using IronXL; using System; using System.Linq; // Supported for XLSX, XLS, XLSM, XLTX, CSV and TSV WorkBook workBook = WorkBook.Load("sample.xlsx"); // Select worksheet at index 0 WorkSheet workSheet = workBook.WorkSheets[0]; // Get any existing worksheet WorkSheet firstSheet = workBook.DefaultWorkSheet; // Select a cell and return the converted value int cellValue = workSheet["A2"].IntValue; // Read from ranges of cells elegantly. foreach (var cell in workSheet["A2:A10"]) { Console.WriteLine("Cell {0} has value '{1}'", cell.AddressString, cell.Text); } // Calculate aggregate values such as Min, Max and Sum decimal sum = workSheet["A2:A10"].Sum(); // Linq compatible decimal max = workSheet["A2:A10"].Max(c => c.DecimalValue);

USING IRONXL

How to Convert XLS to XLSX File in C#

Name: IronXL
Brand: Iron Software
Availability: InStock
Rating: 4.67 (175 reviews)

Regan Pun

June 28, 2023

Updated March 31, 2024

This article will explore the IronXL library to convert XLS to XLSX format in the C# Console Application.

IronXL - An Excel Library

IronXL is a .NET Excel Library that helps developers create, read and edit Excel files in C# applications. It is fast and accurate in terms of performance and output respectively. It supports all Excel workbook file formats (XLS, XLSX, XLSM, CSV, TSV). IronXL also allows data to be saved or exported from Excel formats (XLS, XLSX) to JSON, HTML, Binary, Byte Array, DataSet, or DataTable.

IronXL allows developers to work with worksheets and cell ranges elegantly. With IronXL, you can edit formulas. Recalculation of the already given formula in the sheet is very easy to do. Data can be sorted based on range, column, or row. It provides you the facility to edit layouts like freeze panes, auto-size rows/columns, and add and remove rows/columns.

With IronXL, Excel files can be protected with a user password and permission to edit the file. Another feature is that you can add, remove and extract images from Excel worksheets. It also provides a wide range of Excel functions with almost all cell data formats. This makes IronXL one of the most intuitive APIs when it comes to working with Excel files.

IronXL does not need Microsoft Excel to be installed on the machine as it does not require Office Interop or any other dependency. It works on multiple platforms and is compatible with .NET 7, 6 & 5. It also supports .NET Core 2 and 3 along with the standard 2 versions. .NET Framework 4.5 and onwards is also supported for working Excel spreadsheets.

Create a Console Application

The Visual Studio latest version is recommended for creating an application to start with. Visual Studio is the official IDE for C# development, and you must have installed it. You can download it from the Microsoft Visual Studio website, if not installed.

The following steps will create a new project named "DemoApp".

Open Visual Studio and click on Create a New Project
Open Visual Studio
Select Console Application and Click Next
Create a new project in Visual Studio
Set the name of the Project
Configure your new project
Select the .NET version. Choose the stable version .NET 6.0.
.NET Framework selection

Install IronXL Library

Once the project is created, the IronXL library needs to be installed in the project to use it. Follow the steps to install it.

Open Manage NuGet Packages for Solutions either from Solution Explorer or Tools.
Navigate to NuGet Package Manager
Browse for IronXL Library and Select the current project. Click install.
Search and install the IronXL package in NuGet Package Manager UI

Add the following namespace at the top of the Program.cs file

using IronXL;

using IronXL;

Imports IronXL

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Open an Existing XLS file

IronXL provides the facility to open an existing Excel file, or you can create a new Excel file. Here we are going to open an existing Excel XLS file using the C# IronXL LoadExcel method. The Load method is a short synonym for LoadExcel.

// Supported spreadsheet formats for reading XLSX, XLS, XLSM, XLTX, CSV and TSV
WorkBook workBook = WorkBook.LoadExcel("sample.xls");

// Supported spreadsheet formats for reading XLSX, XLS, XLSM, XLTX, CSV and TSV
WorkBook workBook = WorkBook.LoadExcel("sample.xls");

' Supported spreadsheet formats for reading XLSX, XLS, XLSM, XLTX, CSV and TSV
Dim workBook As WorkBook = WorkBook.LoadExcel("sample.xls")

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The sample file loaded is as follows:

How to Convert XLS to XLSX File in C#, Figure 7: A sample XLS data file A sample XLS data file

To create Excel files in XLS or XLSX format you can visit this code examples page here.

Convert XLS File to XLSX File

To convert XLS to an XLSX file, IronXL just uses the Save method to do this conversion. The following code shows how to save an XLS file to an XLSX file:

workBook.SaveAs("converted_sample.xlsx");

workBook.SaveAs("converted_sample.xlsx");

workBook.SaveAs("converted_sample.xlsx")

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That's it. We have successfully converted XLS to XLSX format. To convert to other formats you can visit this code examples page.

Output

How to Convert XLS to XLSX File in C#, Figure 8: The exported XLSX file The exported XLSX file

You can see that the data is the same even after conversion. IronXL provides ease-of-use, speed, and accuracy.

Summary

This article demonstrated how to convert XLS Excel files to XLSX files using IronXL in C#. IronXL provides the facility to work with existing Excel files without any hassle. Conversion between different spreadsheet formats is usually a one-line process. It's fast, easy to use, and accurate. It also allows you to create new Excel files and write data to it with easy syntax. IronXL can also be used to read Excel files without Microsoft Office installed. To read data from Excel files you can see this code example page.

IronXL is free for development and can be licensed for commercial use. You can also try IronXL for a free trial for commercial use. Download the software from the IronXL website.

Regan Pun

Chat with engineering team now

Software Engineer

Regan graduated from the University of Reading, with a BA in Electronic Engineering. Before joining Iron Software, his previous job roles had him laser-focused on single tasks; and what he most enjoys at Iron Software is the spectrum of work he gets to undertake, whether it’s adding value to sales, technical support, product development or marketing. He enjoys understanding the way developers are using the Iron Software library, and using that knowledge to continually improve documentation and develop the products.

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