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Tooling for ASP.NET Core Blazor

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  • 12 minutes to read

This article describes tools for building Blazor apps on various platforms.

  1. Install the latest version of Visual Studio with the ASP.NET and web development workload.

  2. Create a new project.

  1. For a Blazor Server experience, choose the Blazor Server App template, which includes demonstration code and Bootstrap, or the Blazor Server App Empty template without demonstration code and Bootstrap. Select Next.

    For a Blazor WebAssembly experience, choose the Blazor WebAssembly App template, which includes demonstration code and Bootstrap, or the Blazor WebAssembly App Empty template without demonstration code and Bootstrap.

  1. For a Blazor WebAssembly experience, choose the Blazor WebAssembly App template. For a Blazor Server experience, choose the Blazor Server App template. Select Next.

  1. Provide a Project name and confirm that the Location is correct. Select Next.

  2. In the Additional information dialog, select the ASP.NET Core Hosted checkbox for a hosted Blazor WebAssembly app. Select Create.

    For information on the two Blazor hosting models, Blazor WebAssembly (standalone and hosted) and Blazor Server, see ASP.NET Core Blazor hosting models.

  3. Press Ctrl+F5 (Windows) or ⌘+F5 (macOS) to run the app.

    When running a hosted Blazor WebAssembly solution in Visual Studio, the startup project of the solution is the Server project.

For more information on trusting the ASP.NET Core HTTPS development certificate, see Enforce HTTPS in ASP.NET Core.

Important

When executing a hosted Blazor WebAssembly app, run the app from the solution's Server project.

When the app is launched, only the Properties/launchSettings.json file in the Server project is used.

Use the .NET command-line interface (CLI) to execute commands in a Linux command shell.

  1. Install the latest version of the .NET Core SDK. If you previously installed the SDK, you can determine your installed version by executing the following command:

    dotnet --version

  2. Install the latest version of Visual Studio Code.

  3. Install the latest C# for Visual Studio Code extension.

  1. For a Blazor Server experience with demonstration code and Bootstrap, execute the following command:

    dotnet new blazorserver -o WebApplication1

    Alternatively, create an app without demonstration code and Bootstrap using the blazorserver-empty project template:

    dotnet new blazorserver-empty -o WebApplication1

    For a Blazor WebAssembly experience with demonstration code and Bootstrap, execute the following command:

    dotnet new blazorwasm -o WebApplication1

    Alternatively, create an app without demonstration code and Bootstrap using the blazorwasm-empty project template:

    dotnet new blazorwasm-empty -o WebApplication1

    For a hosted Blazor WebAssembly experience with demonstration code and Bootstrap, add the hosted option (-ho/--hosted) to the command:

    dotnet new blazorwasm -o WebApplication1 -ho

    Alternatively, create a hosted Blazor WebAssembly app without demonstration code and Bootstrap using the blazorwasm-empty template with the hosted option:

    dotnet new blazorwasm-empty -o WebApplication1 -ho

    For information on the two Blazor hosting models, Blazor WebAssembly (standalone and hosted) and Blazor Server, see ASP.NET Core Blazor hosting models.

  1. For a Blazor WebAssembly experience, execute the following command:

    dotnet new blazorwasm -o WebApplication1

    For a hosted Blazor WebAssembly experience, add the hosted option (-ho or --hosted) option to the command:

    dotnet new blazorwasm -o WebApplication1 -ho

    For a Blazor Server experience, execute the following command:

    dotnet new blazorserver -o WebApplication1

    For information on the two Blazor hosting models, Blazor WebAssembly (standalone and hosted) and Blazor Server, see ASP.NET Core Blazor hosting models.

  1. Open the WebApplication1 folder in Visual Studio Code.

  2. The IDE requests that you add assets to build and debug the project. Select Yes.

    If Visual Studio Code doesn't offer to create the assets automatically, use the following files:

    .vscode/launch.json (configured for launch and debug of a Blazor WebAssembly app):

{
  "version": "0.2.0",
  "configurations": [
    {
      "type": "blazorwasm",
      "name": "Launch and Debug Blazor WebAssembly Application",
      "request": "launch",
      "cwd": "${workspaceFolder}",
      "browser": "edge"
    }
  ]
}

.vscode/tasks.json:

