Well, yes you can. In earlier previews of Blazor, razor components used cshtml files, but this was replaced by razor files. There is an MSBuild property setting that enables you to use cshtml files, but it is purely intended for backward compatibility. There
is no benefit to using .cshtml files in a new Blazor app.
Are you trying to use Blazor UI C# in a n MVC layout page? If so, that's not supported. As I said in another of your threads, Blazor and MVC are not intended to be used together.
Well, yes you can. In earlier previews of Blazor, razor components used cshtml files, but this was replaced by razor files. There is an MSBuild property setting that enables you to use cshtml files, but it is purely intended for backward compatibility. There
is no benefit to using .cshtml files in a new Blazor app.