AttachedProperty setter is not called in XAML when named Uid

[AndrewKeepCoding]

Current behavior

As it's mentioned in the title, AttachedProperty setter is not called in XAML when named Uid
This happens on:

• Android
• WASM
• Desktop
• MacOS

It works as expected

• on WASDK
• the AttachedProperty has other name
• the setter is called on C# code

For example:

Uids.cs

public static class Uids
{
    public static readonly DependencyProperty UidProperty =
        DependencyProperty.RegisterAttached(
            "Uid",
            typeof(string),
            typeof(Uids),
            new PropertyMetadata(default));

    public static string GetUid(DependencyObject obj) => (string)obj.GetValue(UidProperty);

    public static void SetUid(DependencyObject obj, string value) => obj.SetValue(UidProperty, value);
}

MainPage.xaml

<Button
    x:Name="GoToSecondButton"
    AutomationProperties.AutomationId="SecondPageButton"
    local:Uids.Uid="ButtonUid"
    Command="{Binding GoToSecond}"
    Content="Go to Second Page" />

MainPage.xaml.cs

private void MainPage_Loaded(object sender, RoutedEventArgs e)
{
    var buttonUid = Uids.GetUid(GoToSecondButton);
    // butonUid is null.
    GoToSecondButton.Content = buttonUid;
}

Expected behavior

The AttatchedProperty setter should be called even if it's name is Uid.

How to reproduce it (as minimally and precisely as possible)

Here is a reproducible repo:
https://github.com/AndrewKeepCoding/UnoPlatformAttatchedPropertyDemo

Workaround

No response

Works on UWP/WinUI

Yes

Environment

No response

NuGet package version(s)

Uno.Sdk v5.5.32

Affected platforms

WebAssembly, Android, iOS, Mac Catalyst, Skia (WPF)

IDE

Visual Studio 2022

IDE version

No response

Relevant plugins

No response

Anything else we need to know?

It might be related to x:Uid.

[jeromelaban]

Thanks for the report!

It looks like we're handling x:Uid incorrectly, most likely not filtering on the namespace:

uno/src/SourceGenerators/Uno.UI.SourceGenerators/XamlGenerator/XamlFileGenerator.cs

Line 3331 in 3a5478e

else if (member.Member.Name == "Uid")

It should be modified to read the attributes like this:

uno/src/SourceGenerators/Uno.UI.SourceGenerators/XamlGenerator/XamlFileGenerator.cs

Lines 3344 to 3345 in 3a5478e

	else if (member.Member.Name == "DefaultBindMode"
	&& member.Member.PreferredXamlNamespace == XamlConstants.XamlXmlNamespace)

[AndrewKeepCoding]

Thanks @jeromelaban! Is this a case I can just create a PR? or a case I should leave it to the team?

[jeromelaban]

@AndrewKeepCoding if you're up for it, go ahead! You can also add a test in this file:

uno/src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml/Given_xUid.cs

Line 17 in 6f15206

public class Given_xUid

[AndrewKeepCoding]

@jeromelaban Thanks!