.NET Core MVC Page Not Refreshing After Changes - asp.net-core

Question

I'm building a .NET Core MVC on the latest version 2.2. I have a problem when I make changes to the CSHTML file and refresh the page, my changes are not reflected in the browser. I have to restart the project in order to see my changes. This has been happening for a while now so I'm not exactly sure what change caused this issue.
I've tried using the chrome's "Empty Cache and Hard Reload" as well as other browsers to no avail. This happens on Windows and Mac using both Visual Studio for Mac and VS Code
In a default .Net Core project it works fine so it must be something in my project that changed along the way. I'm wondering where I need to start in order to debug this issue? I've tried commenting out almost everything in my Startup.csand Program.cs with no resolution.

Answer 1

In ASP.NET Core 3.0 and higher, RazorViewEngineOptions.AllowRecompilingViewsOnFileChange is not available.
Surprised that refreshing a view while the app is running did not work, I discovered the following solution:
Add Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation NuGet package to the
project
Add the following in Startup.cs:
services.AddControllersWithViews().AddRazorRuntimeCompilation();
Here's the full explanation for the curious.

Answer 2

There was a change made in ASP.NET Core 2.2 it seems (and I can't find any announcements about this change). If you are not explicitly running in the 'Development' environment then the Razor Views are compiled and you will not see any changes made to the .cshtml
You can however turn off this using some config in your Startup class as follows.
services.AddMvc().AddRazorOptions(options => options.AllowRecompilingViewsOnFileChange = true);
For ASP.NET Core 3.0 and higher, see Alexander Christov's answer.

Answer 3

I've just created a new project using the latest ASP.NET MVC Core 3.1 template and I altered the following to get runtime recompilation enabled for Debug:
Reference NuGet package - Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation.
Startup.cs - ConfigureServices(IServiceCollection services) WAS:
// stuff...
services.AddControllersWithViews();
// more stuff...
NOW:
// stuff...
var mvcBuilder = services.AddControllersWithViews();
#if DEBUG
mvcBuilder.AddRazorRuntimeCompilation();
#endif
// more stuff...

Answer 4

In addition to Alexander Christov's answer, since ASP.NET Core 3.1 you can enable the view compilation for development environment without changes to the Startup file:
Install the Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation NuGet package.
Set next environment variables (for example via environmentVariables section in launchSettings.json):
ASPNETCORE_ENVIRONMENT to "Development".
ASPNETCORE_HOSTINGSTARTUPASSEMBLIES to "Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation".

Answer 5

You should just add this:
services.AddControllersWithViews();
to the ConfigureService method.
Be aware below code is not available in ASP.NET Core 3.1:
services.AddControllersWithViews().AddRazorRuntimeCompilation();

Answer 6

For those using Net core 3.0 or greater
Go to Tools → Nuget package manager → Manage nuget pakages for solution
move to browse tab to browse from internet
search for RuntimeCompilation
Click on Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation
install it on your intended projects the current stable version
open Startup.cs file
go to void method ConfigureServices
add line: services.AddControllersWithViews().AddRazorRuntimeCompilation();
you are DONE
Rerun and see. Now you can refresh your views or pages.

Answer 7

first of all install the Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation using nuget manager
after that add below code into your startup.cs
services.AddRazorPages().AddRazorRuntimeCompilation();
net6.0 also this works.
builder.Services.AddRazorPages().AddRazorRuntimeCompilation();

Answer 8

Using .net core 2.2 running app with command dotnet watch run the project is restarted after every change

Answer 9

Below helped me when views were in separate project.
if(HostingEnvironment.IsDevelopment()){ // only in development (optional)
services.AddMvc().AddRazorOptions(o => {
o.FileProviders.Add(new PhysicalFileProvider(PATH_TO_PROJECT));
});
}

Answer 10

I had the same issue while working on a .NET 6 MVC Web App.
I installed Microsoft.AspNetCore.Mvc.Razor.Runtime.Compilation from NuGet Package Manger then added .AddRazorRuntimeCompilation(); after
builder.services.AddControllersWithViews();
so that it looks like this
builder.services.AddControllersWithViews().AddRazorRuntimeCompilation();
and it worked!
Hope this helped.

Answer 11

I was able to solve this problem in Rider by adding the ASPNETCORE_ENVIRONMENT=Development environment variable.

Answer 12

There are two ways to resolve this issue:
1. Check the permissions of folder in which your .sln file present.There may be a problem with file access permissions as Visual studio may not be to access files when IIS express server is running, so to reflect new .cshtml changes each time you need to restart the server,so I suggest edit the folder access permissions by:
Right click on folder->properties->security->click on edit button -> check all options->save.
Restart Visual studio to see changes.
If this does not work then use 2 option.
2.In your project in startup.cs file add this below line ConfigureServices() in method :
services.AddMvc().AddRazorOptions(options => options.AllowRecompilingViewsOnFileChange = true);

Answer 13

Are you absolutely sure you are using 2.2? Check your csproj because it might be this bug https://github.com/aspnet/Razor/issues/2466
You could try turning off RazorCompileOnBuild more info https://learn.microsoft.com/en-us/aspnet/core/razor-pages/sdk?view=aspnetcore-2.1#properties

Answer 14

I had a similar problem upgrading from .net Core 3 to .net 5.0
Problem was due to old dependency in Telerik controls that we could not change.
Fixed by changing references in the .csproj file
<PackageReference Include="Microsoft.CodeAnalysis.Common" Version="3.8.0" />
to
<PackageReference Include="Microsoft.CodeAnalysis" Version="3.8.0" />
(your version may be different)

Answer 15

In Visual Studio 2022 Preview, it seems there is an option called Hot Reload for this purpose.
It seems to be available in Visual Studio 2019 too.
With Hot Reload you can now modify your apps managed source code while
the application is running, without the need to manually pause or hit
a breakpoint. Simply make a supported change while your app is running
and in our new Visual Studio experience use the “apply code changes”
button to apply your edits.
https://devblogs.microsoft.com/dotnet/introducing-net-hot-reload/