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C# Export to Excel: Complete Developer Guide

Jacob Mellor

Updated:August 20, 2025

Working with Excel data often requires exporting spreadsheets to different formats for integration with various systems and applications. This guide demonstrates how to export Excel files to multiple formats including .xlsx, .xls, .csv, .xml, and .json using C# and IronXL—without requiring Microsoft Office Interop dependencies.

Step 1

How to Install IronXL for Excel Export?

IronXL provides a streamlined approach to working with Excel files in .NET applications. Download the IronXL DLL directly or install via NuGet for development and testing.

Install-Package IronXL.Excel

After installation, add the IronXL reference to access all Excel manipulation features through the IronXL namespace. The library supports .NET Framework, .NET Core, and .NET 5+ applications, making it compatible with modern development environments.

How to Tutorial

What Excel Export Formats Does C# Support?

IronXL enables seamless data export from Excel workbooks to multiple file formats. The library supports exporting to:

• Excel formats: .xlsx (modern) and .xls (legacy)
• Data interchange formats: .csv, .json, and .xml
• Tab-separated values: .tsv

Each format serves specific use cases—CSV for database imports, JSON for web APIs, and XML for enterprise system integration. We can also export the file formats metioned above to their respective output streams to intergrate with other applications. Let's explore how to implement each export type.

How to Export Excel to XLSX in C#?

Converting between Excel formats is straightforward with IronXL. The following example demonstrates loading an older .xls file and saving it as a modern .xlsx file:

:path=/static-assets/excel/content-code-examples/how-to/c-sharp-export-to-excel-xlsx.cs

using IronXL;

// Import .xls, .csv, or .tsv file
WorkBook workbook = WorkBook.Load("XlsFile.xls");

// Export as .xlsx file
workbook.SaveAs("newFile.xlsx");

Imports IronXL

' Import .xls, .csv, or .tsv file
Private workbook As WorkBook = WorkBook.Load("XlsFile.xls")

' Export as .xlsx file
workbook.SaveAs("newFile.xlsx")

The SaveAs method automatically detects the desired format based on the file extension. When converting from .xls to .xlsx, the process preserves all worksheets, formulas, formatting, and data types. This conversion is particularly useful when modernizing legacy Excel files for compatibility with newer Office versions.

Export to XLSX Stream

Alternatively, you can also use ToXlsxStream to export the document to an XLSX to integrate with other applications. Here's a brief example on how to do it.

:path=/static-assets/excel/content-code-examples/how-to/c-sharp-export-to-excel-xlsx-stream.cs

using IronXL;

// Load the workbook
WorkBook workbook = WorkBook.Load("xlsFile.xlsx");

// Exports the workbook to a XLSX stream.
var stream = workbook.ToXlsxStream();

Imports IronXL

' Load the workbook
Private workbook As WorkBook = WorkBook.Load("xlsFile.xlsx")

' Exports the workbook to a XLSX stream.
Private stream = workbook.ToXlsxStream()

How to Export Excel to XLS Format?

Legacy systems sometimes require the older .xls format. IronXL handles this conversion seamlessly:

:path=/static-assets/excel/content-code-examples/how-to/c-sharp-export-to-excel-xls.cs

using IronXL;

// Import .xlsx, .csv or .tsv file
WorkBook workbook = WorkBook.Load("XlsxFile.xlsx");

// Export as .xls file
workbook.SaveAs("newFile.xls");

Imports IronXL

' Import .xlsx, .csv or .tsv file
Private workbook As WorkBook = WorkBook.Load("XlsxFile.xlsx")

' Export as .xls file
workbook.SaveAs("newFile.xls")

This conversion maintains compatibility with Excel 97-2003 versions. The SaveAs method handles the format conversion internally, ensuring data integrity while adapting to the .xls format limitations such as the 65,536 row limit per worksheet.

Export to XLS Stream

In addition to using SaveAs to export to the legacy .XLS format, IronXL also supports exporting as an XLS stream.

:path=/static-assets/excel/content-code-examples/how-to/c-sharp-export-to-excel-xls-stream.cs

using IronXL;

// Load the workbook
WorkBook workbook = WorkBook.Load("xlsxFile.xlsx");

// Exports the workbook to a XLS stream.
workbook.ToXlsStream();

Imports IronXL

' Load the workbook
Private workbook As WorkBook = WorkBook.Load("xlsxFile.xlsx")

' Exports the workbook to a XLS stream.
workbook.ToXlsStream()

How to Convert Excel to CSV in C#?

