Bug 51681 - Previewer shows an error over the preview of a valid view
Summary: Previewer shows an error over the preview of a valid view
Alias: None
Product: Visual Studio Extensions
Classification: Xamarin
Component: Xamarin.Forms Previewer ()
Version: 4.6.0 (15.3)
Hardware: PC Windows
: --- normal
Target Milestone: ---
Assignee: Bugzilla
Depends on:
Reported: 2017-01-21 00:04 UTC by David Ortinau [MSFT]
Modified: 2017-07-10 20:36 UTC (History)
4 users (show)

Tags: ac vs vsmac
Is this bug a regression?: ---
Last known good build:

environment notes (2.57 KB, text/plain)
2017-01-21 00:04 UTC, David Ortinau [MSFT]
project (6.51 MB, application/x-zip-compressed)
2017-01-21 00:21 UTC, David Ortinau [MSFT]

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Description David Ortinau [MSFT] 2017-01-21 00:04:46 UTC
Created attachment 19425 [details]
environment notes

I have 2 xaml files, one valid that renders fine and another that has an error. When I change from the valid file to the bad file, the error appears however the preview does not change and the error visually is related to the valid file.

I would expect the preview to return to the grey initializing state and not retain the old, valid layout. Then display the error over the default state.
Comment 1 David Ortinau [MSFT] 2017-01-21 00:21:56 UTC
Created attachment 19429 [details]
Comment 2 Pierce Boggan [MSFT] 2017-06-20 20:29:29 UTC
Thanks for filing this @David! I was able to reproduce this issue using the latest d15-3 internal builds.

When switching from one view to another, if there is an issue in syntax, the last "good" preview is shown, rather than an error for the page you are currently on:

Environment Information: https://gist.github.com/pierceboggan/f1ffd9e92b04565eb494d4138e1a034a
Comment 3 Alan McGovern 2017-06-26 10:01:54 UTC
This is supposed to be addressed by swapping to use a proper split view for the previewer instead of the toolwindow.

I have no idea of the ETA on that though.
Comment 4 Jimmy [MSFT] 2017-07-10 20:36:13 UTC
I can still reproduce this with the latest VS 2017 15.3 and VS4Mac previews. Updating report accordingly.

The behavior on VS4Mac is slightly different in that the previously valid page is still displayed but with an error and that error persists while previewing the other valid pages.