A Razor file is compiled at runtime, when the associated MVC view is invoked. Build-time Razor file publishing is unsupported. Razor files can optionally be compiled at publish time and deployed with the app—using the precompilation tool.
A Razor file is compiled at runtime, when the associated Razor Page or MVC view is invoked. Build-time Razor file publishing is unsupported. Razor files can optionally be compiled at publish time and deployed with the app—using the precompilation tool.
A Razor file is compiled at runtime, when the associated Razor Page or MVC view is invoked. Razor files are compiled at both build and publish time using the [Razor SDK](xref:razor-pages/sdk).
Razor files with a *.cshtml* extension are compiled at both build and publish time using the [Razor SDK](xref:razor-pages/sdk). Runtime compilation may be optionally enabled by configuring your application.
Build- and publish-time compilation of Razor files is enabled by default by the Razor SDK. When enabled, runtime compilation complements build-time compilation, allowing Razor files to be updated if they are edited.
Build- and publish-time compilation of Razor files is enabled by default by the Razor SDK. Editing Razor files after they're updated is supported at build time. By default, only the compiled *Views.dll* and no *.cshtml* files or references assemblies required to compile Razor files are deployed with your app.
> The Razor SDK is effective only when no precompilation-specific properties are set in the project file. For instance, setting the *.csproj* file's `MvcRazorCompileOnPublish` property to `true` disables the Razor SDK.
If your project targets .NET Framework, install the [Microsoft.AspNetCore.Mvc.Razor.ViewCompilation](https://www.nuget.org/packages/Microsoft.AspNetCore.Mvc.Razor.ViewCompilation/) NuGet package:
The ASP.NET Core 2.x project templates implicitly set the `MvcRazorCompileOnPublish` property to `true` by default. Consequently, this element can be safely removed from the *.csproj* file.
> Razor file precompilation is unavailable when performing a [self-contained deployment (SCD)](/dotnet/core/deploying/#self-contained-deployments-scd) in ASP.NET Core 2.0.
Set the `MvcRazorCompileOnPublish` property to `true`, and install the [Microsoft.AspNetCore.Mvc.Razor.ViewCompilation](https://www.nuget.org/packages/Microsoft.AspNetCore.Mvc.Razor.ViewCompilation/) NuGet package. The following *.csproj* sample highlights these settings:
Prepare the app for a [framework-dependent deployment](/dotnet/core/deploying/#framework-dependent-deployments-fdd) with the [.NET Core CLI publish command](/dotnet/core/tools/dotnet-publish). For example, execute the following command at the project root:
A *\<project_name>.PrecompiledViews.dll* file, containing the compiled Razor files, is produced when precompilation succeeds. For example, the screenshot below depicts the contents of *Index.cshtml* within *WebApplication1.PrecompiledViews.dll*:
Build-time compilation is supplemented by runtime compilation of Razor files. ASP.NET Core MVC will recompile Razor files when the contents of a *.cshtml* file change.
Build-time compilation is supplemented by runtime compilation of Razor files. The <xref:Microsoft.AspNetCore.Mvc.Razor.RazorViewEngineOptions><xref:Microsoft.AspNetCore.Mvc.Razor.RazorViewEngineOptions.AllowRecompilingViewsOnFileChange> gets or sets a value that determines if Razor files (Razor views and Razor Pages) are recompiled and updated if files change on disk.
* If the app's compatibility version is set to <xref:Microsoft.AspNetCore.Mvc.CompatibilityVersion.Version_2_2> or later and the app is in the Development environment <xref:Microsoft.AspNetCore.Hosting.HostingEnvironmentExtensions.IsDevelopment*>. In other words, Razor files wouldn't recompile in non-Development environment unless <xref:Microsoft.AspNetCore.Mvc.Razor.RazorViewEngineOptions.AllowRecompilingViewsOnFileChange> is explicitly set.
1. Update the project's `Startup.ConfigureServices` method to include a call to `AddRazorRuntimeCompilation`. For example:
```csharp
public void ConfigureServices(IServiceCollection services)
{
services.AddRazorPages()
.AddRazorRuntimeCompilation();
// code omitted for brevity
}
```
### Conditionally enable runtime compilation
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.
To enable runtime compilation based on the environment and configuration mode:
1. Conditionally reference the [Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation](https://www.nuget.org/packages/Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation/) package based on the active `Configuration` value:
1. Update the project's `Startup.ConfigureServices` method to include a call to `AddRazorRuntimeCompilation`. Conditionally execute `AddRazorRuntimeCompilation` such that it only runs in Debug mode when the `ASPNETCORE_ENVIRONMENT` variable is set to `Development`:
```csharp
public IWebHostEnvironment Env { get; set; }
public void ConfigureServices(IServiceCollection services)
