.NET Core 3.0: Razor views don't automatically recompile on change

Question

According to the documentation, Razor views should, by default, recompile on change on local environments for ASP.NET Core 3.0.

However, my project doesn't do this locally. If I change a view and refresh when I'm debugging locally, the change is not reflected. I have to stop the solution, re-run, and then see the change.

I am doing this on a default ASP.NET Core Web Application template on Visual Studio 2019 with ASP.NET Core 3.0.0 Preview 2 using Razor pages. Any idea if I need to change settings to enable this feature?

UPDATE NOV 2019 FOR 3.0 FULL RELEASE:

This question still gets a lot of views. A few answers have cited to add

services.AddControllersWithViews().AddRazorRuntimeCompilation(); 

To your ConfigureServices() function in Startup.cs after adding the Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation NuGet package. In my case, I am only using Razor Pages, so I don't call AddControllersWithViews(). Instead, this worked for me:

services.AddRazorPages().AddRazorRuntimeCompilation();

Solution 1

OK it looks like it's not supported yet :(

Runtime compilation removed As a consequence of cleaning up the ASP.NET Core shared framework to not depend on Roslyn, support for runtime compilation of pages and views has also been removed in this preview release. Instead compilation of pages and views is performed at build time. In a future preview update we will provide a NuGet packages for optionally enabling runtime compilation support in an app.

You can read more about the issue here https://github.com/aspnet/Announcements/issues/343

Applications that require runtime compilation or re-compilation of Razor files should:

• Add a reference to the Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation package. It'll be available as part of the 3.0.0-preview3 release.
• Update the application's ConfigureServices to include a call to AddMvcRazorRuntimeCompilation:

Solution 2

For ASP.NET Core 3 release version:

   services.AddControllersWithViews().AddRazorRuntimeCompilation();

https://docs.microsoft.com/en-us/aspnet/core/mvc/views/view-compilation?view=aspnetcore-3.0

It can also be enabled conditionally only for local development, quoted from the link:

Runtime compilation can be enabled such that it's only available for local development. Conditionally enabling in this manner ensures that the published output:

Uses compiled views.
Is smaller in size.
Doesn't enable file watchers in production.

   public Startup(IConfiguration configuration, IWebHostEnvironment env)
    {
        Configuration = configuration;
        Env = env;
    }

    public IWebHostEnvironment Env { get; set; }
    public IConfiguration Configuration { get; }

    public void ConfigureServices(IServiceCollection services)
    {
        IMvcBuilder builder = services.AddRazorPages();

#if DEBUG
            if (Env.IsDevelopment())
            {
                builder.AddRazorRuntimeCompilation();
            }
#endif
    }

Solution 3

To get runtime view compilation back in ASP.NET Core 3

1. Reference Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation
2. Call services.AddMvc().AddRazorRuntimeCompilation()
3. Remove Microsoft.VisualStudio.Web.CodeGeneration.Design if there's a version mismatch on the Microsoft.CodeAnalysis.Common package

Solution 4

Runtime compilation is enabled using the Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation package. To enable runtime compilation, apps must:

1. Install the Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation NuGet package.

2. Update the project's Startup.ConfigureServices method to include a call to AddRazorRuntimeCompilation:

services
    .AddControllersWithViews()
    .AddRazorRuntimeCompilation();

https://docs.microsoft.com/en-us/aspnet/core/mvc/views/view-compilation?view=aspnetcore-3.0

Solution 5

To get runtime Razor Views Compilation back in ASP.NET Core 3.1:

1. Install the Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation NuGet package.
2. Update the project's Startup.ConfigureServices method to include a call to AddRazorRuntimeCompilation.

3. services.AddRazorPages().AddRazorRuntimeCompilation();

   Razor file compilation in ASP.NET Core 3.1

View more solutions

Comments

[John-Luke Laue]

.cshtml razor views do get recompiled. Can you double check? Try adding a <h1>Test</h1>. Start the app, load the page. you should see "Test". Then change this to <h1>Foo</h1>. You should see "Foo".

[tarun713]

Doesn't work! I have to stop and start the solution. Captured it here: drive.google.com/file/d/1xOWQK2SvE2dskSYRdLz9X7iEmAv7BcTN/… - Have tried on multiple machines with the stock Razor Pages template.

[John-Luke Laue]

Are you running a on mac or pc or linux? Also, it might be an issue with the preview. Can you try using asp.net core 2.x?

[tarun713]

PC, Visual Studio 2019 preview. I tried with 2.2 and it works! So there's something that changed in 3.0.

[duck]

I am on a fully updated .net core 3/VS and had to add .AddRazorRuntimeCompilation(); Thank you!

[D.B. Fred]

AddMvcRazorRuntimeCompilation is AddRazorRuntimeCompilation with ASP.Net Core 3.0 Preview 4

[GeoffM]

Just a hint for others: when using Nuget, tick/check the "pre-release" box.

[Chet]

Is there a way to prevent the assets from being deployed to production? I tried some combinations of PrivateAssets on the PackageReference but it doesn't seem to work.

[dariol]

In Core 2.2 razor options has FileProviders and it works even without any recompilation. Just edit cshtml and voila. In core 3 this property is removed. :( github.com/aspnet/AspNetCore/issues/14572

[tkburbidge]

+1 because removing the Microsoft.VisualStudio.Web.CodeGeneration.Design package was the secret sauce that nowhere else mentions.

[Lynn Crumbling]

@tkburbidge I just ran into that issue with the package, too. Oddly enough, I had two lines that were exactly the same, back-to-back. I removed both, and could compile. Even more oddly, I then put the lines back in place, and was still able to compile.

[Tore Aurstad]

Tip about versions of the nuget package related to .Net core version. In case you use .Net Core 3.0, you cannot select the later versions of this Nuget package. But version 3.0.0 of the Nuget lib works with .Net Core 3.0. If you use .Net Core 3.1, you can select newer versions.

[Nathan]

For my .NET 5.0 only the following tags were needed inside .csproj <RazorCompileOnBuild>false</RazorCompileOnBuild> <RazorCompileOnPublish>false</RazorCompileOnPublish> <CopyRefAssembliesToPublishDirectory>false</CopyRefAssemblie‌​sToPublishDirectory> All other 2 & 3 steps also needed

[Marcelo Sader]

I'm using .NET Core 6 and it worked for me in all of projects.