blazor.web.js and blazor.server.js request return 404 when Project OutputType is WinExe

[jinjaeyeon]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Our team has internally built and is using a tooling application with .NET 8.0 and Blazor. Because the app needs to run in the background on each individual’s Windows machine, we set the OutputType to WinExe.

With the release of .NET version 10.0, we started upgrading the app, but every page was rendering as a blank page. We tried various solutions we found, but none had any effect.

However, after removing the <OutputType>WinExe</OutputType> option from the .csproj—an option we had assumed would be harmless—and testing again, the pages began displaying correctly.

Expected Behavior

No response

Steps To Reproduce

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Exceptions (if any)

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.NET Version

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Anything else?

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[javiercn]

@jinjaeyeon thanks for contacting us.

Does your app reference the Microsoft.NET.Sdk.Web on the project you are publishing? Does that project include any .razor file? Your project needs a reference to the Microsoft.NET.Sdk.Web and you need to either have a .razor file present on the project or set <RequiresAspNetWebAssets>true</RequiresAspNetWebAssets> in your csproj file.

We no longer embed blazor.server.js or blazor.web.js in our assemblies and they are only brought in when we detect the app is using Blazor. We do so by looking for the presence of .razor files, since we don't have any other mechanism available at the time the assets must be imported.

[jinjaeyeon]

@javiercn

Project Sdk is <Project Sdk="Microsoft.NET.Sdk.Web"> ... </Project> right.

15 .razor files include in csproj. And I tried add <RequiresAspNetWebAssets>true</RequiresAspNetWebAssets> to csproj but same problem.

When <OutputType/> no contains into csproj, published app generate blazor.server.js and blazor.web.js to <OutputPath>\wwwroot\_framework directory. But <OuptutType>WinExe</OutputType> contains into csproj, No generate any blazor js file(s).

[oroztocil]

@jinjaeyeon Can you please provide a minimal reproduction of the problem? Ideally in the form of a project in a GitHub repository.

[jinjaeyeon]

@oroztocil cc @javiercn

This is sample: https://github.com/jinjaeyeon/Net10BlazorProblemSample

Output dir is problem reproducted. NoWinExe dir is normal situation (<OutputType>WinExe<OutputType> is not contains in csproj).

[javiercn]

Traced down to <Target Name="_AddBlazorFrameworkStaticWebAssets" Condition="'$(OutputType)' == 'Exe'">

The issue is because we don't check for WinExe.

You can copy the logic in the target file into your own project and update the condition to work around this.

Our team has internally built and is using a tooling application with .NET 8.0 and Blazor. Because the app needs to run in the background on each individual’s Windows machine, we set the OutputType to WinExe.

The recommendation here would be to run the app as a service.

Alternatively, you could copy the blazor.web.js file and dump it into the appropriate location in the wwwroot folder.