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

Article
08/17/2022
5 minutes to read

Applies to: Visual Studio Visual Studio for Mac Visual Studio Code

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.

Currently, 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.

Starting in Visual Studio 2022 Preview 2, 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

Prerequisites

Make sure to install the following:

Visual Studio 2022 Preview 2 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
Vue CLI (https://cli.vuejs.org/)

Create the frontend app

In the Start window (choose File > Start Window to open), select Create a new project.
Search for Vue in the search bar at the top and then select Standalone JavaScript Vue Template or Standalone TypeScript Vue Template.
Give your project and solution a name. When you get to the Additional information window, be sure to check the Add integration for Empty ASP.NET Web API Project option. This option adds files to your Vue template so that it can be hooked up later with the ASP.NET Core project.

Once the project is created, you see some new and modified files:

aspnetcore-https.js
vue.config.json (modified)
HelloWorld.vue (modified)
package.json (modified)

Create the backend app

In Solution Explorer, right-click the solution name, hover over Add, and then select New Project.
Search and select the ASP.NET Core Web API project.
Give your project and solution a name. When you get to the Additional information window, select .NET 6.0 as your target framework.

Once the project is created, Solution Explorer should look like this:

Open launchSettings.json from the Properties folder, and under the profiles section for the backend app, change the default ports to 5001 and 5003.

"profiles": {
  "yourbackendapp": {
    "commandName": "Project",
    "launchUrl": "swagger",
    "environmentVariables": {
      "ASPNETCORE_ENVIRONMENT": "Development"
    },
    "applicationUrl": "https://localhost:5001;http://localhost:5003",
    "dotnetRunMessages": true
  },

Set the project properties

In Solution Explorer, right-click the ASP.NET Core project and choose Properties.
Go to the Debug menu and select Open debug launch profiles UI option. Clear the Launch browser option.

Note

Currently, launch.json must be located under the .vscode folder.

Set the startup project

In Solution Explorer, right-click the solution name and select Set Startup Project. Change the startup project from Single startup project to Multiple startup projects. Select Start for each project’s action.
Next, select the backend project and move it above the frontend, so that it starts up first.

Start the project

Before you start the project, 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:5001.
Then, go to the vue.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:5001',
```
To start the project, press F5 or select the Start button at the top of the window. You will see two command prompts appear:
- The ASP.NET Core API project running
- The Vue CLI running the vue-cli-service serve command
Note

Check console output for messages, such as a message instructing you to update your version of Node.js.

You should see the Vue app appear, that 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.

In Solution Explorer, right-click the ASP.NET Core project and choose Add > Project Reference.
Select the Vue project and choose OK.
Right-click the ASP.NET Core project in Solution Explorer and choose Unload project.

This opens the .csproj file for the project.
In the .csproj file, update the project reference and add <ReferenceOutputAssembly> with the value set to false.

When you've updated the reference, it should look like this (substituting your own project folder and project name).
```
<ProjectReference Include="..\vueprojectfolder\vueprojectname.esproj">
    <ReferenceOutputAssembly>false</ReferenceOutputAssembly>
</ProjectReference>
```
Right-click the ASP.NET Core project and choose Reload Project.
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, et al.

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.

You can modify the npm run build command using the Production Build Command in the Vue project properties. To modify it, right-click the Vue project in Solution Explorer and choose Properties.

Troubleshooting

Proxy error

You may see the following error:

[HPM] Error occurred while trying to proxy request /weatherforecast from localhost:4200 to https://localhost:5001 (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 5002 in launchSettings.json and vue.config.js.

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 Vue CLI. After you update the Vue 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 5001. To resolve:

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

"httpPort": 5003, 
"sslPort": 5001

Alternatively, reset using the following method:

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