Installation

dotnet-poi ships as multiple NuGet packages — pick the combination that fits your project.

Quick Pick

If you need…	Install this
xlsx / docx / pptx read/write only	`DotnetPoi.Ooxml`
OOXML + formula evaluator	`DotnetPoi.Ooxml` + `DotnetPoi.Formula`
xls / doc / ppt (legacy binary) only	`DotnetPoi.Legacy`
All formats + formula (everything)	`DotnetPoi.All`

Package Reference

OOXML-only project (xlsx, docx, pptx):

<ItemGroup>
  <PackageReference Include="DotnetPoi.Ooxml" Version="..." />
</ItemGroup>

Add formula evaluation when needed:

<ItemGroup>
  <PackageReference Include="DotnetPoi.Ooxml" Version="..." />
  <PackageReference Include="DotnetPoi.Formula" Version="..." />
</ItemGroup>

Legacy binary formats (xls, doc, ppt):

<ItemGroup>
  <PackageReference Include="DotnetPoi.Legacy" Version="..." />
</ItemGroup>

Everything in one dependency:

<ItemGroup>
  <PackageReference Include="DotnetPoi.All" Version="..." />
</ItemGroup>

Transitive dependencies (DotnetPoi.Common, DotnetPoi.POIFS) are resolved automatically by NuGet.

Why Multiple Packages?

Package	Contents	Best for
`DotnetPoi.Ooxml`	XSSF (xlsx/xlsm), XWPF (docx/docm), XSLF (pptx/pptm)	Modern Office 2007+ formats
`DotnetPoi.Legacy`	HSSF (xls), HWPF (doc), HSLF (ppt)	Legacy binary formats
`DotnetPoi.Formula`	Formula evaluator (`IFormulaEvaluator`, `FormulaEvaluator`, `CellValue`)	Programmatic formula calculation
`DotnetPoi.Common`	SS interfaces, shared enums, XML writer	Included transitively
`DotnetPoi.POIFS`	OLE2/CFB container, encryption helpers	Included transitively
`DotnetPoi.All`	All of the above in one meta-package	Convenience

Design principle: Format packages have zero knowledge of Formula. Adding DotnetPoi.Formula to your project automatically enables createFormulaEvaluator() via lazy assembly discovery at runtime. Without it, the call throws a clear NotSupportedException.

Verify Installation

Create a file TestInstall.csproj:

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net8.0</TargetFramework>
  </PropertyGroup>
  <ItemGroup>
    <PackageReference Include="DotnetPoi.Ooxml" Version="..." />
  </ItemGroup>
</Project>

Add Program.cs:

using DotnetPoi.XSSF.UserModel;

using var wb = new XSSFWorkbook();
var sheet = wb.createSheet("Test");
var row = sheet.createRow(0);
row.createCell(0).setCellValue("Hello, dotnet-poi!");

using var file = File.Create("test.xlsx");
wb.write(file);

Console.WriteLine("test.xlsx created successfully.");

Run:

dotnet run

Open test.xlsx in Excel or LibreOffice to confirm the content.

Package Split Details

See the Package Split page for the full design rationale.