Blazor (client project) does not compile if cshtml file present in folder structure

[tn-5]

Describe the bug

It looks like the sdk uses the presence of a file with a ".cshtml" extension to detect that mvc is required. For a normal blazor project it then complains that:
The type or namespace name 'Mvc' does not exist in the namespace 'Microsoft.AspNetCore'

To Reproduce

• dotnet new blazor
• create file "a.cshtml" with no content in root of project
• dotnet build fails

Expected behavior

• Provide a more meaningful error message
• Allow the cshtml file to be excluded (currently if it is put in an itemgroup with build action=none it still has an effect, it should probably be ignored in those conditions)

Ideally what is required is any way (such as build action none in project file) to allow this file to be in the project structure but be ignored for the purposes of this.

[stefanjarina]

Hi,
I think we should use .razor instead of .cshtml file extension now.

At least this is in release notes for preview4:

New features in this preview release:

Templates updated to use the .razor file extension
_Imports.razor
...

Or is there still a need to use .cshtml and .razor together?

[tn-5]

The issue is not whether you use .razor or .cshtml. I understand that .razor is used for blazor. The issue is that there is no way to force the build system to ignore a specific file and not process it. Normally in VS if you tag a file with "build: none" it can stay part of the project file structure and will be ignored.

In our use case we have a dual client / server side project - we have one project file for the client side blazor project and one project file for the server side project. These are in same folder since it uses the same source files. The problem is that the server project requires the "_host.cshtml" for startup. If we compile the client project using this source structure it complains about the mvc error. If we delete or rename the file it works 100%. We can of course build this into the build scripts but fundamentally there needs to be a way to force a file to be ignored.

[danroth27]

In general we don't expect that Blazor to contain .cshtml files, but we can potentially look at making the experience better when you do.

[rynowak]

We definitely want to fail loudly by default if the project has something we don't understand.

You can exclude files like:

<ItemGroup>
  <Content Remove="Foo.cshtml" />
</ItemGroup>

[dylankdreyer]

I'm having a similar problem... I create a new Blazor solution using the Blazor extension. Initially it builds and runs fine. and then if I make changes to any of the razor pages and then try to build and run it... I get errors telling me that " The type or namespace name 'Mvc' does not exist in the namespace 'Microsoft.AspNetCore' for each razor page in the client project.... the client project is .net standard 2.0. I am stumped......

[danroth27]

@dylankdreyer Can you share the csproj file for the project that is failing to build?

[HelvioMarkman]

I have the same problem, I created a API but when I add a new Page to the Pages Folder come the same error dylankdreyer shows above.

[HelvioMarkman]

I have tried cshtml and razor.

[HelvioMarkman]

Looks like first error is "_framework/blazor.webassembly.js File not found"

[libcitra]

The problem was also bothering me.
("MVC" dose not exit)
However, I solved the problem by re-installing the latest vsix from here.
https://github.com/aspnet/Blazor/releases