When I install Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation in a Web project and in Startup add :
services.AddMvc().AddRazorRuntimeCompilation();
,the project does not run and the error is:
the project must provide a value for configuration
my .NET-Core version is 3.1
How can this be fixed?
There are some GitHub issues with this problem and some solutions that have worked for people. That said I would check to see that all NuGet packages are on versions supported by .NET Core 3.1. At this particular moment that means not too new so as to only work with .NET 5 and not too old so as to only work with Core 2.2.
Otherwise, someone suggested restarting VS.
https://github.com/dotnet/sdk/issues/9932
You may also try deleting Microsoft.AspNetCore.Razor.Design from the CsProj file per this duplicate question