CSV export is essential for data exchange between different systems. IronXL provides a dedicated method for CSV conversion:

:path=/static-assets/excel/content-code-examples/how-to/c-sharp-export-to-excel-csv.cs

using IronXL;

//  Import .xlsx or xls file
WorkBook workbook = WorkBook.Load("sample.xlsx");

// Export as .xls file
workbook.SaveAsCsv("newFile.csv");

Imports IronXL

'  Import .xlsx or xls file
Private workbook As WorkBook = WorkBook.Load("sample.xlsx")

' Export as .xls file
workbook.SaveAsCsv("newFile.csv")

When exporting multi-sheet workbooks, IronXL creates separate CSV files for each worksheet. For a workbook with three sheets named "Sheet1", "Sheet2", and "Sheet3", the export generates:

Multiple CSV files generated from a three-sheet Excel workbook, with each worksheet exported as a separate CSV file

The original Excel file structure with three worksheets:

Original Excel workbook displaying three worksheets that will be exported as individual CSV files

The SaveAsCsv method preserves data values while removing formatting, formulas, and other Excel-specific features. This makes CSV ideal for importing data into databases or processing with other applications.

Export Excel Worksheet to CSV Stream

To convert only a specified worksheet within the workbook to a CSV stream, we can use the ToCsvStream method and provide an integer indicating the worksheet's index to return as a CSV stream. Below is an example of this method.

:path=/static-assets/excel/content-code-examples/how-to/c-sharp-export-to-excel-csv-stream.cs

using IronXL;

// Load the workbook
WorkBook workbook = WorkBook.Load("sample.xlsx");

// Exports the first sheet of the workbook to a CSV stream
var stream = workbook.ToCsvStream(0);

Imports IronXL

' Load the workbook
Private workbook As WorkBook = WorkBook.Load("sample.xlsx")

' Exports the first sheet of the workbook to a CSV stream
Private stream = workbook.ToCsvStream(0)

Export All to CSV Stream

IronXL also supports converting the entire workbook into a CSV stream; we use the method ToCsvStreams instead to convert all worksheets in the workbook.

:path=/static-assets/excel/content-code-examples/how-to/c-sharp-export-to-excel-csv-streams.cs

using IronXL;

// Load the workbook
WorkBook workbook = WorkBook.Load("sample.xlsx");

// Exports the entire workbook to a CSV stream
var workBookStream = workbook.ToCsvStreams();

Imports IronXL

' Load the workbook
Private workbook As WorkBook = WorkBook.Load("sample.xlsx")

' Exports the entire workbook to a CSV stream
Private workBookStream = workbook.ToCsvStreams()

How to Export Excel Data to XML?

XML export enables structured data exchange with enterprise systems. IronXL simplifies this process:

:path=/static-assets/excel/content-code-examples/how-to/c-sharp-export-to-excel-xml.cs

using IronXL;

// Import .xlsx, .xls or .csv file
WorkBook workbook = WorkBook.Load("sample.xlsx");

// Export as .xml file
workbook.SaveAsXml("newFile.xml");

Imports IronXL

' Import .xlsx, .xls or .csv file
Private workbook As WorkBook = WorkBook.Load("sample.xlsx")

' Export as .xml file
workbook.SaveAsXml("newFile.xml")

The SaveAsXml method converts each worksheet into a separate XML file with a structured representation of the spreadsheet data. This includes:

• Cell values and data types
• Row and column positioning
• Basic structural information

XML export is particularly valuable for integrating Excel data with web services or systems that require structured data formats.

Export Data as XML Stream

To export a specified worksheet to an XML stream, we use the ToXmlStream method and provide an integer parameter, which represents the index of the worksheet.

:path=/static-assets/excel/content-code-examples/how-to/c-sharp-export-to-excel-xml-stream.cs

using IronXL;

// Load the workbook
WorkBook workbook = WorkBook.Load("sample.xlsx");

// Converts the first worksheet to a XML Stream
var stream = workbook.ToXmlStream(0);

Imports IronXL

' Load the workbook
Private workbook As WorkBook = WorkBook.Load("sample.xlsx")

' Converts the first worksheet to a XML Stream
Private stream = workbook.ToXmlStream(0)

Export All Data to XML Streams

To export the entire workbook as XML streams, we use the ToXmlStreams method.

