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Raphael Stoeckli edited this page Mar 5, 2026 · 5 revisions

Welcome to the NanoXLSX wiki!

Introduction

NanoXLSX is a small .NET library written in C#, to create and read Microsoft Excel files in the XLSX format (Microsoft Excel 2007 or newer) in an easy and native way

  • ✅ Minimum of dependencies (*
  • ❌ No need for an installation of Microsoft Office
  • ❌ No need for Office interop libraries
  • ❌ No need for proprietary 3rd party libraries
  • ❌ No need for an installation of the Microsoft Open Office XML SDK (OOXML)

📄 See the Change Log for recent updates.

Modules

NanoXLSX v3 is split into modular NuGet packages:

Module Status Description
NanoXLSX.Core 🟢 Mandatory, Bundled Core library with workbooks, worksheets, cells, styles. No external dependencies
NanoXLSX.Reader 🔵 Optional, Bundled Extension methods to read/load XLSX files. Depends on Core
NanoXLSX.Writer 🔵 Optional, Bundled Extension methods to write/save XLSX files. Depends on Core
NanoXLSX.Formatting 🔵 Optional, Bundled In-line cell formatting (rich text). External repo. Depends on Core
NanoXLSX ⭐ Meta-Package Bundles all of the above. Recommended for most users

Note: All bundled modules are included when you install the NanoXLSX meta-package. There are currently no non-bundled (standalone) modules.

For advanced scenarios, you can install only the specific packages you need (e.g. NanoXLSX.Core + NanoXLSX.Writer for write-only applications).

Requirements

NanoXLSX is originally based on PicoXLSX. However, NanoXLSX is now in the development lead, whereas PicoXLSX is a subset of it. The library is currently on compatibility level with .NET version 4.5 and .NET Standard 2.0. Newer versions should of course work as well. Older versions, like .NET 3.5 have only limited support, since newer language features were used.

.NET 4.5 or newer

*)The only requirement to compile the library besides .NET (v4.5 or newer) is the assembly WindowsBase, as well as System.IO.Compression. These assemblies are standard components in all Microsoft Windows systems (except Windows RT systems). If your IDE of choice supports referencing assemblies from the Global Assembly Cache (GAC) of Windows, select WindowsBase and Compression from there. If you want so select the DLLs manually and Microsoft Visual Studio is installed on your system, the DLL of WindowsBase can be found most likely under "c:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0\WindowsBase.dll", as well as System.IO.Compression under "c:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.5\System.IO.Compression.dll". Otherwise you find them in the GAC, under "c:\Windows\Microsoft.NET\assembly\GAC_MSIL\WindowsBase" and "c:\Windows\Microsoft.NET\assembly\GAC_MSIL\System.IO.Compression"

The NuGet package does not require dependencies

.NET Standard

.NET Standard v2.0 resolves the dependency System.IO.Compression automatically, using NuGet and does not rely anymore on WindowsBase in the development environment. In contrast to the .NET >=4.5 version, no manually added dependencies necessary (as assembly references) to compile the library.

Utility dependencies

The Test project and GitHub Actions may also require dependencies like unit testing frameworks or workflow steps. However, none of these dependencies are essential to build the library. They are just utilities. The test dependencies ensure efficient unit testing and code coverage. The GitHub Actions dependencies are used for the automatization of releases and API documentation

*)The only requirement to compile the library besides .NET is the assembly WindowsBase, as well as System.IO.Compression. These assemblies are standard components in all Microsoft Windows systems (except Windows RT systems). If your IDE of choice supports referencing assemblies from the Global Assembly Cache (GAC) of Windows, select WindowsBase and Compression from there. If you want so select the DLLs manually and Microsoft Visual Studio is installed on your system, the DLL of WindowsBase can be found most likely under “c:\Program Files\Reference Assemblies\Microsoft\Framework\v3.0\WindowsBase.dll”, as well as System.IO.Compression under "c:\Program Files (x86)\Reference Assemblies\Microsoft\Framework.NETFramework\v4.5\System.IO.Compression.dll". Otherwise you find them in the GAC, under “c:\Windows\Microsoft.NET\assembly\GAC_MSIL\WindowsBase” and "c:\Windows\Microsoft.NET\assembly\GAC_MSIL\System.IO.Compression"

If you want to compile the documentation project (folder: Documentation; project file: shfbproj), you need also the Sandcastle Help File Builder (SHFB). It is also freely available. But you don't need the documentation project to build the NanoXLSX library.

Installation

Using NuGet (recommended)

By package Manager (PM):

Install-Package NanoXLSX

By .NET CLI:

dotnet add package NanoXLSX

ℹ️ Note: Other methods like adding DLLs or source files directly into your project are technically still possible, but not recommended anymore. Use dependency management, whenever possible

Usage

Quick Start (shortened syntax)

 Workbook workbook = new Workbook("myWorkbook.xlsx", "Sheet1");         // Create new workbook with a worksheet called Sheet1
 workbook.WS.Value("Some Data");                                        // Add cell A1
 workbook.WS.Formula("=A1");                                            // Add formula to cell B1
 workbook.WS.Down();                                                    // Go to row 2
 workbook.WS.Value(DateTime.Now, Style.BasicStyles.Bold);               // Add formatted value to cell A2
 workbook.Save();                                                       // Save the workbook as myWorkbook.xlsx

Quick Start (regular syntax)

 Workbook workbook = new Workbook("myWorkbook.xlsx", "Sheet1");         // Create new workbook with a worksheet called Sheet1
 workbook.CurrentWorksheet.AddNextCell("Some Data");                    // Add cell A1
 workbook.CurrentWorksheet.AddNextCell(42);                             // Add cell B1
 workbook.CurrentWorksheet.GoToNextRow();                               // Go to row 2
 workbook.CurrentWorksheet.AddNextCell(DateTime.Now);                   // Add cell A2
 workbook.Save();                                                       // Save the workbook as myWorkbook.xlsx

Quick Start (read)

 using NanoXLSX.Extensions;

 Workbook wb = WorkbookReader.Load("basic.xlsx");                       // Read the workbook
 System.Console.WriteLine("contains worksheet name: " + wb.CurrentWorksheet.SheetName);
 foreach (KeyValuePair<string, Cell> cell in wb.CurrentWorksheet.Cells)
 {
    System.Console.WriteLine("Cell address: " + cell.Key + ": content:'" + cell.Value.Value + "'");
 }
## Further References

See the full **API-Documentation** at: [https://rabanti-github.github.io/NanoXLSX/](https://rabanti-github.github.io/NanoXLSX/).

The **[Demo Project](https://github.com/rabanti-github/NanoXLSX.Demo)** contains 27 examples covering various use cases. The demo project is maintained in a separate repository.
See the section **[NanoXLSX](https://github.com/rabanti-github/NanoXLSX.Demo/tree/main/NanoXLSX)** for the specific examples related to NanoXLSX.

See also: [Getting started in the Wiki](https://github.com/rabanti-github/NanoXLSX/wiki/Getting-started)

Hint: You will find most certainly any function, and the way how to use it, in the [Unit Test Project](https://github.com/rabanti-github/NanoXLSX/tree/master/NanoXlsx%20Test)

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