MvcRazorPagesMvcBuilderExtensions

/// <summary>
/// Configures Razor Pages to be rooted at the content root (<see cref="IHostingEnvironment.ContentRootPath"/>).
/// </summary>
/// <param name="builder">The <see cref="IMvcCoreBuilder"/>.</param>
/// <returns>The <see cref="IMvcBuilder"/>.</returns>
public static IMvcBuilder WithRazorPagesAtContentRoot(this IMvcBuilder builder)
{
    if (builder == null)
    {
        throw new ArgumentNullException(nameof(builder));
    }

    builder.Services.Configure<RazorPagesOptions>(options => options.RootDirectory = "/");
    return builder;
}