create xlsx file without third party or office using c#

Question

Riya · Answer

Thanks. Creating the xlsx file but its corrupted. Also is it possible to fill the datatable data into this excel code?

Adarsh Nigam · Answer

Creating an XLSX file in C# without using any third-party libraries or Microsoft Office Interop is possible by working with the Open XML format, which is the native format for Excel files since Excel 2007. This can be done by generating the necessary XML structure manually and then saving it as an .xlsx file. Here's a basic example of how you can do this: Steps to Create XLSX Manually in C# Create the Required XML Parts: You need to create several XML files that represent different parts of the XLSX file, such as the workbook, worksheet, and data. Package the Parts Together: The XLSX file is essentially a zip archive that contains multiple XML files and folders. You’ll need to package these XML files into a .zip file and then rename it to .xlsx . using System; using System.IO; using System.IO.Compression; using System.Text; class Program { static void Main() { // Create the necessary folders for the XLSX file structure string folderPath = "ExcelFile"; Directory.CreateDirectory(folderPath); Directory.CreateDirectory(Path.Combine(folderPath, "_rels")); Directory.CreateDirectory(Path.Combine(folderPath, "xl")); Directory.CreateDirectory(Path.Combine(folderPath, "xl", "worksheets")); // Create [Content_Types].xml string contentTypesXml = @" "; File.WriteAllText(Path.Combine(folderPath, "[Content_Types].xml"), contentTypesXml); // Create .rels file string relsXml = @" "; File.WriteAllText(Path.Combine(folderPath, "_rels", ".rels"), relsXml); // Create workbook.xml string workbookXml = @" "; File.WriteAllText(Path.Combine(folderPath, "xl", "workbook.xml"), workbookXml); // Create sheet1.xml string sheet1Xml = @" Hello World "; File.WriteAllText(Path.Combine(folderPath, "xl", "worksheets", "sheet1.xml"), sheet1Xml); // Create the zip file (XLSX file) string xlsxPath = "Output.xlsx"; if (File.Exists(xlsxPath)) { File.Delete(xlsxPath); } ZipFile.CreateFromDirectory(folderPath, xlsxPath); // Clean up temporary files Directory.Delete(folderPath, true); Console.WriteLine("XLSX file created successfully."); } } Explanation: XML Files : Each XML file represents a different part of the Excel document. [Content_Types].xml specifies the content types. .rels file manages relationships. workbook.xml defines the workbook structure, and sheet1.xml holds the data. Zip Packaging : After creating these XML files, they are zipped together to form an .xlsx file. Limitations: This method works for simple Excel files. If you need more advanced features (like formatting, multiple sheets, etc.), it is better to use libraries like OpenXML SDK or ClosedXML. This approach allows you to create a basic Excel file programmatically in C# without relying on third-party libraries or Office Interop.