Create a NuGet package using MSBuild

When you create a NuGet package from your code, you package that functionality into a component that can be shared with and used by any number of other developers. This article describes how to create a package using MSBuild. MSBuild comes preinstalled with every Visual Studio workload that contains NuGet. Additionally you can also use MSBuild through the dotnet CLI with dotnet msbuild

For .NET Core and .NET Standard projects that use the SDK-style format, and any other SDK-style projects, NuGet uses information in the project file directly to create a package. For a non-SDK-style project that uses <PackageReference>, NuGet also uses the project file to create a package.

SDK-style projects have the pack functionality available by default. For non SDK-style PackageReference projects, you need to add the NuGet.Build.Tasks.Pack package to the project dependencies. For detailed information about MSBuild pack targets, see NuGet pack and restore as MSBuild targets.

The command that creates a package, msbuild -t:pack, is functionality equivalent to dotnet pack.

Important

This topic applies to SDK-style projects, typically .NET Core and .NET Standard projects, and to non-SDK-style projects that use PackageReference.

Set properties

The following properties are required to create a package.

  • PackageId, the package identifier, which must be unique across the gallery that hosts the package. If not specified, the default value is AssemblyName.
  • Version, a specific version number in the form Major.Minor.Patch[-Suffix] where -Suffix identifies pre-release versions. If not specified, the default value is 1.0.0.
  • The package title as it should appear on the host (like nuget.org)
  • Authors, author and owner information. If not specified, the default value is AssemblyName.
  • Company, your company name. If not specified, the default value is AssemblyName.

In Visual Studio, you can set these values in the project properties (right-click the project in Solution Explorer, choose Properties, and select the Package tab). You can also set these properties directly in the project files (.csproj).

<PropertyGroup>
  <PackageId>ClassLibDotNetStandard</PackageId>
  <Version>1.0.0</Version>
  <Authors>your_name</Authors>
  <Company>your_company</Company>
</PropertyGroup>

Important

Give the package an identifier that's unique across nuget.org or whatever package source you're using.

The following example shows a simple, complete project file with these properties included.

<Project Sdk="Microsoft.NET.Sdk">
  <PropertyGroup>
    <TargetFramework>netstandard2.0</TargetFramework>
    <PackageId>ClassLibDotNetStandard</PackageId>
    <Version>1.0.0</Version>
    <Authors>your_name</Authors>
    <Company>your_company</Company>
  </PropertyGroup>
</Project>

You can also set the optional properties, such as Title, PackageDescription, and PackageTags, as described in MSBuild pack targets, Controlling dependency assets, and NuGet metadata properties.

Note

For packages built for public consumption, pay special attention to the PackageTags property, as tags help others find your package and understand what it does.

For details on declaring dependencies and specifying version numbers, see Package references in project files and Package versioning. It is also possible to surface assets from dependencies directly in the package by using the <IncludeAssets> and <ExcludeAssets> attributes. For more information, seee Controlling dependency assets.

Choose a unique package identifier and set the version number

The package identifier and the version number are the two most important values in the project because they uniquely identify the exact code that's contained in the package.

Best practices for the package identifier:

  • Uniqueness: The identifier must be unique across nuget.org or whatever gallery hosts the package. Before deciding on an identifier, search the applicable gallery to check if the name is already in use. To avoid conflicts, a good pattern is to use your company name as the first part of the identifier, such as Contoso..
  • Namespace-like names: Follow a pattern similar to namespaces in .NET, using dot notation instead of hyphens. For example, use Contoso.Utility.UsefulStuff rather than Contoso-Utility-UsefulStuff or Contoso_Utility_UsefulStuff. Consumers also find it helpful when the package identifier matches the namespaces used in the code.
  • Sample Packages: If you produce a package of sample code that demonstrates how to use another package, attach .Sample as a suffix to the identifier, as in Contoso.Utility.UsefulStuff.Sample. (The sample package would of course have a dependency on the other package.) When creating a sample package, use the contentFiles value in <IncludeAssets>. In the content folder, arrange the sample code in a folder called \Samples\<identifier> as in \Samples\Contoso.Utility.UsefulStuff.Sample.

Best practices for the package version:

  • In general, set the version of the package to match the project (or assembly), though this is not strictly required. This is a simple matter when you limit a package to a single assembly. Overall, remember that NuGet itself deals with package versions when resolving dependencies, not assembly versions.
  • When using a non-standard version scheme, be sure to consider the NuGet versioning rules as explained in Package versioning. NuGet is mostly semver 2 compliant.

