C# - DocumentFormat.OpenXml

private void ExportDataSet(DataSet ds, string destination)
        {
            using (var workbook = SpreadsheetDocument.Create(destination, DocumentFormat.OpenXml.SpreadsheetDocumentType.Workbook))
            {
                var workbookPart = workbook.AddWorkbookPart();

                workbook.WorkbookPart.Workbook = new DocumentFormat.OpenXml.Spreadsheet.Workbook();

                workbook.WorkbookPart.Workbook.Sheets = new DocumentFormat.OpenXml.Spreadsheet.Sheets();

                foreach (System.Data.DataTable table in ds.Tables) {

                    var sheetPart = workbook.WorkbookPart.AddNewPart<WorksheetPart>();
                    var sheetData = new DocumentFormat.OpenXml.Spreadsheet.SheetData();
                    sheetPart.Worksheet = new DocumentFormat.OpenXml.Spreadsheet.Worksheet(sheetData);

                    DocumentFormat.OpenXml.Spreadsheet.Sheets sheets = workbook.WorkbookPart.Workbook.GetFirstChild<DocumentFormat.OpenXml.Spreadsheet.Sheets>();
                    string relationshipId = workbook.WorkbookPart.GetIdOfPart(sheetPart);

                    uint sheetId = 1;
                    if (sheets.Elements<DocumentFormat.OpenXml.Spreadsheet.Sheet>().Count() > 0)
                    {
                        sheetId =
                            sheets.Elements<DocumentFormat.OpenXml.Spreadsheet.Sheet>().Select(s => s.SheetId.Value).Max() + 1;
                    }

                    DocumentFormat.OpenXml.Spreadsheet.Sheet sheet = new DocumentFormat.OpenXml.Spreadsheet.Sheet() { Id = relationshipId, SheetId = sheetId, Name = table.TableName };
                    sheets.Append(sheet);

                    DocumentFormat.OpenXml.Spreadsheet.Row headerRow = new DocumentFormat.OpenXml.Spreadsheet.Row();

                    List<String> columns = new List<string>();
                    foreach (System.Data.DataColumn column in table.Columns) {
                        columns.Add(column.ColumnName);

                        DocumentFormat.OpenXml.Spreadsheet.Cell cell = new DocumentFormat.OpenXml.Spreadsheet.Cell();
                        cell.DataType = DocumentFormat.OpenXml.Spreadsheet.CellValues.String;
                        cell.CellValue = new DocumentFormat.OpenXml.Spreadsheet.CellValue(column.ColumnName);
                        headerRow.AppendChild(cell);
                    }


                    sheetData.AppendChild(headerRow);

                    foreach (System.Data.DataRow dsrow in table.Rows)
                    {
                        DocumentFormat.OpenXml.Spreadsheet.Row newRow = new DocumentFormat.OpenXml.Spreadsheet.Row();
                        foreach (String col in columns)
                        {
                            DocumentFormat.OpenXml.Spreadsheet.Cell cell = new DocumentFormat.OpenXml.Spreadsheet.Cell();
                            cell.DataType = DocumentFormat.OpenXml.Spreadsheet.CellValues.String;
                            cell.CellValue = new DocumentFormat.OpenXml.Spreadsheet.CellValue(dsrow[col].ToString()); //
                            newRow.AppendChild(cell);
                        }

                        sheetData.AppendChild(newRow);
                    }

                }
            }
        }

private void ExportDSToExcel(DataSet ds, string destination)
{
    using (var workbook = SpreadsheetDocument.Create(destination, DocumentFormat.OpenXml.SpreadsheetDocumentType.Workbook))
    {
        var workbookPart = workbook.AddWorkbookPart();
        workbook.WorkbookPart.Workbook = new DocumentFormat.OpenXml.Spreadsheet.Workbook();
        workbook.WorkbookPart.Workbook.Sheets = new DocumentFormat.OpenXml.Spreadsheet.Sheets();

        uint sheetId = 1;

        foreach (DataTable table in ds.Tables)
        {
            var sheetPart = workbook.WorkbookPart.AddNewPart<WorksheetPart>();
            var sheetData = new DocumentFormat.OpenXml.Spreadsheet.SheetData();
            sheetPart.Worksheet = new DocumentFormat.OpenXml.Spreadsheet.Worksheet(sheetData);                

            DocumentFormat.OpenXml.Spreadsheet.Sheets sheets = workbook.WorkbookPart.Workbook.GetFirstChild<DocumentFormat.OpenXml.Spreadsheet.Sheets>();
            string relationshipId = workbook.WorkbookPart.GetIdOfPart(sheetPart);

            if (sheets.Elements<DocumentFormat.OpenXml.Spreadsheet.Sheet>().Count() > 0)
            {
                sheetId =
                    sheets.Elements<DocumentFormat.OpenXml.Spreadsheet.Sheet>().Select(s => s.SheetId.Value).Max() + 1;
            }

            DocumentFormat.OpenXml.Spreadsheet.Sheet sheet = new DocumentFormat.OpenXml.Spreadsheet.Sheet() { Id = relationshipId, SheetId = sheetId, Name = table.TableName };
            sheets.Append(sheet);

            DocumentFormat.OpenXml.Spreadsheet.Row headerRow = new DocumentFormat.OpenXml.Spreadsheet.Row();

            List<String> columns = new List<string>();
            foreach (DataColumn column in table.Columns)
            {
                columns.Add(column.ColumnName);

                DocumentFormat.OpenXml.Spreadsheet.Cell cell = new DocumentFormat.OpenXml.Spreadsheet.Cell();
                cell.DataType = DocumentFormat.OpenXml.Spreadsheet.CellValues.String;
                cell.CellValue = new DocumentFormat.OpenXml.Spreadsheet.CellValue(column.ColumnName);
                headerRow.AppendChild(cell);
            }

            sheetData.AppendChild(headerRow);

            foreach (DataRow dsrow in table.Rows)
            {
                DocumentFormat.OpenXml.Spreadsheet.Row newRow = new DocumentFormat.OpenXml.Spreadsheet.Row();
                foreach (String col in columns)
                {
                    DocumentFormat.OpenXml.Spreadsheet.Cell cell = new DocumentFormat.OpenXml.Spreadsheet.Cell();
                    cell.DataType = DocumentFormat.OpenXml.Spreadsheet.CellValues.String;
                    cell.CellValue = new DocumentFormat.OpenXml.Spreadsheet.CellValue(dsrow[col].ToString()); //
                    newRow.AppendChild(cell);
                }

                sheetData.AppendChild(newRow);
            }
        }
    }
}

출처 : https://code.i-harness.com/ko/q/b43947