Skip to content

Update the weather page in the Blazor Web App template to persist prerendered state #64644

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom
Open
Copilot wants to merge 2 commits into
base: main
Choose a base branch
from
Open

Update the weather page in the Blazor Web App template to persist prerendered state #64644

Copilot wants to merge 2 commits into from
+19 −15

Conversation

Copy link
Contributor

Copilot AI commented Dec 3, 2025 •
edited
Loading

Update the weather page in the Blazor Web App template to persist prerendered state

  • You've read the Contributor Guide and Code of Conduct.
  • You've included unit or integration tests for your change, where applicable.
  • You've included inline docs for your change, where applicable.
  • There's an open issue for the PR that you are making. If you'd like to propose a new feature or change, please open an issue to discuss the change or find an existing issue.

Use [PersistentState] attribute in Weather.razor to avoid "Loading..." flash on direct navigation

Description

When navigating directly to the weather page in an interactive Blazor Web App, users see the prerendered content, then a flash of "Loading...", then the data again. This is particularly noticeable due to the 500ms simulated delay.

The fix uses [PersistentState] to persist the prerendered forecasts and restore them when interactive mode starts:

  • Add [PersistentState] attribute to Forecasts property
  • Change from private field to public property (required for attribute)
  • Make WeatherForecast class public (required for JSON serialization)
  • Skip data loading in OnInitializedAsync when state is already restored
@code {
    [PersistentState]
    public WeatherForecast[]? Forecasts { get; set; }

    protected override async Task OnInitializedAsync()
    {
        if (Forecasts is null)
        {
            await Task.Delay(500);
            // ... load forecasts
        }
    }

    public class WeatherForecast { ... }
}
Original prompt

This section details on the original issue you should resolve

<issue_title>Update the weather page in the Blazor Web App template to persist prerendered state</issue_title>
<issue_description>The weather page in the Blazor Web App template doesn't currently persist its prerendered state. This means that if the weather page is rendered interactively and you browse directly to the weather page, you'll see the weather prerendered, then replaced with Loading..., and then rendered again. The flash is particularly visible because we include the Task.Delay(500) to simulate loading the weather data.

</issue_description>

Comments on the Issue (you are @copilot in this section)

@ Thanks for contacting us.

We're moving this issue to the .NET 9 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.</comment_new>
<comment_new>@
Thanks for contacting us.

We're moving this issue to the .NET 9 Planning milestone for future evaluation / consideration. We would like to keep this around to collect more feedback, which can help us with prioritizing this work. We will re-evaluate this issue, during our next planning meeting(s).
If we later determine, that the issue has no community involvement, or it's very rare and low-impact issue, we will close it - so that the team can focus on more important and high impact issues.
To learn more about what to expect next and how this issue will be handled you can read more about our triage process here.</comment_new>

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

Copilot AI changed the title [WIP] Update weather page to persist prerendered state Update the weather page in the Blazor Web App template to persist prerendered state Dec 3, 2025
Copilot AI requested a review from javiercn December 3, 2025 23:40
@javiercn javiercn marked this pull request as ready for review December 4, 2025 09:38
Copilot AI review requested due to automatic review settings December 4, 2025 09:38
Copilot AI reviewed Dec 4, 2025
View reviewed changes
Copy link
Contributor

Copilot AI left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Pull request overview

This PR updates the Weather page in the Blazor Web App template to use the [PersistentState] attribute, which eliminates the "Loading..." flash that occurs when directly navigating to the weather page. The feature works by persisting the prerendered weather forecast data and restoring it when the component becomes interactive, avoiding the need to reload the data and display the loading indicator.

Key Changes:

  • Applied [PersistentState] attribute to persist weather forecast data across prerendering
  • Converted private field to public property (required for state persistence)
  • Made WeatherForecast class public (required for JSON serialization)

@dotnet-policy-service
Copy link
Contributor

dotnet-policy-service bot commented Dec 11, 2025

Looks like this PR hasn't been active for some time and the codebase could have been changed in the meantime.
To make sure no conflicting changes have occurred, please rerun validation before merging. You can do this by leaving an /azp run comment here (requires commit rights), or by simply closing and reopening.

@dotnet-policy-service dotnet-policy-service bot added the pending-ci-rerun When assigned to a PR indicates that the CI checks should be rerun label Dec 11, 2025
@javiercn
Copy link
Member

javiercn commented Dec 17, 2025

/azp run aspnetcore-template-tests-pr, aspnetcore-ci

@azure-pipelines
Copy link

azure-pipelines bot commented Dec 17, 2025

Azure Pipelines successfully started running 2 pipeline(s).

@build-analysis build-analysis bot mentioned this pull request Dec 17, 2025
Open
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Reviewers

Copilot code review Copilot Copilot left review comments

@javiercn javiercn Awaiting requested review from javiercn

At least 1 approving review is required to merge this pull request.

Assignees

@javiercn javiercn

Copilot code review Copilot

Labels

Attention: Shared Code Modified pending-ci-rerun When assigned to a PR indicates that the CI checks should be rerun

Projects

None yet

Milestone

No milestone

Development

Successfully merging this pull request may close these issues.

Update the weather page in the Blazor Web App template to persist prerendered state

2 participants

@javiercn