Generic.xaml defined in the project head is not taken into account

[jeromelaban]

Current behavior

Create a project with implicit styles defined in a Generic.xaml defined in the shared project of the heads. Use controls that use these styles.

Expected behavior

The controls are styled properly

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

No response

Workaround

Create another resource dictionary, named Styles/Controls.xaml, then reference it from App.xaml:

<Application.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <XamlControlsResources xmlns="using:Microsoft.UI.Xaml.Controls" />
            <ResourceDictionary Source="Styles/Controls.xaml" />
        </ResourceDictionary.MergedDictionaries>

    </ResourceDictionary>
</Application.Resources>

Works on UWP/WinUI

Yes

Environment

No response

NuGet package version(s)

4.6.19

Affected platforms

No response

IDE

No response

IDE version

No response

Relevant plugins

No response

Anything else we need to know?

Related to #10276

[ToddGlodek]

@jeromelaban - the workaround seems just fine if you have the ' Source="Styles/Controls.xaml" ' in the .Shared project.

However, I'm not sure how this works if the ResourceDictionary containing the control layouts is defined in a Uno Platform Library. Will adding a second XamlControlsResources entry pointing to a namespace in MyProject work?

          <XamlControlsResources xmlns="using:Microsoft.UI.Xaml.Controls" />
          <XamlControlsResources xmlns="using:MyProject.Controls" />

Or, to I a have to add the in every project that consumes the non-shared cross platform library (but somehow referring to the referenced assembly).

[jeromelaban]

<XamlControlsResources/> is specific to WinUI, you cannot reuse the type across.

Cross platform libraries support Generic.xaml (see here), it's only the head project that does not.

[mcNets]

@jeromelaban I'm facing another error that I am not sure if it is related. Using an implicit style in a custom control defined in a controls library. The errors disappears if I add and use a Key.

This is the Generic.xaml file:

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
					xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
					xmlns:local="using:UnoKeyboard.Controls">

	<Style TargetType="local:Keyboard">
		<Setter Property="Template">
			<Setter.Value>
				<ControlTemplate TargetType="local:Keyboard">
						<Border x:Name="PanelRoot"
								Width="{TemplateBinding Width}"
								Height="{TemplateBinding Height}"
								Background="{TemplateBinding Background}"
								BorderBrush="{TemplateBinding BorderBrush}"
								BorderThickness="{TemplateBinding BorderThickness}" />
				</ControlTemplate>
			</Setter.Value>
		</Setter>
	</Style>

	<Style TargetType="local:Keyboard">
		<Setter Property="Background"
				Value="{ThemeResource SystemControlBackgroundBaseLowBrush}" />
		<Setter Property="BorderThickness"
				Value="1" />
		<Setter Property="BorderBrush"
				Value="{ThemeResource SystemControlForegroundBaseMediumBrush}" />
	</Style>

</ResourceDictionary>

When I build the project that uses this control I'm getting that error several times:

1>CSC : error UXAML0001: Dictionary Item Style has duplicate key typeof(global::UnoKeyboard.Controls.Keyboard) .
1>CSC : error UXAML0001: Processing failed for file C:\Code\KeyboardControl\UnoKeyboard\Themes\Generic.xaml (System.InvalidOperationException: Dictionary Item Style has duplicate key typeof(global::UnoKeyboard.Controls.Keyboard) .
1>Done building project "UnoKeyboard.csproj" -- FAILED.