Does Blazor Server 7 need to call MapRazorPages()?

Question

When Visual Studio creates a Blazor server app, there's no call to app.MapRazorPages() in Program.cs

But I do see that call in a lot of examples. Is that something that used to be needed? Or should it be added back in?

I am using Asp.Net Core 7, Blazor server side.

thanks - dave

Answer 1

Hi,@David Thielen,

all your razor components were rendered on _Host.cshtml by default

the document related

• _Host.cshtml: The root page of the app implemented as a Razor Page:
• When any page of the app is initially requested, this page is rendered and returned in the response.
• The Host page specifies where the root App component (App.razor) is rendered.

And app.MapFallbackToPage("/_Host"); is required to map different paths to _Host.cshtml

Then ,you could check the source codes here

public static PageActionEndpointConventionBuilder MapRazorPages(this IEndpointRouteBuilder endpoints)
    {
        ArgumentNullException.ThrowIfNull(endpoints);
        EnsureRazorPagesServices(endpoints);
        return GetOrCreateDataSource(endpoints).DefaultBuilder;
    }


public static IEndpointConventionBuilder MapFallbackToPage(this IEndpointRouteBuilder endpoints, string page)
    {
        ArgumentNullException.ThrowIfNull(endpoints);
        ArgumentNullException.ThrowIfNull(page);

        PageConventionCollection.EnsureValidPageName(page, nameof(page));

        EnsureRazorPagesServices(endpoints);

        // Called for side-effect to make sure that the data source is registered.
        var pageDataSource = GetOrCreateDataSource(endpoints);
        pageDataSource.CreateInertEndpoints = true;
        RegisterInCache(endpoints.ServiceProvider, pageDataSource);

        // Maps a fallback endpoint with an empty delegate. This is OK because
        // we don't expect the delegate to run.
        var builder = endpoints.MapFallback(context => Task.CompletedTask);
        builder.Add(b =>
        {
            // MVC registers a policy that looks for this metadata.
            b.Metadata.Add(CreateDynamicPageMetadata(page, area: null));
            b.Metadata.Add(new PageEndpointDataSourceIdMetadata(pageDataSource.DataSourceId));
        });
        return builder;
    }

The two extension methods both call EnsureRazorPagesServices(endpoints); to handle razor page endpoints.

So you could visit razor page endpoints in default Blazor Server project even if app.MapRazorPages() is not called

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Answer 2

You only need it if your site includes razor pages, say you use the identity package or add your own razor pages.