Tutorial: Create an ASP.NET Core app with Vue in Visual Studio

In this article, you learn how to build an ASP.NET Core project to act as an API backend and a Vue project to act as the UI.

Visual Studio includes ASP.NET Core Single Page Application (SPA) templates that support Angular, React, and Vue. The templates provide a built-in Client App folder in your ASP.NET Core projects that contains the base files and folders of each framework.

You can use the method described in this article to create ASP.NET Core Single Page Applications that:

• Put the client app in a separate project, outside from the ASP.NET Core project
• Create the client project based on the framework CLI installed on your computer

Note

This article describes the project creation process using the updated template in Visual Studio 2022 version 17.8, which uses the Vite CLI.

Prerequisites

Make sure to install the following:

• Visual Studio 2022 version 17.8 or later with the ASP.NET and web development workload installed. Go to the Visual Studio downloads page to install it for free. If you need to install the workload and already have Visual Studio, go to Tools > Get Tools and Features..., which opens the Visual Studio Installer. Choose the ASP.NET and web development workload, then choose Modify.
• npm (https://www.npmjs.com/), which is included with Node.js.

Create the frontend app

1. In the Start window (choose File > Start Window to open), select Create a new project.

   

2. Search for Vue in the search bar at the top and then select Vue and ASP.NET Core with either JavaScript or TypeScript as the selected language.

   

3. Name the project VueWithASP and then choose Create.

   Solution Explorer shows the following project information:

   

   Compared to the standalone Vue template, you see some new and modified files for integration with ASP.NET Core:

   • vite.config.json (modified)
   • HelloWorld.vue (modified)
   • package.json (modified)

Set the project properties

1. In Solution Explorer, right-click the VueWithASP.Server and choose Properties.

   

2. In the Properties page, open the Debug tab and select Open debug launch profiles UI option. Uncheck the Launch Browser option for the https profile or the profile named after the ASP.NET Core project, if present.

   

   This value prevents opening the web page with the source weather data.

   Note

   In Visual Studio, launch.json stores the startup settings associated with the Start button in the Debug toolbar. Currently, launch.json must be located under the .vscode folder.

3. Right-click the solution in Solution Explorer and select Properties. Verify that the Startup project settings are set to Multiple projects, and that the Action for both projects is set to Start.

Start the project

Press F5 or select the Start button at the top of the window to start the app. Two command prompts appear:

• The ASP.NET Core API project running
• The Vite CLI showing a message such as VITE v4.4.9 ready in 780 ms

Note

Check console output for messages. For example there might be a message to update Node.js.

The Vue app appears and is populated via the API. If you don't see the app, see Troubleshooting.

Publish the project

Starting in Visual Studio 2022 version 17.3, you can publish the integrated solution using the Visual Studio Publish tool.

Note

To use publish, create your JavaScript project using Visual Studio 2022 version 17.3 or later.

1. In Solution Explorer, right-click the VueWithASP.Server project and select Add > Project Reference.

   Make sure the vuewithasp.client project is selected.

2. Choose OK.

3. Right-click the ASP.NET Core project again and select Edit Project File.

   This opens the .csproj file for the project.

4. In the .csproj file, make sure the project reference includes a <ReferenceOutputAssembly> element with the value set to false.

   This reference should look like the following.

    <ProjectReference Include="..\vuewithasp.client\vuewithasp.client.esproj">
      <ReferenceOutputAssembly>false</ReferenceOutputAssembly>
    </ProjectReference>
   

5. Right-click the ASP.NET Core project and choose Reload Project if that option is available.

6. In Program.cs, make sure the following code is present.

   app.UseDefaultFiles();
   app.UseStaticFiles();
   
   // Configure the HTTP request pipeline.
   if (app.Environment.IsDevelopment())
   {
      app.UseSwagger();
      app.UseSwaggerUI();
   }
   

7. To publish, right click the ASP.NET Core project, choose Publish, and select options to match your desired publish scenario, such as Azure, publish to a folder, etc.

   The publish process takes more time than it does for just an ASP.NET Core project, since the npm run build command gets invoked when publishing. The BuildCommand runs npm run build by default.

Troubleshooting

Proxy error

You may see the following error:

[HPM] Error occurred while trying to proxy request /weatherforecast from localhost:4200 to https://localhost:5173 (ECONNREFUSED) (https://nodejs.org/api/errors.html#errors_common_system_errors)

If you see this issue, most likely the frontend started before the backend. Once you see the backend command prompt up and running, just refresh the Vue app in the browser.

Otherwise, if the port is in use, try incrementing the port number by 1 in launchSettings.json and vite.config.js.

Privacy error

You may see the following certificate error:

Your connection isn't private

Try deleting the Vue certificates from %appdata%\local\asp.net\https or %appdata%\roaming\asp.net\https, and then retry.

Verify ports

If the weather data doesn't load correctly, you may also need to verify that your ports are correct.

1. Make sure that the port numbers match. Go to the launchSettings.json file in your ASP.NET Core project (in the Properties folder). Get the port number from the applicationUrl property.

   If there are multiple applicationUrl properties, look for one using an https endpoint. It should look similar to https://localhost:7142.

2. Then, go to the vite.config.js file for your Vue project. Update the target property to match the applicationUrl property in launchSettings.json. When you update it, that value should look similar to this:

   target: 'https://localhost:7142/',
   

Outdated version of Vue

If you see the console message Could not find the file 'C:\Users\Me\source\repos\vueprojectname\package.json' when you create the project, you may need to update your version of the Vite CLI. After you update the Vite CLI, you may also need to delete the .vuerc file in C:\Users\[yourprofilename].

Docker

If you enable Docker support while creating the web API project, the backend may start up using the Docker profile and not listen on the configured port 5173. To resolve:

Edit the Docker profile in the launchSettings.json by adding the following properties:

"httpPort": 5175, 
"sslPort": 5173  

Alternatively, reset using the following method:

1. In the Solution properties, set your backend app as the startup project.
2. In the Debug menu, switch the profile using the Start button drop-down menu to the profile for your backend app.
3. Next, in the Solution properties, reset to multiple startup projects.

Next steps

For more information about SPA applications in ASP.NET Core, see Developing Single Page Apps. The linked article provides additional context for project files such as aspnetcore-https.js, although details of the implementation are different due to differences between the project templates and the Vue.js framework vs. other frameworks. For example, instead of a ClientApp folder, the Vue files are contained in a separate project.

For MSBuild information specific to the client project, see MSBuild properties for JSPS.