOpts      = new ExportOptions();
                ExcelFormatOptions         excelFormatOpts = new ExcelFormatOptions();
                DiskFileDestinationOptions diskOpts        = new DiskFileDestinationOptions();
                exportOpts = cr.ExportOptions;

                // Set the excel format options.
                excelFormatOpts.ExcelUseConstantColumnWidth = true;
                excelFormatOpts.ExcelTabHasColumnHeadings   = true;
                excelFormatOpts.ShowGridLines = true;
                excelFormatOpts.ExportPageBreaksForEachPage = true;
                //excelFormatOpts.UsePageRange = true;

                exportOpts.ExportFormatType = ExportFormatType.Excel;
                exportOpts.FormatOptions    = excelFormatOpts;

                // Set the disk file options and export.
                exportOpts.ExportDestinationType = ExportDestinationType.DiskFile;
                diskOpts.DiskFileName            = fileName3;
                exportOpts.DestinationOptions    = diskOpts;
                SaveFileDialog saveFileDialog1 = new SaveFileDialog();
                cr.Export();
                btn_excel.Enabled = true;
            }
            else if (cmb_estado.SelectedValue.ToString() == "04")
            {
                //objListFE = objAsientoDao.getEstadoFlujoEfectivo(cmb_anio.SelectedValue.ToString(), cmb_Mes.SelectedValue.ToString());
                btn_excel.Enabled = false;
                Reporte.BalanceComprobacion cr = new Reporte.BalanceComprobacion();
                //cr.SetDataSource(objListFE);
                ExportOptions              exportOpts      = new ExportOptions();
                ExcelFormatOptions         excelFormatOpts = new ExcelFormatOptions();
                DiskFileDestinationOptions diskOpts        = new DiskFileDestinationOptions();
                exportOpts = cr.ExportOptions;

                // Set the excel format options.
                excelFormatOpts.ExcelUseConstantColumnWidth = true;
                excelFormatOpts.ExcelTabHasColumnHeadings   = true;
                excelFormatOpts.ShowGridLines = true;
                excelFormatOpts.ExportPageBreaksForEachPage = true;
                //excelFormatOpts.UsePageRange = true;

                exportOpts.ExportFormatType = ExportFormatType.Excel;
                exportOpts.FormatOptions    = excelFormatOpts;

                // Set the disk file options and export.
                exportOpts.ExportDestinationType = ExportDestinationType.DiskFile;
                diskOpts.DiskFileName            = fileName4;
                exportOpts.DestinationOptions    = diskOpts;
                SaveFileDialog saveFileDialog1 = new SaveFileDialog();
                cr.Export();
                btn_excel.Enabled = true;
            }
        }