Reconnect UI component

[guardrex]

Fixes #34813

Notes

• I'm versioning all of the 10.0 or later content into one moniker range, and I'm disabling all of the existing content for <10.0. In the past, I broke up coverage into multiple moniker ranges because parts of the coverage changed (e.g., filenames, file locations).
• I'm using our standard approach for cross-linking reference source. I link the main branch, and I include the guidance on selecting the correct release branch/tag.

❓Questions❓

• Are the existing images still accurate? If not, I'll make a tracking note to snap and place new shots on Preview 2 release day because I'm not on nightly releases (yet anyway 😄).
  • https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/blazor/fundamentals/signalr/_static/reconnection-ui-90-or-later.png
  • https://github.com/dotnet/AspNetCore.Docs/blob/main/aspnetcore/blazor/fundamentals/signalr/_static/retry-ui-90-or-later.png
• The rejected scenario is a bit confusing: What does the ReconnectModel component display in that scenario? There's no such class (element marked with) "components-reconnect-rejected-visible," and doesn't components-reconnect-failed-visible go to display: none on a rejection? I don't see any styles for components-reconnect-rejected when it's applied to the dialog.
• Are there any gotchas 😈 to call out?

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Internal previews

📄 File	🔗 Preview link
aspnetcore/blazor/fundamentals/signalr.md	aspnetcore/blazor/fundamentals/signalr

[oroztocil]

Sorry for keeping you waiting for the review. I first want to investigate and fix https://github.com/dotnet/AspNetCore-ManualTests/issues/3489 because it might involve changing some things mentioned in the docs.

[guardrex]

Thanks @oroztocil ... I'll work on this now and ping you back on the next commit.

[guardrex]

@oroztocil ... I retained the table, collapsed some of duplicate coverage a bit for the event, but I also split out the extended explanations to paragraphs under the table. I moved the ReconnectModal coverage to the end and rephrased the lead-in remarks to it. It's ready for another 👁️.

[guardrex]

... and @oroztocil ... see my questions in my OP ☝️. The first question is important on retaining the current images. The second question might not be something that we need in the coverage ... it could just be something simple that I don't understand.

[oroztocil]

@guardrex To answer your questions:

• Yes, the images should still be accurate. The component reuses styles from the previous default solution.
• On the rejected state event, the component calls location.reload which means the browser reloads the page. After the reload, the application is either displayed normally (if it reconnects to the Blazor server successfully), or the reconnection UI shows up again and goes through the various states again from start.
• None come to mind at the moment. But I'll reach out to you if we find some based on user feedback.

[guardrex]

On the rejected state event, the component calls location.reload which means the browser reloads the page. After the reload, the application is either displayed normally (if it reconnects to the Blazor server successfully), or the reconnection UI shows up again and goes through the various states again from start.

I see ... yeah ... I think that's logical from reading the code. You can let me know if you think we should have remark about it at the end of the section.

[guardrex]

@oroztocil ... Is this getting better or WORSE? 😆

It looks like we should show example code for wiring up the event, so I added a simplified example.

Also, note that I did state the default for the .NET CLI ...

--interactivity server (default)

... but not for VS because IIRC 🤔 VS remembers the last app setup ... so Server/Auto isn't really a "default" for VS IIRC. Let me know if I'm wrong about that.

[oroztocil]

I think it's good now 🙂 I'd say this piece of functionality is inherently a bit difficult to document. (And I guess I should have written some summary of how the entire thing works to make it less confusing from the start.)

[guardrex]

No worries ... that's ok. It perhaps saved a little of your time for me to take a stab at it and just fix my poor guesses 🙈😄.