For information on dependency resolution, see Dependency resolution with PackageReference. For older information that may also be helpful to better understand versioning, see this series of blog posts.

Add the NuGet.Build.Tasks.Pack package

If you are using MSBuild with a non-SDK-style project and PackageReference, add the NuGet.Build.Tasks.Pack package to your project.

  1. Open the project file and add the following after the <PropertyGroup> element:

    <ItemGroup>
      <!-- ... -->
      <PackageReference Include="NuGet.Build.Tasks.Pack" Version="5.2.0"/>
      <!-- ... -->
    </ItemGroup>
    
  2. Open a Developer command prompt (In the Search box, type Developer command prompt).

    You typically want to start the Developer Command Prompt for Visual Studio from the Start menu, as it will be configured with all the necessary paths for MSBuild.

  3. Switch to the folder containing the project file and type the following command to install the NuGet.Build.Tasks.Pack package.

    # Uses the project file in the current folder by default
    msbuild -t:restore
    

    Make sure that the MSBuild output indicates that the build completed successfully.

Run the msbuild -t:pack command

To build a NuGet package (a .nupkg file) from the project, run the msbuild -t:pack command, which also builds the project automatically:

In the Developer command prompt for Visual Studio, type the following command:

# Uses the project file in the current folder by default
msbuild -t:pack

The output shows the path to the .nupkg file.

Microsoft (R) Build Engine version 16.1.76+g14b0a930a7 for .NET Framework
Copyright (C) Microsoft Corporation. All rights reserved.

Build started 8/5/2019 3:09:15 PM.
Project "C:\Users\username\source\repos\ClassLib_DotNetStandard\ClassLib_DotNetStandard.csproj" on node 1 (pack target(s)).
GenerateTargetFrameworkMonikerAttribute:
Skipping target "GenerateTargetFrameworkMonikerAttribute" because all output files are up-to-date with respect to the input files.
CoreCompile:
  ...
CopyFilesToOutputDirectory:
  Copying file from "C:\Users\username\source\repos\ClassLib_DotNetStandard\obj\Debug\netstandard2.0\ClassLib_DotNetStandard.dll" to "C:\Use
  rs\username\source\repos\ClassLib_DotNetStandard\bin\Debug\netstandard2.0\ClassLib_DotNetStandard.dll".
  ClassLib_DotNetStandard -> C:\Users\username\source\repos\ClassLib_DotNetStandard\bin\Debug\netstandard2.0\ClassLib_DotNetStandard.dll
  Copying file from "C:\Users\username\source\repos\ClassLib_DotNetStandard\obj\Debug\netstandard2.0\ClassLib_DotNetStandard.pdb" to "C:\Use
  rs\username\source\repos\ClassLib_DotNetStandard\bin\Debug\netstandard2.0\ClassLib_DotNetStandard.pdb".
GenerateNuspec:
  Successfully created package 'C:\Users\username\source\repos\ClassLib_DotNetStandard\bin\Debug\AppLogger.1.0.0.nupkg'.
Done Building Project "C:\Users\username\source\repos\ClassLib_DotNetStandard\ClassLib_DotNetStandard.csproj" (pack target(s)).

Build succeeded.
    0 Warning(s)
    0 Error(s)

Time Elapsed 00:00:01.21

Automatically generate package on build

To automatically run msbuild -t:pack when you build or restore the project, add the following line to your project file within <PropertyGroup>:

<GeneratePackageOnBuild>true</GeneratePackageOnBuild>

When you run msbuild -t:pack on a solution, this packs all the projects in the solution that are packable ( property is set to true).

Note

When you automatically generate the package, the time to pack increases the build time for your project.

Test package installation

Before publishing a package, you typically want to test the process of installing a package into a project. The tests make sure that the necessarily files all end up in their correct places in the project.

You can test installations manually in Visual Studio or on the command line using the normal package installation steps.

Important

Packages are immutable. If you correct a problem, change the contents of the package and pack again, when you retest you will still be using the old version of the package until you clear your global packages folder. This is especially relevant when testing packages that don't use a unique prerelease label on every build.

Next Steps

Once you've created a package, which is a .nupkg file, you can publish it to the gallery of your choice as described on Publishing a Package.

You might also want to extend the capabilities of your package or otherwise support other scenarios as described in the following topics:

Finally, there are additional package types to be aware of: