ASP.NET Core Razor SDK Class Library - Area Views Not Within Areas Directory

Question

I'm trying to use the new Razor SDK to include my views within my class libraries where each class library is an MVC Area. If I include the views with an Areas directory in my class library e.g.

/MyLibrary/Areas/MyLibrary/Views/Home/Index.cshtml

Then it loads fine. However I don't like that I have to place them inside an Areas directory ideally the path would be:

/MyLibrary/Views/Home/Index.cshtml

I'm guessing I would have to use a view location expander to achieve this. However I don't know how to achieve this for a view which is contained within a class library and not within the application. So far I have come up with:

public class AreaViewLocationExpander : IViewLocationExpander {
    public virtual IEnumerable<string> ExpandViewLocations(ViewLocationExpanderContext context, IEnumerable<string> viewLocations) {
        return viewLocations.Concat(new[] {
            "../{2}/Views/{1}/{0}" + RazorViewEngine.ViewExtension
        });
    }

    public virtual void PopulateValues(ViewLocationExpanderContext context) { }
}

This throws the error:

InvalidOperationException: The view 'Index' was not found. The following locations were searched:

/Areas/MyLibrary/Views/Home/Index.cshtml

/Areas/MyLibrary/Views/Shared/Index.cshtml

/Views/Shared/Index.cshtml

/Pages/Shared/Index.cshtml

/../MyLibrary/Views/Home/Index.cshtml

But I'd imagine even if it did work locally, it wouldn't in production or when the library is packaged up in a NuGet package.

I'd appreciate it if someone could show me how this can be achieved. Thanks

I assumed the path would start at the application root. The class library is in the same directory as the application and therefore i’d have to go up a directory to get to it. I thought this would work during development atleast. — nfplee
when compiled the referenced libraries would be in the bin. — Nkosi
Check this out and see if it can be modified for views davepaquette.com/archive/2016/07/16/… — Nkosi
Yeah I’m aware of that but I need to load the views within the dll using a different path. — nfplee

nfplee nfplee · Accepted Answer · 2018-06-27T15:12:32

Step 1

From @pranavkm on GitHub:

The Razor Sdk uses well-known MSBuild metadata to calculate project relative paths. You may set the Link metadata for a file and Razor would use that. For instance, adding this to your project file would update all cshtml files to have a view engine path with the project name as a prefix:

<Target Name="UpdateTargetPath" BeforeTargets="AssignRazorGenerateTargetPaths">
  <ItemGroup>
    <RazorGenerate Include="@(RazorGenerate)" Link="$(TargetName)\%(RazorGenerate.RelativeDir)%(RazorGenerate.FileName)%(RazorGenerate.Extension)" />
  </ItemGroup>
</Target>

This does not work with runtime compilation - i.e. if you were to apply this to Application.csproj, it'll work for build time compiled views, but runtime compiled views would continue to use /Views/Home/Index.cshtml

Step 2

You would then need to add the following IViewLocationExpander:

public class AreaViewLocationExpander : IViewLocationExpander {
    public virtual IEnumerable<string> ExpandViewLocations(ViewLocationExpanderContext context, IEnumerable<string> viewLocations) {
        return viewLocations.Concat(new[] {
            "/{2}/Views/{1}/{0}" + RazorViewEngine.ViewExtension
        });
    }

    public virtual void PopulateValues(ViewLocationExpanderContext context) { }
}

ASP.NET Core Razor SDK Class Library - Area Views Not Within Areas Directory

1 Answers