Provide a pattern for initialization code in Blazor WASM

[klemmchr]

When developing a library for ASP.NET Core that needs to use IApplicationBuilder I can reference Microsoft.AspNetCore.Http.Abstractions.

When I want to use IComponentsApplicationBuilder I need to add an reference to Microsoft.AspNetCore.Blazor which not just contains the abstractions.

Having an abstraction package for Blazor like Microsoft.AspNetCore.Blazor.Abstractions would allow to just reference the abstractions instead of needing to add a reference to blazor itself.

[javiercn]

@Chris579 Thanks for contacting us.

Can you give us more details on why is it problematic to reference Microsoft.AspNetCore.Blazor and what you are trying to accomplish?

This is an area that is likely to change in the future. What functionality of IComponentsApplicationBuilder are you trying to get access to?

[klemmchr]

I find it inconvenient to reference Blazor as a whole (especially because it will heavily change in the future). When there are new Blazor versions introducing breaking changes (that are not affecting my library) I would need to update my package even though it does not make use of Blazor at all. Plus, if creating a library that does target both Blazor and Blazor Serverside I would need to reference Blazor as a whole too. That means that if somebody uses Blazor Serverside and installs my library he will also install blazor, no matter if he even uses it.

[rynowak]

Plus, if creating a library that does target both Blazor and Blazor Serverside I would need to reference Blazor as a whole too.

Our recommendation would be to reference Microsoft.AspNetCore.Components and Microsoft.AspNetCore.Components.Web if you're building a library. Can you be specific about what else you need?

[klemmchr]

IComponentsApplicationBuilder is neither part of Microsoft.AspNetCore.Components nor Microsoft.AspNetCore.Components.Web.

[rynowak]

I think we need to know a little bit more about what you're doing then. Using IComponentApplicationBuilder isn't something I anticipated from a library. Is there a publicly accessible link I can look at?

[klemmchr]

I removed the relevant code from my library some days ago because I restructured it a bit. However, this kind of describes what I did:

public class MyInitService
{
    public void DoInit() {}
}

public class Startup
{
    public void ConfigureServices(IServiceCollection services)
    {
        services.AddTransient<MyInitService>();
    }

    public void Configure(IComponentsApplicationBuilder app)
    {
        app.UseInit();
        app.AddComponent<App>("app");
    }
}

public static class ComponentApplicationBuilderExtensions
{
    public static IComponentsApplicationBuilder UseInit(this IComponentsApplicationBuilder componentsApplicationBuilder)
    {
        componentsApplicationBuilder.Services.GetRequiredService<MyInitService>().DoInit();

        return componentsApplicationBuilder;
    }
}

For me, the purpose of the Configure method is similar to the one from AspNetCore server.

[rynowak]

Thanks @Chris579 - we'll look for a solution to this kind of thing as part of the client release.

[mkArtakMSFT]

We will tackle this as part of #16874