Repository navigation
[Bug]: Avalonia VS previewer no longer sees my configured previewer host project #200
Description
Describe the bug
We have multiple projects for which the real BuildAvaloniaApp entry point cannot be used for the Avalonia VS Previewer. The reasons are things such as the project being a plugin for another application or being an OS service, so nothing which can be changed.
For these projects we have set up supporting test projects which mock dependencies and generally alter the setup of the Avalonia application to create something which can load our views in both the Avalonia VS Previewer and our unit tests.
These projects no longer appear in the VS Previewer's project select combo box. This is probably related to the change "Smarter previewer project selection and remembering" in version 12.3.0 of the VS Extension. This issue prevents us from using the previewer at all.
The projects which do appear can be class libraries or console applications, so this doesn't seem to be the problem. Is the new logic specifically excluding test projects?
To Reproduce
Unknown
Product(s)
Avalonia for Visual Studio
Platform
Windows
License Tier
Pro
Avalonia version
12.1.2
Tool/Control Version
12.3.1.0
Relevant log output
Additional context
No response
Activity
mrlacey commentedon Sep 30, 2026
on it.
mrlacey commentedon Sep 30, 2026
I'm testing a hotfix release for this with a view to releasing it tomorrow.
mrlacey commentedon Oct 1, 2026
Version 12.3.2 is now in the marketplace and includes a fix that addresses this issue.
If you find you still have issues, please let us know.
Sorry again that you had this problem. The change that caused this was intended to help those who were seeing lots of entries in the list that were inappropriate. We were obviously a bit too enthusiastic in what was filtered out.
TomEdwardsEnscape commentedon Oct 1, 2026
Thank you for the quick response, the previewer now works again.
Alongside the test project containing our special AppBuilder, the change reintroduces quite a lot of other test projects to the list which shouldn't be there because they always fail with this error:
These ones can definitely be removed.