XAML Object Self Reference Gets Warning

[david-maw]

Description

With MauiEnableXamlCBindingWithSourceCompilation set, objects that self-refer get warning

XamlC warning XC0045: Binding: Property "property name" not found

For example, this XAML (which draws a circle of diameter MainViewModel.Diameter

            <Ellipse Stroke="Red"
                 Fill="White"
                 StrokeThickness="5"
                 WidthRequest="{Binding Diameter}"
                 HeightRequest="{Binding Source={RelativeSource Self},Path=WidthRequest}"
                 HorizontalOptions="Center"
                 VerticalOptions="End"
                 Margin="20"/>

gets the warning

XamlC warning XC0045: Binding: Property "WidthRequest" not found

Because Widthrequest is a property of the Ellipse class whereas Diameter is a property of the MainViewModel class which is specified in an enclosing page level x:DataType.

Steps to Reproduce

1. Open the project from Git
2. Build It
3. Observe The Warning

Link to public reproduction project repository

https://github.com/david-maw/ItemSelfRef.git

Version with bug

9.0.0-rc.2.24503.2

Is this a regression from previous behavior?

Not sure, did not test other versions

Last version that worked well

No response

Affected platforms

I was not able test on other platforms

Affected platform versions

No response

Did you find any workaround?

No response

Relevant log output

No response

[similar-issues-ai]

We've found some similar issues:

• XAML Page Binding to Self Gets Incorrect Warning #25271 , similarity score: 83%

If any of the above are duplicates, please consider closing this issue out and adding additional context in the original issue.

Note: You can give me feedback by 👍 or 👎 this comment.

[jaosnz-rep]

I can repro this issue at Windows platform on the latest 17.12.0 Preview 2.1(9.0.0-rc.2.24503.2 & 9.0.0-rc.1.24453.9).

[simonrozsival]

@david-maw in this case, the best way to do this is to specify the x:DataType directly on the {Binding} like this:

HeightRequest="{Binding Source={RelativeSource Self}, Path=WidthRequest, x:DataType=Ellipse}"

Does this solve your issue?

[StephaneDelcroix]

very similar to #25271

[david-maw]

I had not realized you could even do that, and VS autocomplete doesn't offer it yet!
I'll be a bit tedious to do, but I can do it, and until #21834 can be implemented, it'll do, thanks.