disable precompiled views in .net core 2.1 and .net 5 for debugging?

.net core >= 3 (also called .net 5)

Microsoft created a Nuget Package. This is documented here.

Just reference Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation in your .csproj file conditionally. Don't forget to adjust the version, you actualy use.

<PackageReference

    Include="Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation"

    Version="3.1.0"

    Condition="'$(Configuration)' == 'Debug'" />

Also configure your services

    public void ConfigureServices(IServiceCollection services)

    {

        // your MVC Builder (AddRazorPages/AddControllersWithViews)

        IMvcBuilder builder = services.AddRazorPages();

#if DEBUG

            // Only use Runtime Compilation on Debug

            if (Env.IsDevelopment())

            {

                builder.AddRazorRuntimeCompilation();

            }

#endif

    }

Ofcourse, when you want to general use Runtime Compilation, even when published, you don't need all the conditions.

***********************

.net core >= 2.1 && < 3

This can be accomplished using the property RazorCompileOnBuild in the .csproj file:

<PropertyGroup>

  <TargetFramework>netcoreapp2.1</TargetFramework>

  <RazorCompileOnBuild>false</RazorCompileOnBuild>

  <RazorCompileOnPublish>true</RazorCompileOnPublish>

</PropertyGroup>

This way the Razor files are only precompiled during publishing.

Depending on the usecase you also want to configure this depending on the build configuration:

<PropertyGroup Condition="'$(Configuration)' == 'Debug'">

  <RazorCompileOnBuild>false</RazorCompileOnBuild>

  <RazorCompileOnPublish>true</RazorCompileOnPublish>

</PropertyGroup>