CSharp: Convert CSV to XLS Using Open XML SDK

using System;
using System.Data;
using System.IO;
using System.Linq;
using System.Text;
using System.Globalization;
using CsvHelper;
using DocumentFormat.OpenXml;
using DocumentFormat.OpenXml.Packaging;
using DocumentFormat.OpenXml.Spreadsheet;namespace CsvToXlsConverter
{class Program{static void Main(string[] args){try{// Parse command line argumentsstring inputPath = null;string outputPath = null;Encoding encoding = Encoding.UTF8;char delimiter = ',';for (int i = 0; i < args.Length; i++){switch (args[i].ToLower()){case "-i":case "--input":if (i + 1 < args.Length)inputPath = args[++i];break;case "-o":case "--output":if (i + 1 < args.Length)outputPath = args[++i];break;case "-e":case "--encoding":if (i + 1 < args.Length){string encodingName = args[++i];try{encoding = Encoding.GetEncoding(encodingName);}catch{Console.WriteLine($"Warning: Unsupported encoding '{encodingName}'. Using default UTF-8.");}}break;case "-d":case "--delimiter":if (i + 1 < args.Length){string delimiterStr = args[++i];if (delimiterStr.Length == 1)delimiter = delimiterStr[0];else if (delimiterStr.Equals("tab", StringComparison.OrdinalIgnoreCase))delimiter = '\t';elseConsole.WriteLine($"Warning: Unsupported delimiter '{delimiterStr}'. Using default comma.");}break;case "-h":case "--help":ShowHelp();return;}}// Validate input and output pathsif (string.IsNullOrEmpty(inputPath))throw new ArgumentException("Input file path is required. Use -i or --input option.");if (string.IsNullOrEmpty(outputPath))outputPath = Path.ChangeExtension(inputPath, ".xls");if (!File.Exists(inputPath))throw new FileNotFoundException("Input file not found.", inputPath);// Check if output directory existsstring outputDirectory = Path.GetDirectoryName(outputPath);if (!string.IsNullOrEmpty(outputDirectory) && !Directory.Exists(outputDirectory))Directory.CreateDirectory(outputDirectory);// Convert CSV to XLSConsole.WriteLine("CSV to XLS Converter");Console.WriteLine("====================");Console.WriteLine($"Input file: {inputPath}");Console.WriteLine($"Output file: {outputPath}");Console.WriteLine($"Encoding: {encoding.EncodingName}");Console.WriteLine($"Delimiter: {(delimiter == '\t' ? "Tab" : delimiter.ToString())}");Console.WriteLine();DateTime startTime = DateTime.Now;try{// Read CSVConsole.WriteLine("Reading CSV file...");DataTable dataTable = ReadCsv(inputPath, encoding, delimiter);Console.WriteLine($"Successfully read {dataTable.Rows.Count} rows and {dataTable.Columns.Count} columns.");// Convert to XLSConsole.WriteLine("Converting to XLS format...");ConvertDataTableToXls(dataTable, outputPath);TimeSpan duration = DateTime.Now - startTime;Console.WriteLine();Console.WriteLine($"Conversion completed successfully in {duration.TotalSeconds:F2} seconds.");Console.WriteLine($"Output file saved to: {outputPath}");}catch (Exception ex){Console.WriteLine();throw new Exception($"Conversion failed: {ex.Message}", ex);}}catch (Exception ex){Console.WriteLine($"Error: {ex.Message}");Console.WriteLine();Console.WriteLine("Use --help for usage information.");}}/// <summary>/// Reads a CSV file and returns its contents as a DataTable/// </summary>public static DataTable ReadCsv(string filePath, Encoding encoding, char delimiter){try{using (var reader = new StreamReader(filePath, encoding))using (var csv = new CsvReader(reader, new CsvHelper.Configuration.CsvConfiguration(CultureInfo.InvariantCulture){Delimiter = delimiter.ToString(),HasHeaderRecord = true,IgnoreBlankLines = true,TrimOptions = CsvHelper.Configuration.TrimOptions.Trim})){using (var dr = new CsvDataReader(csv)){var dt = new DataTable();dt.Load(dr);return dt;}}}catch (Exception ex){throw new Exception($"Failed to read CSV file: {ex.Message}", ex);}}/// <summary>/// Converts a DataTable to an XLS file using Open XML SDK/// </summary>public static void ConvertDataTableToXls(DataTable dataTable, string outputPath){try{// Create a new spreadsheet documentusing (SpreadsheetDocument document = SpreadsheetDocument.Create(outputPath, SpreadsheetDocumentType.Workbook)){// Add