Grid RowDefinitions/ColumnDefinitions not recognized by VS2022

[asklar]

Describe the bug

1st problem is that VS doesn't understand what RowDefinitions (or ColumnDefinitions) means and shows a squiggly - even though it works at runtime

Steps to reproduce the bug

<Grid RowDefinitions="123,*">
...
</Grid>

Expected behavior

Screenshots

NuGet package version

WinUI 3 - Windows App SDK 1.0 (If you're seeing your issue in older previews of WinUI 3, please try this release)

Windows app type

• UWP
• Win32

Device form factor

Windows version

Insider Build (xxxxx)

Additional context

No response

[StephenLPeters]

@evelynwu-msft FYI

[HEIC-to-JPEG-Dev]

This means that there is effectively no visual editor for WinUI if you use this XAML as VS doesn't have one, and live edit doesn't work as it doesn't recognise the XAML if any part is modified.

[evelynwu-msft]

Sort of related to #5944.

[ettiennehugo]

Just FYI, I did get this issue and it is actually due to something else broken in your XAML. To fix it, define the RowDefinitions attribute using the Grid.RowDefinitions/RowDefinition tags - fixing this "error" will expose the other error in your XAML. Once the other error is fixed you can revert to using the RowDefinitions attribute.

This is still an issue though with the XAML parser highligting the wrong error.

[HEIC-to-JPEG-Dev]

Just FYI, I did get this issue and it is actually due to something else broken in your XAML. To fix it, define the RowDefinitions attribute using the Grid.RowDefinitions/RowDefinition tags - fixing this "error" will expose the other error in your XAML. Once the other error is fixed you can revert to using the RowDefinitions attribute.

This is still an issue though with the XAML parser highligting the wrong error.

I disagree. The XAML works perfectly and there are no errors. Making a simple change, like adding a space or changing a value causes this error. Using the long-form XAML and making the same change does not cause this (or any other) error. Therefore the live XAML editor is at fault and needs to be fixed - what's the point of a live XAML editor that doesn't work (unless you replace simple XMAL with lots of lines of XAML; can you imaging saying that to C# & .Net 8 - "Oh yes a the feature to remove 10 lines of boilerplate code is amazing, but if you use it, the IDE will show errors until you re-compile & run the app")