dotnet scaffold – Next Generation Project Creation for .NET

[Sayed Ibrahim Hashimi]

Scaffolding in Visual Studio for ASP.NET Core projects has been a long-standing feature which was added shortly after ASP.NET Core was released. We have also had support for scaffolding from the command line for many years. From that command line experience, we have heard feedback from many users that we need an interactive CLI experience for scaffolding. To that goal, we have been working on a new interactive CLI tool, dotnet scaffold. This CLI tool has now been released as a preview. In this post we will describe how you can acquire and use this new command line tool. This tool is open source, you can view the code in the scaffolding repo. That repository contains the code for the dotnet scaffold tool as well as other scaffolding related code.

Installing dotnet scaffold​

To install this tool we will use the dotnet tool command. Execute the command below to get the latest released version installed.

dotnet tool install --global Microsoft.dotnet-scaffold

To install a specific version, visit the package on nuget.org. To install a specific version, visit the package on nuget.org. For more info on how to manage dotnet tools see the docs at .NET tools – .NET CLI | Microsoft Learn. In the command above we are installing the tool globally, but you can also install tools local to a folder. The .NET tools docs has more info on both of those approaches. tools – .NET CLI | Microsoft Learn](https://learn.microsoft.com/dotnet/core/tools/global-tools). In the command above we are installing the tool globally, but you can also install tools local to a folder. The .NET tools docs has more info on both of those approaches.

Using dotnet scaffold​

By default, dotnet scaffold is an interactive tool, meaning that you invoke it, and it will prompt you for info as needed. For automation, you can pass in all the parameter values, but we will discuss that in a future post. Before running dotnet scaffold, make sure to change directories (cd) to a folder where a .NET Core project exists. dotnet scaffold has support for the following ASP.NET Core project types.

• Web app
• Web API
• .NET Aspire
• Blazor

In this post we will focus on the Web app option to show you around dotnet scaffold, but all the scaffolders follow the same patterns and prompts.

I created a new ASP.NET Core 9 web app using dotnet new with the command dotnet new webapp -o MyWebApp. Then I used cd to change into that directory. When you run dotnet scaffold, you’ll be prompted to select the scaffolding category. See the screenshot below.



In the image above dotnet scaffold shows a list of the scaffolding categories that are currently supported. To navigate this menu, you will use the up and down arrow keys on your keyboard to select the desired category. In the future as we add more scaffolders more categories may appear. Here you’ll select the category of what you are wanting to generate into your project. For example, let’s explore the Razor Pages option. To select a category, navigate to it and type Return. That will take you into the selected option. If you select an incorrect option, you can always use Back under Navigation to go back to the previous selection. After entering the Razor Pages option, you will see the following options.



Now dotnet scaffold is prompting for the specific scaffolder which should be invoked. In this case we see two options, the first option is to create a new empty Razor Page. The second option will generate Razor Pages based on a model class that is a part of the project. Values will be persisted using Entity Framework into the selected database provider. Let’s first run through the Empty scaffolder and then the CRUD one. The empty scaffolder will generate a new Razor page with an associated code file. This is equivalent to running dotnet new page. The generated files will not have any customizations.

When you have the option Razor Page – Empty, selected hit the Return key to go into that option. After that you’ll be prompted to select the target project.



In this case we only have one, so we will select MyWebApp and hit the Return key. Then it will prompt for the name of the Razor Page to create. Give it the name About and hit the Return key. You’ll see the command working and then you should see the result below.



After this has completed you should see the files About.cshtml and About.cshtml.cs in the current working directory. When running this scaffold, it will use the current directory as the output location. Now let’s move on to see how the Razor Page EF option behaves.

Before invoking the EF scaffolders you need a model class for it to scaffold content for. I’ve created a new web app with the same command as before, dotnet new webapp -o MyWebApp and I’ve added the following class in the root of the project.

namespace MyWebApp;

public class Contact
{
    public int Id { get; set; }

    public string? Firstname { get; set; }

    public string? Lastname { get; set; }

    public string? Email { get; set; }
}

This is a very basic model class that can be used with Entity Framework. Now we are ready to invoke dotnet scaffold. After starting it, select the Razor Pages category and then the Razor Pages with Entity Framework (CRUD) option. It will prompt you to select the project, since there is only one project in this case you can hit Return because it’s already selected. Next dotnet scaffold will prompt you to select the model class as shown below.



Select Contact and hit the Return key to proceed. The next screen will prompt you for the name of the database context. For this example, give it the name ContactDbContext and hit the Return key. It’s recommended for this value to end with DbContext based on convention, but that is not required. See the following image.



After you hit the Return key, you will be prompted to select the database provider.



The following list summarizes the options on that screen.

• npgsql-efcore = PostgreSQL
• sqlserver-efcore = SQL Server
• sqlite-efcore = SQLite
• cosmos-efcore = Cosmos DB

To keep things simple, we will select the sqlite-efcore option. SQLite is a file based database and doesn’t have any external dependencies. Select that option and hit Return. You’ll be prompted to select what operations should be scaffolded. See the next image.



You can select an individual item to be created, or you can select the CRUD option to scaffold the full set of pages. Select the CRUD option. Next, you’ll be prompted if you want to include prerelease packages. Since we are working with .NET 9 preview, select Yes for that option and hit Return. After that the scaffolding operation will start. You’ll see a spinner showing that it is running, and it will emit messages for the operations that are taking place. When it is complete you should see a result similar to the following screenshot.



After performing this operation, the following changes will have been applied to the project.

• The project file has package references added for Entity Framework
• Program.cs has been updated to initialize the database connection
• appsettings.json has been updated with connection information
• ContactDbContext.cs has been created and added to the project root directory
• Razor Pages for CRUD operations has been added to the Pages folder

The content has been generated but the database has not yet been initialized. To prep the database, we need to create a migration and then update the database. Do that with the following commands.

• dotnet ef migrations add initialMigration
  • This will add a new migration named initialMigration. You can give it whatever name you prefer here.
• dotnet ef database update
  • This will apply the migrations to the database

After running those commands, you should be ready to run the app with the dotnet run command. After the app starts the URL will be shown in the terminal, open that URL in your browser with /ContactPages at the end of the URL. You should see something like the following.



Using this page you can create new contacts and manage existing ones as well. After you add some contacts they will appear on this page as shown below.



Now you have an ASP.NET Core Razor Pages web app which can manage a contact list. After scaffolding you will likely want to customize the generated content to suit your needs. You can use dotnet scaffold to scaffold other content as you develop your app.

Recap​

In this post we have used dotnet scaffold to add Razor Pages to a new ASP.NET Core .NET 9 web app. Keep an eye on this blog for more information on changes to dotnet scaffold. We are hoping that you will try out this new command line tool and provide us some feedback so that we can improve this going forward. In particular, we are very interested in feedback on the interactivity of this command line tool. The following section has info on how you can provide feedback.

Feedback​

You can share feedback with us by filing an issue in the Scaffolding repo. You can also send feedback via the Developer Community: report any bugs or issues via report a problem and share your suggestions for new features or improvements to existing ones. Let us know what you think in the comment below.

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