UserControl does not compile with WinAppSDK

[ArchieCoder]

Current behavior

When the WinAppSDK target is selected, my 2 UserControls don't compile:

Severity Code Description Project File Line Suppression State Details
Error WMC0001 Unknown type 'TitleWithAppControl' in XML namespace 'clr-namespace:ElementsTechnician.Presentation;assembly=Test, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null' Test C:\Users\sebas\Downloads\ElementsTechnician\ElementsTechnician\Presentation\MainPage.xaml 111

It compiles fine with the other targets.

Expected behavior

It should compile with all targets.

My user control is simply a StackPanel with a TextBlock

<StackPanel
    Background="Blue"
    Orientation="Horizontal"
    Padding="8">

    <TextBlock
        FontSize="30"
        Foreground="White"
        HorizontalAlignment="Center"
        Text="Blue"
        VerticalAlignment="Center" />

</StackPanel>

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

Open this sample app and compile Test.zip

Workaround

No response

Works on UWP/WinUI

Yes

Environment

No response

NuGet package version(s)

No response

Affected platforms

Windows (WinAppSDK)

IDE

Visual Studio 2022

IDE version

No response

Relevant plugins

No response

Anything else we need to know?

No response

[Youssef1313]

In MainPage.xaml, you have xmlns:presentation="clr-namespace:ElementsTechnician.Presentation"

This should be replaced by xmlns:presentation="using:ElementsTechnician.Presentation"

The fact that it compiles in Uno targets is a behavior that we will likely change a breaking change to keep parity with WinUI.

This is the same scenario from #15813

[ArchieCoder]

Good catch, I confirm it compiles. I'm puzzled how I ended up with this xmlns line. I never write this explicitly, I always use what VS/Resharper suggests. I guess one of them was wrong.

[Youssef1313]

Probably ReSharper isn't able to recognize the XAML as "WinUI" XAML if it doesn't respect DefaultXamlRuntime.

Or maybe this could have happened if you were typing code while restore hasn't completed, in which case, the DefaultXamlRuntime property isn't yet set and probably VS and/or Rider falls back to WPF flavored XAML.