Provide a way to persist prerendered state when using Blazor server-side rendering

[danroth27]

We provide a persist-component-state tag helper for persisting state used during prerendering from an MVC view or Razor Page. We need a way to persist the component state from a Blazor component when using server-side rendering (SSR).

[Alerinos]

@danroth27
This is quite problematic, for example if we want to transport cookies then we have to go through "Component"
Example:

    <component type="typeof(Areas.Web.App)"
               render-mode="ServerPrerendered"
               param-GetIP="@GetIP"
               param-GetAgent="@GetAgent"
               param-GetCookies="@GetCookies"
               param-SessionUser=@SessionStat.User />

If this is not done, we have this effect.
The first reload (server) is correct, the second reload causes the Scope circuit to disappear.
https://gyazo.com/dcae15aebf6269f1023a8f185920a9e1

---

edit:
If we do away with _host.cshtml and there is no longer a <component>, how can we pass parameters to the Blazor circuit?

[oliverw]

So how is this now actually done from an application perspective?

[marinasundstrom]

@oliverw It's documented here:

https://learn.microsoft.com/en-us/aspnet/core/blazor/components/prerendering-and-integration?view=aspnetcore-7.0&pivots=webassembly#persist-prerendered-state

[oliverw]

@oliverw It's documented here:

https://learn.microsoft.com/en-us/aspnet/core/blazor/components/prerendering-and-integration?view=aspnetcore-7.0&pivots=webassembly#persist-prerendered-state

Thanks. Not sure if that has been updated for Blazor 8 Web Apps. I don't have a .cshtml file.

[marinasundstrom]

@oliverw Woops. Sorry. It was the wrong link: https://learn.microsoft.com/en-us/aspnet/core/blazor/components/prerender?view=aspnetcore-8.0#persist-prerendered-state

I thought it switched over to the .NET 8 version when I selected it. But it is not the same document.

But basically, it is the same. Just no need for a the tag helper anymore.

[oliverw]

@oliverw It's documented here:

https://learn.microsoft.com/en-us/aspnet/core/blazor/components/prerendering-and-integration?view=aspnetcore-7.0&pivots=webassembly#persist-prerendered-state

Thanks again. Is that supposed to work with @rendermode InteractiveAuto ?

[marinasundstrom]

@oliverw Yes. Since it works with both InteractiveServer and InteractiveWebAssembly when components are prerendered.

[oliverw]

@oliverw Yes. Since it works with both InteractiveServer and InteractiveWebAssembly when components are prerendered.

Cool. Trying it out 😄

[marinasundstrom]

@oliverw 👍🏻 🙂 If you want an example, then there is this: https://github.com/marinasundstrom/Blazor8Test/blob/main/src/Client/Pages/FetchData.razor