[WASM] ... no longer builds using latest DEV bits

[DierkDroth]

Current behavior

I'm not sure if caused by #12755 or not, but upgrading to latest DEV bits (see screenshot below) prevents my solution from building throwing these errors

9>C:\tmp\unusual-src-dev\Unusual.Wasm\Uno.UI.SourceGenerators\Uno.UI.SourceGenerators.XamlGenerator.XamlCodeGenerator\MaterialTheme_84d781f597680f94b23c291ff1c40a24.cs(1190,14,1190,108): error CS1029: #error: 'Property for DropDownPreferredPlacement cannot be found on Microsoft.UI.Xaml.Controls.ComboBox'
9>C:\tmp\unusual-src-dev\Unusual.Wasm\Uno.UI.SourceGenerators\Uno.UI.SourceGenerators.XamlGenerator.XamlCodeGenerator\MaterialTheme_84d781f597680f94b23c291ff1c40a24.cs(6125,15,6125,119): error CS1029: #error: 'Property for ShouldFallBackToNativeScrollBars cannot be found on Microsoft.UI.Xaml.Controls.ScrollViewer'

@TopProgrammer77 @dr1rrb FYI

Update:
After further investigation I found that the culprit are these lines in my MaterialTheme.xaml style file:

<not_win:Setter Property="(uno:ScrollViewer.ShouldFallBackToNativeScrollBars)" Value="False" />
<xamarin:Setter Property="uno:ComboBox.DropDownPreferredPlacement" Value="Below" />												

That file is a copy&paste from UNO Material theme sources ~1.5 years back + some heavy customization I applied meanwhile. However, the 2 lines above had been part of the original UNO Material theme source.

I needed to know if I could savely remove those lines of if should replace them by something different. Note: I'm only using the WindowsAppSDK and the WASM head at this time.

[jeromelaban]

Thanks for the report.

The master of Uno is now updated to the upcoming Uno 5 release, which contains some breaking changes that are currently being documented here. Libraries such as uno.material have been updated as well to handle those changes.

[DierkDroth]

Thanks @jeromelaban

I checked the link you provided and could not find any reference for neither ShouldFallBackToNativeScrollBars nor DropDownPreferredPlacement. What am I missing?

[jeromelaban]

The default styles present in Uno.Themes are working properly with those lines and should be working properly with your app as well. We do not have a modification suggestion at this time.

[DierkDroth]

@jeromelaban I'm confused. Are you saying the current Uno.Themes sources would hold those lines and still compile/build using the 'latest' bits which I tried to apply?

If so, what should I then be looking at in order to make my project compilable again?

[jeromelaban]

Yes, the latest uno.theme dev bits have those two lines and builds properly. As I mentioned, if your project does not build, we do not have an upgrade path yet. You can open an issue with a repro sample that shows what's not building.

[DierkDroth]

I did some digging and still don't know what would cause that.

• as for DropDownPreferredPlacement at least I needed to add a new package (UNO.WinUI) which was not needed in my solution until now ... I don't want to do that for just fixing a detail which what was working so far
• as for ShouldFallBackToNativeScrollBars I would not know where to begin with

I just removed both lines from my MaterialThemes.xaml. Appears this has no negative impact on ComboBox nor CalenderView (where they had been consumed).