Can we target net8 with uno 4.8

[takla21]

We attempted to migrate our project, which currently uses Uno 4.8.39 from net7 to net8. On Android and iOS depending on the .NET version, it fails with the following errors:

error UXAML0001: Sequence contains no elements
4>CSC : error UXAML0001: Processing failed for file App.xaml (System.InvalidOperationException: Sequence contains no elements
error CS0103: The name 'InitializeComponent' does not exist in the current context
error CS1061: 'Shell' does not contain a definition for 'InitializeComponent' and no accessible extension method 'InitializeComponent' accepting a first argument of type 'Shell' could be found (are you missing a using directive or an assembly reference?)
error CS1061: 'Shell' does not contain a definition for 'MyRootPanel' and no accessible extension method 'MyRootPanel' accepting a first argument of type 'Shell' could be found (are you missing a using directive or an assembly reference?)
error CS1061: 'Shell' does not contain a definition for 'AppExtendedSplashScreen' and no accessible extension method 'AppExtendedSplashScreen' accepting a first argument of type 'Shell' could be found (are you missing a using directive or an assembly reference?)
error CS1061: 'Shell' does not contain a definition for 'RootNavigationMultiFrame' and no accessible extension method 'RootNavigationMultiFrame' accepting a first argument of type 'Shell' could be found (are you missing a using directive or an assembly reference?)
error CS1061: 'Shell' does not contain a definition for 'FocusHelper' and no accessible extension method 'FocusHelper' accepting a first argument of type 'Shell' could be found (are you missing a using directive or an assembly reference?)
error CS1061: 'Page1' does not contain a definition for 'InitializeComponent' and no accessible extension method 'InitializeComponent' accepting a first argument of type 'Page1' could be found (are you missing a using directive or an assembly reference?)
[...] All pages used on our app are also referenced with the same `InitializeComponent` message.

We are uncertain whether this issue is due to a missing configuration on our side or if upgrading to Uno 5 before migrating to net8 is needed.

Code referenced in the error message.

public sealed partial class Shell : UserControl
{
	public Shell()
	{
		this.InitializeComponent();

		Instance = this;
	}

	public Panel RootPanel => this.MyRootPanel;

	public static Shell Instance { get; private set; }

	public IExtendedSplashScreen ExtendedSplashScreen => this.AppExtendedSplashScreen;

	public MultiFrame NavigationMultiFrame => this.RootNavigationMultiFrame;

	public Control FocusableControl => this.FocusHelper;

#if __WINDOWS__
	public Control PopupFrame => this.MyPopupFrame;
#endif
}

using Microsoft.UI.Xaml.Controls;

public sealed partial class UpdatePromptPage : Page
{
	public UpdatePromptPage()
	{
		this.InitializeComponent();
	}
}

[kazo0]

@takla21 what does the App.xaml look like? That seems to be where the problem is

[jeromelaban]

@takla21 Uno 4.8 does not support .NET 8 indeed, there's a change in the way android resources are handled that breaks. It's fixed in Uno 4.10.x.

[takla21]

App.xaml

<Application x:Class="AppName.App"
			 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
			 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
			 RequestedTheme="Light">

	<Application.Resources>
		<ResourceDictionary>
			<ResourceDictionary.MergedDictionaries>
				<XamlControlsResources xmlns="using:Microsoft.UI.Xaml.Controls" />
				<!-- Load Toolkit resources -->
				<ToolkitResources xmlns="using:Uno.Toolkit.UI" />
				<ResourceDictionary Source="Styles/_Styles.xaml" />
			</ResourceDictionary.MergedDictionaries>
		</ResourceDictionary>
	</Application.Resources>

</Application>

_Styles.xaml

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    
    <ResourceDictionary.MergedDictionaries>
		<ResourceDictionary Source="Application/_Application.xaml" />
		<ResourceDictionary Source="Controls/_Controls.xaml"/>
	</ResourceDictionary.MergedDictionaries>
</ResourceDictionary>

_Application.xaml

<ResourceDictionary.MergedDictionaries>
		<ResourceDictionary Source="Colors.xaml" />
		<ResourceDictionary Source="Converters.xaml" />
		<ResourceDictionary Source="Fonts.xaml" />
		<ResourceDictionary Source="LayoutConstants.xaml" />
	</ResourceDictionary.MergedDictionaries>

_Controls.xaml

<!-- Please keep this list ordered alphabetically -->
	<ResourceDictionary.MergedDictionaries>
		<ResourceDictionary Source="AppBarButton.xaml" /> 
		<ResourceDictionary Source="Button.xaml" />
		<ResourceDictionary Source="CheckBox.xaml" />
		<ResourceDictionary Source="ComboBox.xaml" />
		<ResourceDictionary Source="ComboBoxItem.xaml" />
		<ResourceDictionary Source="CommandBar.xaml" />
		<ResourceDictionary Source="ContentControl.xaml" />
		<ResourceDictionary Source="ContentPresenter.xaml" />
		<ResourceDictionary Source="Frame.xaml" />
		<ResourceDictionary Source="GridViewHeaderItem.xaml" />
		<ResourceDictionary Source="GridViewItem.xaml" />
		<ResourceDictionary Source="ItemsControl.xaml" />
		<ResourceDictionary Source="ListView.xaml" />
		<ResourceDictionary Source="ListViewHeaderItem.xaml" />
		<ResourceDictionary Source="ListViewItem.xaml" />
		<ResourceDictionary Source="PasswordBox.xaml" />
		<ResourceDictionary Source="RadioButton.xaml" />
		<ResourceDictionary Source="SplitView.xaml" />
		<ResourceDictionary Source="TextBlock.xaml" />
		<ResourceDictionary Source="TextBox.xaml" />
		<ResourceDictionary Source="ToggleButton.xaml" />
		<ResourceDictionary Source="ToggleSwitch.xaml" />
                <!-- And many other custom control styles -->
	</ResourceDictionary.MergedDictionaries>

[takla21]

@jeromelaban is right. I don't encounter that issue with uno 4.10