Consider using C#9 Source Generators for implementing SetParametersAsync

[ChristianWeyer]

The performance best practices here talk about a custom implementation of SetParametersAsync instead of using reflection:
https://docs.microsoft.com/en-us/aspnet/core/blazor/webassembly-performance-best-practices?view=aspnetcore-5.0#implement-setparametersasync-manually

@stefanloerwald has built a lib that uses C#9 source generators that shows significant perf improvements:
https://github.com/excubo-ag/Generators.Blazor

Could that be an approach to include into the Blazor framework?

[stefanloerwald]

Thanks for the flowers @ChristianWeyer. Just for the record: the perf improvement I measured was in a very narrow benchmark, which doesn't fully reflect the performance improvement in the context of the entire blazor framework.
That said, I think a lot can be done with source generators. Given that there is the idea out there to rewrite the razor compiler using source generators, there's a good opportunity to integrate such things by default.

[javiercn]

@ChristianWeyer thanks for contacting us.

We looked at this as part of 5.0. It does improve perf a bit (@SteveSandersonMS has the data) but we didn't see any significant improvement and there were a few things we were concerned about, which is why we didn't do it.

• It comes at the risk of introducing behavior changes over the stock implementation.
• It introduces servicing issues (what happens if there's a security issue in the generated code).
• We didn't have a way in the Razor compiler to do this in a reasonable way. (Since we couldn't know when a component was overriding SetParametersAsync in component base).

/cc: @SteveSandersonMS am I missing something here?

Thanks for contacting us.
We're moving this issue to the Next sprint planning milestone for future evaluation / consideration. We will evaluate the request when we are planning the work for the next milestone. To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.