In ASP.NET Core, you can structure your application using multiple projects, such as class libraries and web applications. To enable one project to use the functionality of another, you need to add a project reference. The .NET Command Line Interface (CLI) provides a simple command to add a reference to another project. This guide will walk you through the steps to add a project reference using the CLI.

What is a Project Reference?

A project reference allows one project to use the code and resources of another project within the same solution. This is particularly useful for organizing code into reusable libraries or components. When you add a project reference, the dependent project is built whenever the referencing project is built.

How to Add a Project Reference

To add a reference to another project using the CLI, 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: Use the dotnet add reference Command

Use the following command to add a reference to another project:

dotnet add <ProjectName>.csproj reference <PathToOtherProject>.csproj

In this command:

• <ProjectName> is the name of your current project file (the one you want to add the reference to).
• <PathToOtherProject> is the relative path to the project file of the project you want to reference.

Example

Suppose you have a web application project named MyWebApp and a class library project named Utilities. You want to add a reference to the Utilities project from the MyWebApp project. You would do the following:

cd MyWebApp
dotnet add reference ../Utilities/Utilities.csproj

After executing this command, you should see output indicating that the reference has been added successfully.

Verifying the Reference

To verify that the reference has been added, you can open the project file (MyWebApp.csproj) in a text editor. You should see an entry for the referenced project:

<ItemGroup>
    <ProjectReference Include="..\Utilities\Utilities.csproj" />
</ItemGroup>

This entry confirms that the Utilities project is now referenced in the MyWebApp project.

Building the Project

After adding the reference, you can build your project to ensure that everything is set up correctly:

dotnet build

This command compiles the project and its dependencies, including the referenced project.

Conclusion

Adding a reference to another project in an ASP.NET Core application using the CLI is a straightforward process that helps you organize your code effectively. By following the steps outlined in this guide, you can easily set up project references, allowing for better code reuse and modularity in your applications. Understanding how to manage project references is essential for any .NET developer working on complex applications.