Support PrimaryLanguageOverride from unpackaged apps

[shelllet]

when calling the following code from an unpackaged app, it throws an error. This is needed to be able to use x:Uid localization in XAML and control the language it picks.

App::App()
{
    ...
    Windows::Globalization::ApplicationLanguages::PrimaryLanguageOverride(...)
    ...
}

[btueffers]

Hi @shelllet, this API isn't intended to work from an unpackaged context.

[andrewleader]

Additionally, we've started a list of APIs like this that don't work from unpackaged apps that we need to either (1) document better with warnings so you know before you try using it, or (2) add new WinAppSDK APIs that work for unpackaged apps: #1702

[shelllet]

So what Api should I call to set the defualt language?

[andrewleader]

@axelandrejs how should unpackaged apps set their default language for resolving resources and XAML localization?

[huichen123]

MRTCore determines the default language using Windows::Globalization::ApplicationLanguages::Languages (https://github.com/microsoft/WindowsAppSDK/blob/main/dev/MRTCore/mrt/Microsoft.Windows.ApplicationModel.Resources/src/ResourceContext.cpp#L106-L113)

[andrewleader]

@huichen123 but how should unpackaged apps change the default language for their app? As shelllet pointed out, in a packaged app, developers can call ApplicationLanguages::PrimaryLanguageOverride('en-us') to override the default language, but that API doesn't work for unpackaged apps. How should unpackaged apps override the default language when using MRT Core?

Many apps (including my own) allow the user to pick their own language independent from the OS language.

[huichen123]

Before PrimaryLanguageOverride is fixed, you may have to pass in a ResourceContext, and set its Language qualifier value to the desired value.

[seven-mile]

Before PrimaryLanguageOverride is fixed, you may have to pass in a ResourceContext, and set its Language qualifier value to the desired value.

Will these unpackaged API be fixed before GA version? This breaks x:Uid localization and seems to have no workaround.

[huichen123]

sorry, it will not be fixed for GA.