[10.0] [Blazor] Support NavigateTo when enhanced nav is disabled (#52267)

[javiercn]

[10.0] [Blazor] Support NavigateTo when enhanced nav is disabled (#52267)

Makes the NavigateTo API work even if enhanced nav is disabled via config.

Description

By default, Blazor apps have either enhanced nav or an interactive router. In these default cases, the NavigateTo API works correctly.

However there's also an obscure way to disable both of these via config. It's niche, but it's supported, so the rest of the system should work with that. Unfortunately NavigateTo assumes that either enhanced nav or an interactive router will be enabled and doesn't account for the case when neither is.

Fixes #51636

Customer Impact

Without this fix, anyone who uses the ssr: { disableDomPreservation: true } config option will be unable to use the NavigateTo API, as it will do nothing. This behavior isn't desirable.

Regression?

• Yes
• No

No because existing code can't use ssr: { disableDomPreservation: true } as the option didn't exist prior to .NET 8.

Someone else might argue that it's a regression in the sense that, if you're migrating existing code to use newer .NET 8 patterns (and are using disableDomPreservation for some reason, even though you wouldn't normally), your existing uses of NavigateTo could stop working. That's not how we normally define "regression" but I'm trying to give the fullest explanation.

Risk

• High
• Medium
• Low

The fix explicitly retains the old code path if you're coming from .NET 7 or earlier (i.e., if you are using blazor.webassembly/server/webview.js. The fixed code path is only applied in blazor.web.js, so it should not affect existing apps that are simply moving to the net8.0 TFM without other code changes.

Verification

• Manual (required)
• Automated

Packaging changes reviewed?

• Yes
• No
• N/A

---

When servicing release/10.0

• Make necessary changes in eng/PatchConfig.props

[Copilot]

Pull request overview

This PR fixes a bug where the NavigateTo API fails to work when enhanced navigation is disabled via the ssr: { disableDomPreservation: true } configuration option. The fix introduces a new isBlazorWeb flag to differentiate between blazor.web.js and the older blazor.server.js/blazor.webassembly.js hosting models, allowing blazor.web.js to perform a full page load in scenarios where neither enhanced navigation nor an interactive router is available.

Key Changes:

• Refactored navigation logic to explicitly handle three page load mechanisms: client-side router, server-side enhanced navigation, and server-side full page load
• Added isBlazorWeb flag to distinguish blazor.web.js from legacy hosting models for backward compatibility
• Added comprehensive E2E tests covering all combinations of enhanced navigation and force load scenarios

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
src/Components/Web.JS/src/Services/NavigationManager.ts	Refactored navigateToCore to explicitly handle three page load mechanisms; added currentPageLoadMechanism function to determine navigation strategy based on router availability and hosting model
src/Components/Web.JS/src/GlobalExports.ts	Added optional isBlazorWeb property to the IBlazor._internal interface to identify blazor.web.js hosting model
src/Components/Web.JS/src/Boot.Web.ts	Set Blazor._internal.isBlazorWeb = true during boot to identify blazor.web.js context
src/Components/test/E2ETest/Infrastructure/WebDriverExtensions/WebDriverExtensions.cs	Added IsStale extension method to check if WebElement references are stale after navigation
src/Components/test/testassets/Components.TestServer/RazorComponents/Pages/Interactivity/InteractiveNavigateTo.razor	New test component to verify NavigateTo functionality with buttons for normal and force-load navigation
src/Components/test/E2ETest/ServerRenderingTests/InteractivityTest.cs	Added parameterized test covering 4 scenarios for NavigateTo with/without enhanced navigation and force load
src/Components/test/testassets/Components.TestServer/RazorComponents/Shared/EnhancedNavLayout.razor	Wrapped @Body in semantic <main> element for improved HTML structure in test layout