:path=/static-assets/excel/content-code-examples/how-to/c-sharp-export-to-excel-xml-streams.cs

using IronXL;

// Load the workbook
WorkBook workbook = WorkBook.Load("sample.xlsx");

// Exports the entire workbook to a XML stream
var workBookStream = workbook.ToXmlStreams();

Imports IronXL

' Load the workbook
Private workbook As WorkBook = WorkBook.Load("sample.xlsx")

' Exports the entire workbook to a XML stream
Private workBookStream = workbook.ToXmlStreams()

How to Generate JSON from Excel Files?

Modern web applications often require JSON format for data exchange. IronXL provides direct JSON export functionality:

:path=/static-assets/excel/content-code-examples/how-to/c-sharp-export-to-excel-json.cs

using IronXL;

// Import Excel file
WorkBook workbook = WorkBook.Load("sample.xlsx");

// Export as JSON file
workbook.SaveAsJson("newFile.json");

Imports IronXL

' Import Excel file
Private workbook As WorkBook = WorkBook.Load("sample.xlsx")

' Export as JSON file
workbook.SaveAsJson("newFile.json")

The SaveAsJson method creates JSON files with array-based structures representing spreadsheet data. Each worksheet exports as a separate JSON file, making it easy to:

• Integrate with RESTful APIs
• Process data in JavaScript applications
• Store spreadsheet data in NoSQL databases

For advanced scenarios, developers can combine JSON export with IronXL's data manipulation features to transform data before exporting.

Export Excel Worksheet as JSON Stream

To convert a specified worksheet to a JSON stream, we use the method ToJsonStream and provide an integer as an index of the worksheet you wish to convert.

:path=/static-assets/excel/content-code-examples/how-to/c-sharp-export-to-excel-json-stream.cs

using IronXL;

// Load the workbook
WorkBook workbook = WorkBook.Load("sample.xlsx");

// Exports the first sheet of the workbook to a JSON stream
var stream = workbook.ToJsonStream(0);

Imports IronXL

' Load the workbook
Private workbook As WorkBook = WorkBook.Load("sample.xlsx")

' Exports the first sheet of the workbook to a JSON stream
Private stream = workbook.ToJsonStream(0)

Export All as JSON Streams

To convert the entire workbook to a JSON stream, we use the method ToJsonStreams instead.

:path=/static-assets/excel/content-code-examples/how-to/c-sharp-export-to-excel-json-streams.cs

using IronXL;

// Load the workbook
WorkBook workbook = WorkBook.Load("sample.xlsx");

// Exports the entire workbook to a JSON stream
var workBookStream = workbook.ToJsonStreams();

Imports IronXL

' Load the workbook
Private workbook As WorkBook = WorkBook.Load("sample.xlsx")

' Exports the entire workbook to a JSON stream
Private workBookStream = workbook.ToJsonStreams()

Tutorial Quick Access

API Reference Documentation

Explore the complete IronXL API including all namespaces, classes, methods, and properties for advanced Excel manipulation.

View API Reference

Ready to Export Excel Files?

IronXL simplifies Excel file export operations in C# applications. Whether converting between Excel formats or exporting to data interchange formats like CSV, JSON, or XML, the library provides intuitive methods that handle complex conversions automatically.

Start implementing Excel export functionality today with a free trial of IronXL. For production deployments, explore our flexible licensing options designed for teams of all sizes.

Get stated with IronXL now.

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Jacob Mellor

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Chief Technology Officer

Jacob Mellor is Chief Technology Officer at Iron Software and a visionary engineer pioneering C# PDF technology. As the original developer behind Iron Software's core codebase, he has shaped the company's product architecture since its inception, transforming it alongside CEO Cameron Rimington into a 50+ person company serving NASA, Tesla, and global government agencies.

Jacob holds a First-Class Honours Bachelor of Engineering (BEng) in Civil Engineering from the University of Manchester (1998–2001). After opening his first software business in London in 1999 and creating his first .NET components in 2005, he specialized in solving complex problems across the Microsoft ecosystem.

His flagship IronPDF & IronSuite .NET libraries have achieved over 30 million NuGet installations globally, with his foundational code continuing to power developer tools used worldwide. With 25 years of commercial experience and 41 years of coding expertise, Jacob remains focused on driving innovation in enterprise-grade C#, Java, and Python PDF technologies while mentoring the next generation of technical leaders.

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