{
  "version": "2.0.0",
  "tasks": [
    {
      "label": "build",
      "command": "dotnet",
      "type": "shell",
      "args": [
        "build",
        "/property:GenerateFullPaths=true",
        "/consoleloggerparameters:NoSummary",
       ],
       "group": "build",
       "presentation": {
          "reveal": "silent"
       },
       "problemMatcher": "$msCompile"
    }
  ]
}

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [
        {
            "type": "blazorwasm",
            "name": "Launch and Debug Blazor WebAssembly Application",
            "request": "launch",
            "cwd": "${workspaceFolder}",
            "browser": "edge"
        }
    ]
}

.vscode/tasks.json:

{
    // See https://go.microsoft.com/fwlink/?LinkId=733558
    // for the documentation about the tasks.json format
    "version": "2.0.0",
    "tasks": [
        {
            "label": "build",
            "command": "dotnet",
            "type": "shell",
            "args": [
                "build",
                // Ask dotnet build to generate full paths for file names.
                "/property:GenerateFullPaths=true",
                // Do not generate summary otherwise it leads to duplicate errors in Problems panel
                "/consoleloggerparameters:NoSummary",
            ],
            "group": "build",
            "presentation": {
                "reveal": "silent"
            },
            "problemMatcher": "$msCompile"
        }
    ]
}

The project's Properties/launchSettings.json file includes the inspectUri property for the debugging proxy for any profiles in the profiles section of the file:

"inspectUri": "{wsProtocol}://{url.hostname}:{url.port}/_framework/debug/ws-proxy?browser={browserInspectUri}",

Hosted Blazor WebAssembly launch and task configuration

For hosted Blazor WebAssembly solutions, add (or move) the .vscode folder with launch.json and tasks.json files to the solution's parent folder, which is the folder that contains the typical project folders: Client, Server, and Shared. Update or confirm that the configuration in the launch.json and tasks.json files execute a hosted Blazor WebAssembly app from the Server project.

Important

When executing a hosted Blazor WebAssembly app, run the app from the solution's Server project.

When the app is launched, only the Properties/launchSettings.json file in the Server project is used.

Examine the Properties/launchSettings.json file and determine the URL of the app from the applicationUrl property. Depending on the framework version, the URL protocol is either secure (HTTPS) https://localhost:{PORT} or insecure (HTTP) http://localhost:{PORT}, where the {PORT} placeholder is an assigned port. Note the URL for use in the launch.json file.

In the launch configuration of the .vscode/launch.json file:

  • Set the current working directory (cwd) to the Server project folder.
  • Indicate the app's URL with the url property. Use the value recorded earlier from the Properties/launchSettings.json file.
"cwd": "${workspaceFolder}/{SERVER APP FOLDER}",
"url": "{URL}"

In the preceding configuration:

  • The {SERVER APP FOLDER} placeholder is the Server project's folder, typically Server.
  • The {URL} placeholder is the app's URL, which is specified in the app's Properties/launchSettings.json file in the applicationUrl property.

If Google Chrome is preferred over Microsoft Edge, update or add an additional property of "browser": "chrome" to the configuration.

The following example .vscode/launch.json file:

  • Sets the current working directory to the Server folder.
  • Sets the URL for the app to http://localhost:7268.
  • Changes the default browser from Microsoft Edge to Google Chrome.
"cwd": "${workspaceFolder}/Server",
"url": "http://localhost:7268",
"browser": "chrome"

The complete .vscode/launch.json file:

{
  "version": "0.2.0",
  "configurations": [
    {
      "type": "blazorwasm",
      "name": "Launch and Debug Blazor WebAssembly Application",
      "request": "launch",
      "cwd": "${workspaceFolder}/Server",
      "url": "http://localhost:7268",
      "browser": "chrome"
    }
  ]
}

In .vscode/tasks.json, add a build argument that specifies the path to the Server app's project file:

"${workspaceFolder}/{SERVER APP FOLDER}/{PROJECT NAME}.csproj",

In the preceding argument:

  • The {SERVER APP FOLDER} placeholder is the Server project's folder, typically Server.
  • The {PROJECT NAME} placeholder is the app's name, typically based on the solution's name followed by .Server in an app generated from the Blazor WebAssembly project template.

