In ASP.NET Core projects, managing dependencies is essential for leveraging third-party libraries and tools. The .NET Command Line Interface (CLI) provides a straightforward way to add new packages to your project using the dotnet add package command. This guide will walk you through the steps to add a new package to your ASP.NET Core project.

What is dotnet add package?

The dotnet add package command is used to add a NuGet package to your project. This command updates the project file (e.g., .csproj) to include the specified package and automatically restores the dependencies.

When to Use dotnet add package

You should use the dotnet add package command when:

• You want to include a new library or tool in your project.
• You need to update an existing package to a newer version.
• You are working on a project that requires additional functionality provided by third-party packages.

How to Use dotnet add package

To add a new package to your ASP.NET Core project, follow these steps:

Step 1: Open Your Command Line Interface

Open your terminal (macOS/Linux) or command prompt (Windows) and navigate to the directory containing your ASP.NET Core project.

Step 2: Run the Add Package Command

Use the following command to add a new package:

dotnet add package <PackageName>

Replace <PackageName> with the name of the NuGet package you want to add. For example, to add the popular JSON library Newtonsoft.Json, you would run:

dotnet add package Newtonsoft.Json

Step 3: Verify the Package Installation

After running the command, you should see output indicating that the package has been added successfully. The project file will be updated to include the new package reference. You can verify the installation by checking the .csproj file, which should now contain an entry like this:

<PackageReference Include="Newtonsoft.Json" Version="13.0.1" />

(The version number may vary based on the latest available version at the time of installation.)

Example

Suppose you have an ASP.NET Core project named MyWebApp. To add the Newtonsoft.Json package, you would do the following:

cd MyWebApp
dotnet add package Newtonsoft.Json

After executing this command, the package will be added to your project, and you can start using it in your code.

Updating a Package

If you want to update an existing package to the latest version, you can use the following command:

dotnet add package <PackageName> --version <NewVersion>

For example, to update Newtonsoft.Json to version 13.0.2, you would run:

dotnet add package Newtonsoft.Json --version 13.0.2

This command updates the package to the specified version.

Conclusion

The dotnet add package command is a powerful tool for managing dependencies in ASP.NET Core projects. By following the steps outlined above, you can easily add new packages or update existing ones, enhancing the functionality of your applications. This command streamlines the process of integrating third-party libraries, allowing you to focus on developing your application without worrying about manual package management. Understanding how to effectively use this command is essential for any ASP.NET Core developer looking to leverage the vast ecosystem of NuGet packages available.