Add migration guidance for existing F# MVC applications upgrading from .NET 10 to .NET 11.

[danroth27]

Description

F# MVC projects generated by earlier templates use the Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation package and call .AddRazorRuntimeCompilation(). Razor Runtime Compilation is obsolete in .NET 11. Unlike C# MVC projects, F# projects can't use the Razor source generator directly, so removing Runtime Compilation without additional changes causes the application to build successfully but fail when a view is requested:

InvalidOperationException: The view 'Index' was not found.

The .NET 11 F# MVC template now uses build- and publish-time Razor compilation and explicitly registers the generated <ApplicationName>.Views.dll assembly. Existing F# MVC applications that want to remove Razor Runtime Compilation should adopt the same setup.

Related product work:

• Regression: Opening MVC F# project after dotnet run shows an unhandled exception while processing the request due to missing files in .NET 11 RC2 aspnetcore#69220
• Runtime Compilation removal: Update MVC F# project template to resolve deprecated warnings aspnetcore#69114
• F# MVC template fix: [release/11.0] Fix compiled Razor views in F# MVC template aspnetcore#69300

Proposed guidance

Clarify that newly generated .NET 11 F# MVC projects already contain this configuration. The following steps are for existing projects migrating from an earlier version of .NET.

1. Remove the Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation package reference.

2. Remove the call to .AddRazorRuntimeCompilation().

3. Configure Razor compilation in the project file:

   <PropertyGroup>
     <UseRazorSourceGenerator>false</UseRazorSourceGenerator>
     <RazorCompileOnBuild>true</RazorCompileOnBuild>
     <RazorCompileOnPublish>true</RazorCompileOnPublish>
   </PropertyGroup>
   

4. Add MvcBuilderExtensions.fs  to the project before  Program.fs  because F# compilation order is significant:

<ItemGroup>
  <!-- Other F# source files -->
  <Compile Include="MvcBuilderExtensions.fs" />
  <Compile Include="Program.fs" />
</ItemGroup>

5. Add MvcBuilderExtensions.fs. Its namespace must match the application's root namespace:

open System open System.IO open System.Reflection open System.Runtime.CompilerServices open System.Runtime.Loader open Microsoft.AspNetCore.Mvc.ApplicationParts open Microsoft.Extensions.DependencyInjection

[<Extension>] type MvcBuilderExtensions =
    [<Extension>]
    static member AddCompiledRazorViews(builder: IMvcBuilder) =
        let applicationAssembly = Assembly.GetExecutingAssembly()
        let viewsAssemblyName = $"{applicationAssembly.GetName().Name}.Views"
        let viewsAssemblyPath =
            Path.Combine(AppContext.BaseDirectory, $"{viewsAssemblyName}.dll")
        let loadContext =
            AssemblyLoadContext.GetLoadContext(applicationAssembly)

        let viewsAssembly =
            if File.Exists(viewsAssemblyPath) then
                loadContext.LoadFromAssemblyPath(viewsAssemblyPath)
            else
                loadContext.LoadFromAssemblyName(AssemblyName(viewsAssemblyName))

        builder.PartManager.ApplicationParts.Add(
            CompiledRazorAssemblyPart(viewsAssembly))
        builder

6. Register the compiled views in Program.fs:

    .AddControllersWithViews()
    .AddCompiledRazorViews()

Explain that this configuration compiles Razor views during build and publish and registers the resulting views assembly with MVC. It avoids the obsolete Runtime Compilation dependency while allowing views to be discovered at runtime.

Page URL

https://learn.microsoft.com/en-us/aspnet/core/migration/100-to-110?view=aspnetcore-10.0&tabs=visual-studio

Content source URL

https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/migration/100-to-110.md

Document ID

3c76ffcd-7b47-b9b9-68a0-b25e375dabe9

Platform Id

542d0049-d2cb-7cae-1b4b-0d79ae30efaf

Article author

@wadepickett

Metadata

• ID: 3c76ffcd-7b47-b9b9-68a0-b25e375dabe9
• PlatformId: 542d0049-d2cb-7cae-1b4b-0d79ae30efaf
• Service: aspnet-core
• Sub-service: migration

Related Issues

[wadepickett]

Thanks for the great guidance details @danroth27, I will take this one and will be on it with this next sprint.