Since .NET Core 3.0 your views in MVC won’t refresh after you change your .CSHTML markup. You can enable this for existing projects by installing Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation and setting AddRazorRuntimeCompilation() in your Startup.cs -> ConfigureServices method…
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for new projects you can check the ‘Enable Razor runtime compilation’ checkbox for 3.1 projects onwards when creating the projects.