An example .vscode/tasks.json file with a Server project named BlazorHosted in the Server folder of the solution:

{
  "version": "2.0.0",
  "tasks": [
    {
      "label": "build",
      "command": "dotnet",
      "type": "process",
        "args": [
          "build",
          "${workspaceFolder}/Server/BlazorHosted.Server.csproj",
          "/property:GenerateFullPaths=true",
          "/consoleloggerparameters:NoSummary",
        ],
        "group": "build",
        "presentation": {
          "reveal": "silent"
        },
        "problemMatcher": "$msCompile"
    }
  ]
}
  1. Press Ctrl+F5 (Windows) or ⌘+F5 (macOS) to run the app.

Note

Only browser debugging is supported at this time.

You can't automatically rebuild the backend Server app of a hosted Blazor WebAssembly solution during debugging, for example by running the app with dotnet watch run.

.vscode/launch.json (launch configuration):

...
"cwd": "${workspaceFolder}/{SERVER APP FOLDER}",
...

In the preceding configuration for the current working directory (cwd), the {SERVER APP FOLDER} placeholder is the Server project's folder, typically "Server".

If Microsoft Edge is used and Google Chrome isn't installed on the system, add an additional property of "browser": "edge" to the configuration.

Example for a project folder of Server and that spawns Microsoft Edge as the browser for debug runs instead of the default browser Google Chrome:

...
"cwd": "${workspaceFolder}/Server",
"browser": "edge"
...

.vscode/tasks.json (dotnet command arguments):

...
"${workspaceFolder}/{SERVER APP FOLDER}/{PROJECT NAME}.csproj",
...

In the preceding argument:

  • The {SERVER APP FOLDER} placeholder is the Server project's folder, typically "Server".
  • The {PROJECT NAME} placeholder is the app's name, typically based on the solution's name followed by ".Server" in an app generated from the Blazor project template.

The following example from the tutorial for using SignalR with a Blazor WebAssembly app uses a project folder name of Server and a project name of BlazorWebAssemblySignalRApp.Server:

...
"args": [
  "build",
    "${workspaceFolder}/Server/BlazorWebAssemblySignalRApp.Server.csproj",
    ...
],
...
  1. Press Ctrl+F5 (Windows) or ⌘+F5 (macOS) to run the app.

Trust a development certificate

For more information, see Enforce HTTPS in ASP.NET Core.

  1. Install Visual Studio for Mac. When the installer requests the workloads to install, select .NET.

  2. Select New Project from the File menu or create a New project from the Start Window.

  1. In the sidebar, select Web and Console > App.

    For a Blazor Server experience, choose the Blazor Server App template, which includes demonstration code and Bootstrap, or the Blazor Server App Empty template without demonstration code and Bootstrap. Select Continue.

    For a Blazor WebAssembly experience, choose the Blazor WebAssembly App template, which includes demonstration code and Bootstrap, or the Blazor WebAssembly App Empty template without demonstration code and Bootstrap.

    For information on the two Blazor hosting models, Blazor WebAssembly (standalone and hosted) and Blazor Server, see ASP.NET Core Blazor hosting models.

  1. In the sidebar, select Web and Console > App.

    For a Blazor WebAssembly experience, choose the Blazor WebAssembly App template. For a Blazor Server experience, choose the Blazor Server App template. Select Continue.

    For information on the two Blazor hosting models, Blazor WebAssembly (standalone and hosted) and Blazor Server, see ASP.NET Core Blazor hosting models.

  1. Confirm that Authentication is set to No Authentication. Select Continue.

  2. For a hosted Blazor WebAssembly experience, select the ASP.NET Core Hosted checkbox.

  3. In the Project name field, name the app WebApplication1. Select Create.

  4. Select the Start Without Debugging command from the Debug menu to run the app without the debugger. Run the app with Debug > Start Debugging or the Run (▶) button to run the app with the debugger.

If a prompt appears to trust the development certificate, trust the certificate and continue. The user and keychain passwords are required to trust the certificate. For more information on trusting the ASP.NET Core HTTPS development certificate, see Enforce HTTPS in ASP.NET Core.

Important

When executing a hosted Blazor WebAssembly app, run the app from the solution's Server project.

When the app is launched, only the Properties/launchSettings.json file in the Server project is used.

Visual Studio solution file (.sln)

A solution is a container to organize one or more related code projects. Visual Studio and Visual Studio for Mac use a solution file (.sln) to store settings for a solution. Solution files use a unique format and aren't intended to be edited directly.

