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Use React with ASP.NET Core

  • Artikkeli

Note

This isn't the latest version of this article. For the current release, see the .NET 9 version of this article.

Warning

This version of ASP.NET Core is no longer supported. For more information, see the .NET and .NET Core Support Policy. For the current release, see the .NET 9 version of this article.

Important

This information relates to a pre-release product that may be substantially modified before it's commercially released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

For the current release, see the .NET 9 version of this article.

Visual Studio provides project templates for creating single-page apps (SPAs) based on JavaScript frameworks such as Angular, React, and Vue that have an ASP.NET Core backend. These templates:

  • Create a Visual Studio solution with a frontend project and a backend project.
  • Use the Visual Studio project type for JavaScript and TypeScript (.esproj) for the frontend.
  • Use an ASP.NET Core project for the backend.

Projects created by using the Visual Studio templates can be run from the command line on Windows, Linux, and macOS. To run the app, use dotnet run --launch-profile https to run the server project. Running the server project automatically starts the frontend JavaScript development server. The https launch profile is currently required.

Visual Studio tutorial

To get started, follow the Create an ASP.NET Core app with React tutorial in the Visual Studio documentation.

For more information, see JavaScript and TypeScript in Visual Studio

ASP.NET Core SPA templates

Visual Studio includes templates for building ASP.NET Core apps with a JavaScript or TypeScript frontend. These templates are available in Visual Studio 2022 version 17.8 or later with the ASP.NET and web development workload installed.

The Visual Studio templates for building ASP.NET Core apps with a JavaScript or TypeScript frontend offer the following benefits:

  • Clean project separation for the frontend and backend.
  • Stay up-to-date with the latest frontend framework versions.
  • Integrate with the latest frontend framework command-line tooling, such as Vite.
  • Templates for both JavaScript & TypeScript (only TypeScript for Angular).
  • Rich JavaScript and TypeScript code editing experience.
  • Integrate JavaScript build tools with the .NET build.
  • npm dependency management UI.
  • Compatible with Visual Studio Code debugging and launch configuration.
  • Run frontend unit tests in Test Explorer using JavaScript test frameworks.

Legacy ASP.NET Core SPA templates

Earlier versions of the .NET SDK included what are now legacy templates for building SPA apps with ASP.NET Core. For documentation on these older templates, see the ASP.NET Core 7.0 version of the SPA overview and the Angular and React articles.

The ASP.NET Core with React project template provides a convenient starting point for ASP.NET Core apps using React and Create React App (CRA) to implement a rich, client-side user interface (UI).

The project template is equivalent to creating both an ASP.NET Core project to act as a web API and a CRA React project to act as a UI. This project combination offers the convenience of hosting both projects in a single ASP.NET Core project that can be built and published as a single unit.

The project template isn't meant for server-side rendering (SSR). For SSR with React and Node.js, consider Next.js or Razzle.

Create a new app

Create a new project from a command prompt using the command dotnet new react in an empty directory. For example, the following commands create the app in a my-new-app directory and switch to that directory:

dotnet new react -o my-new-app
cd my-new-app

Run the app from either Visual Studio or the .NET CLI:

Open the generated .csproj file, and run the app as normal from there.

The build process restores npm dependencies on the first run, which can take several minutes. Subsequent builds are much faster.

The project template creates an ASP.NET Core app and a React app. The ASP.NET Core app is intended to be used for data access, authorization, and other server-side concerns. The React app, residing in the ClientApp subdirectory, is intended to be used for all UI concerns.

Add pages, images, styles, modules, etc.

The ClientApp directory is a standard CRA React app. See the official CRA documentation for more information.

There are slight differences between the React app created by this template and the one created by CRA itself; however, the app's capabilities are unchanged. The app created by the template contains a Bootstrap-based layout and a basic routing example.

Install npm packages

To install third-party npm packages, use a command prompt in the ClientApp subdirectory. For example:

cd ClientApp
npm install <package_name>

Publish and deploy

In development, the app runs in a mode optimized for developer convenience. For example, JavaScript bundles include source maps (so that when debugging, you can see your original source code). The app watches JavaScript, HTML, and CSS file changes on disk and automatically recompiles and reloads when it sees those files change.

In production, serve a version of your app that's optimized for performance. This is configured to happen automatically. When you publish, the build configuration emits a minified, transpiled build of your client-side code. Unlike the development build, the production build doesn't require Node.js to be installed on the server.

You can use standard ASP.NET Core hosting and deployment methods.