a WorkbookPart to the documentWorkbookPart workbookPart = document.AddWorkbookPart();workbookPart.Workbook = new Workbook();// Add a WorksheetPart to the WorkbookPartWorksheetPart worksheetPart = workbookPart.AddNewPart<WorksheetPart>();worksheetPart.Worksheet = new Worksheet(new SheetData());// Add Sheets to the WorkbookSheets sheets = workbookPart.Workbook.AppendChild(new Sheets());// Append a new worksheet and associate it with the workbookSheet sheet = new Sheet(){Id = workbookPart.GetIdOfPart(worksheetPart),SheetId = 1,Name = "Sheet1"};sheets.Append(sheet);// Get the SheetData objectSheetData sheetData = worksheetPart.Worksheet.GetFirstChild<SheetData>();// Add header rowRow headerRow = new Row();foreach (DataColumn column in dataTable.Columns){Cell cell = CreateCell(column.ColumnName, CellValues.String);headerRow.AppendChild(cell);}sheetData.AppendChild(headerRow);// Add data rowsforeach (DataRow row in dataTable.Rows){Row dataRow = new Row();foreach (var item in row.ItemArray){CellValues cellType = GetCellValueType(item);string cellValue = GetCellValueAsString(item, cellType);Cell cell = CreateCell(cellValue, cellType);dataRow.AppendChild(cell);}sheetData.AppendChild(dataRow);}// Save the workbookworkbookPart.Workbook.Save();}}catch (Exception ex){throw new Exception($"Failed to create XLS file: {ex.Message}", ex);}}/// <summary>/// Creates a new Excel cell with the specified value and type/// </summary>private static Cell CreateCell(string value, CellValues cellType){Cell cell = new Cell();cell.DataType = new EnumValue<CellValues>(cellType);cell.CellValue = new CellValue(value);return cell;}/// <summary>/// Determines the cell value type based on the object type/// </summary>private static CellValues GetCellValueType(object value){if (value == DBNull.Value)return CellValues.String;Type type = value.GetType();if (type == typeof(int) || type == typeof(long) || type == typeof(short) || type == typeof(byte))return CellValues.Number;else if (type == typeof(float) || type == typeof(double) || type == typeof(decimal))return CellValues.Number;else if (type == typeof(DateTime))return CellValues.Date;else if (type == typeof(bool))return CellValues.Boolean;elsereturn CellValues.String;}/// <summary>/// Converts an object to its string representation based on the cell type/// </summary>private static string GetCellValueAsString(object value, CellValues cellType){if (value == DBNull.Value)return string.Empty;switch (cellType){case CellValues.Boolean:return (bool)value ? "1" : "0";case CellValues.Date:DateTime dateValue = (DateTime)value;// Excel stores dates as OLE Automation datesreturn dateValue.ToOADate().ToString(CultureInfo.InvariantCulture);case CellValues.Number:return Convert.ToString(value, CultureInfo.InvariantCulture);default:return Convert.ToString(value);}}/// <summary>/// Shows help information/// </summary>private static void ShowHelp(){Console.WriteLine("CSV to XLS Converter");Console.WriteLine("Converts CSV files to XLS (Excel 97-2003) format using Open XML SDK.");Console.WriteLine();Console.WriteLine("Usage: CsvToXlsConverter [options]");Console.WriteLine();Console.WriteLine("Options:");Console.WriteLine("  -i, --input      Input CSV file path (required)");Console.WriteLine("  -o, --output     Output XLS file path (optional, defaults to input path with .xls extension)");Console.WriteLine("  -e, --encoding   Encoding of the CSV file (optional, defaults to UTF-8)");Console.WriteLine("                   Examples: UTF-8, ASCII, Windows-1252, etc.");Console.WriteLine("  -d, --delimiter  Field delimiter character (optional, defaults to comma)");Console.WriteLine("                   Use 'tab' for tab-delimited files");Console.WriteLine("  -h, --help       Show this help message");Console.WriteLine();Console.WriteLine("Examples:");Console.WriteLine("  CsvToXlsConverter -i data.csv");Console.WriteLine("  CsvToXlsConverter -i input.csv -o output.xls");Console.WriteLine("  CsvToXlsConverter -i data.tsv -d tab -e Windows-1252");}}
}