Tooling outside of Visual Studio and Visual Studio for Mac can interact with solution files:

  • The .NET CLI can create solution files and list/modify the projects in solution files via the dotnet sln command. Other .NET CLI commands use the path of the solution file for various publishing, testing, and packaging commands.
  • Visual Studio Code can execute the dotnet sln command and other .NET CLI commands through its integrated terminal but doesn't use the settings in a solution file directly.

Throughout the Blazor documentation, solution is used to describe apps created from the Blazor WebAssembly project template with the ASP.NET Core Hosted option enabled or from a Blazor Hybrid project template. Apps produced from these project templates include a solution file (.sln) by default. For hosted Blazor WebAssembly apps where the developer isn't using Visual Studio or Visual Studio for Mac, the solution file can be ignored or deleted if it isn't used with .NET CLI commands.

For more information, see the following resources in the Visual Studio documentation:

Use Visual Studio Code for cross-platform Blazor development

Visual Studio Code is an open source, cross-platform Integrated Development Environment (IDE) that can be used to develop Blazor apps. Use the .NET CLI to create a new Blazor app for development with Visual Studio Code. For more information, see the Linux version of this article.

Use Visual Studio Code for cross-platform Blazor development

Visual Studio Code is an open source, cross-platform Integrated Development Environment (IDE) that can be used to develop Blazor apps. Use the .NET CLI to create a new Blazor app for development with Visual Studio Code. For more information, see the Linux version of this article.

Blazor template options

The Blazor framework provides templates for creating new apps for each of the two Blazor hosting models. The templates are used to create new Blazor projects and solutions regardless of the tooling that you select for Blazor development (Visual Studio, Visual Studio for Mac, Visual Studio Code, or the .NET command-line interface (CLI)):

  • Blazor Server project templates: blazorserver, blazorserver-empty
  • Blazor WebAssembly project templates: blazorwasm, blazorwasm-empty
  • Blazor Server project template: blazorserver
  • Blazor WebAssembly project template: blazorwasm

For more information on Blazor's hosting models, see ASP.NET Core Blazor hosting models. For more information on Blazor project templates, see ASP.NET Core Blazor project structure.

For more information on template options, see the following resources:

  • .NET default templates for dotnet new article in the .NET Core documentation:
  • Passing the help option (-h or --help) to the dotnet new CLI command in a command shell:
    • dotnet new blazorserver -h
    • dotnet new blazorwasm -h

.NET WebAssembly build tools

The .NET WebAssembly build tools are based on Emscripten, a compiler toolchain for the web platform. To install the build tools, use either of the following approaches:

  • For the ASP.NET and web development workload in the Visual Studio installer, select the .NET WebAssembly build tools option from the list of optional components.
  • Execute dotnet workload install wasm-tools in an administrative command shell.

When Ahead-of-time (AOT) compilation is used, WebAssembly Single Instruction, Multiple Data (SIMD) is supported, except for Apple Safari at this time. Use the <WasmEnableSIMD> property in the app's project file (.csproj) with a value of true:

<PropertyGroup>
  <WasmEnableSIMD>true</WasmEnableSIMD>
  <RunAOTCompilation>true</RunAOTCompilation>
</PropertyGroup>

To enable WebAssembly exception handling, use the <WasmEnableExceptionHandling> property in the app's project file (.csproj) with a value of true:

<PropertyGroup>
  <WasmEnableExceptionHandling>true</WasmEnableExceptionHandling>
</PropertyGroup>

Note

.NET WebAssembly build tools for .NET 6 projects

The wasm-tools workload installs the build tools for .NET 7 projects. However, the .NET 7 version of the build tools are incompatible with existing projects built with .NET 6. Projects using the build tools that must support both .NET 6 and .NET 7 must use multi-targeting.

Use the wasm-tools-net6 workload for .NET 6 projects when developing apps with the .NET 7 SDK. To install the wasm-tools-net6 workload, execute the following command from an administrative command shell:

dotnet workload install wasm-tools-net6

For more information, see the following resources:

The .NET WebAssembly build tools are based on Emscripten, a compiler toolchain for the web platform. To install the build tools, use either of the following approaches:

  • For the ASP.NET and web development workload in the Visual Studio installer, select the .NET WebAssembly build tools option from the list of optional components.
  • Run dotnet workload install wasm-tools in a command shell.

For more information, see the following resources:

Additional resources