[Blazor .NET 8] The same component instance rendered in different pages when using interactive mode

[gaplin]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

When on a static page I include interactive component in the same place then when moving from one page to the other, the same instance is rendered.
I've included simple repro including timer component.
Here is a video showing current behaviour (counter value should be reset between pages):

timer.mp4

Problem is solved either by:

• Using @key attribute directly on components
• Adding empty component before interactive one on either counter or home page.
• Using InteractiveMode directly on page

I think it might be related to this open issue #51073

Expected Behavior

Rendered instances are different

Steps To Reproduce

1. Clone https://github.com/gaplin/TimerRepro
2. Run the app
3. Move between pages using nav menu

Exceptions (if any)

No response

.NET Version

8.0.100

Anything else?

No response

[javiercn]

@gaplin thanks for contacting us.

That behavior is expected and by design. We will preserve existing interactive components when they are present on the new page, otherwise the components will lose their state, which we don't think its desirable.

[gaplin]

For above use case (showing how much time user spent on given page) it is desirable to have different instances.

It's pretty hard to run into this issue since both components need to have the same parameters and be placed in the same place on different pages.

For me it seems kind of odd since such behaviour adds hidden dependency on other pages.

[mkArtakMSFT]

We're going to close this for now, given this was an intentional design choice we've made during development, as well as there are ways to work around this behavior. We will, however, keep an eye to see if others will run into this issue too in the future, and if we find that too many customers find this behavior unexpected, we will revisit the design decision.

[mkArtakMSFT]

Ok, we've changed our mind about this. Let's keep it open to accumulate more feedback.

[mkArtakMSFT]

And looks like we have an existing issue tracking this already: #51073