Run the CRA server independently

The project is configured to start its own instance of the CRA development server in the background when the ASP.NET Core app starts in development mode. This is convenient because it means you don't have to run a separate server manually.

There's a drawback to this default setup. Each time you modify your C# code and your ASP.NET Core app needs to restart, the CRA server restarts. A few seconds are required to start back up. If you're making frequent C# code edits and don't want to wait for the CRA server to restart, run the CRA server externally, independently of the ASP.NET Core process.

To run the CRA server externally, switch to the ClientApp subdirectory in a command prompt and launch the CRA development server:

cd ClientApp
npm start

When you start your ASP.NET Core app, it won't launch a CRA server. The instance you started manually is used instead. This enables it to start and restart faster. It's no longer waiting for your React app to rebuild each time.

Configure proxy middleware for SignalR

For more information, see http-proxy-middleware.

Additional resources

The updated React project template provides a convenient starting point for ASP.NET Core apps using React and create-react-app (CRA) conventions to implement a rich, client-side user interface (UI).

The template is equivalent to creating both an ASP.NET Core project to act as an API backend, and a standard CRA React project to act as a UI, but with the convenience of hosting both in a single app project that can be built and published as a single unit.

The React project template isn't meant for server-side rendering (SSR). For SSR with React and Node.js, consider Next.js or Razzle.

Create a new app

Create a new project from a command prompt using the command dotnet new react in an empty directory. For example, the following commands create the app in a my-new-app directory and switch to that directory:

dotnet new react -o my-new-app
cd my-new-app

Run the app from either Visual Studio or the .NET CLI:

Open the generated .csproj file, and run the app as normal from there.

The build process restores npm dependencies on the first run, which can take several minutes. Subsequent builds are much faster.

The project template creates an ASP.NET Core app and a React app. The ASP.NET Core app is intended to be used for data access, authorization, and other server-side concerns. The React app, residing in the ClientApp subdirectory, is intended to be used for all UI concerns.

Add pages, images, styles, modules, etc.

The ClientApp directory is a standard CRA React app. See the official CRA documentation for more information.

There are slight differences between the React app created by this template and the one created by CRA itself; however, the app's capabilities are unchanged. The app created by the template contains a Bootstrap-based layout and a basic routing example.

Install npm packages

To install third-party npm packages, use a command prompt in the ClientApp subdirectory. For example:

cd ClientApp
npm install --save <package_name>

Publish and deploy

In development, the app runs in a mode optimized for developer convenience. For example, JavaScript bundles include source maps (so that when debugging, you can see your original source code). The app watches JavaScript, HTML, and CSS file changes on disk and automatically recompiles and reloads when it sees those files change.

In production, serve a version of your app that's optimized for performance. This is configured to happen automatically. When you publish, the build configuration emits a minified, transpiled build of your client-side code. Unlike the development build, the production build doesn't require Node.js to be installed on the server.

You can use standard ASP.NET Core hosting and deployment methods.

Run the CRA server independently

The project is configured to start its own instance of the CRA development server in the background when the ASP.NET Core app starts in development mode. This is convenient because it means you don't have to run a separate server manually.

There's a drawback to this default setup. Each time you modify your C# code and your ASP.NET Core app needs to restart, the CRA server restarts. A few seconds are required to start back up. If you're making frequent C# code edits and don't want to wait for the CRA server to restart, run the CRA server externally, independently of the ASP.NET Core process. To do so:

  1. Add a .env file to the ClientApp subdirectory with the following setting:

    BROWSER=none

    This will prevent your web browser from opening when starting the CRA server externally.

  2. In a command prompt, switch to the ClientApp subdirectory, and launch the CRA development server:

    cd ClientApp
npm start

  3. Modify your ASP.NET Core app to use the external CRA server instance instead of launching one of its own. In your Startup class, replace the spa.UseReactDevelopmentServer invocation with the following:

    spa.UseProxyToSpaDevelopmentServer("http://localhost:3000");

When you start your ASP.NET Core app, it won't launch a CRA server. The instance you started manually is used instead. This enables it to start and restart faster. It's no longer waiting for your React app to rebuild each time.

Important

"Server-side rendering" is not a supported feature of this template. Our goal with this template is to meet parity with "create-react-app". As such, scenarios and features not included in a "create-react-app" project (such as SSR) are not supported and are left as an exercise for the user.

Configure proxy middleware for SignalR

For more information, see http-proxy-middleware.

Additional resources