[Preview4] Window.Current is null

[sonnemaf]

Describe the bug
The Window.Current is 'null in a Desktop project. I use it to retrieve whether the Ctrl and Shift keys are Down. Using CoreWindow.GetKeyState(). I hope there is an workaround for retrieving the KeyState.

Steps to reproduce the bug

Steps to reproduce the behavior:

1. Build a Preview 4 WinUI app.
2. Inspect the Microsoft.UI.Xaml.Window.Current property.

Expected behavior
It should not be null

Screenshots

Version Info

NuGet package version:
[Microsoft.WinUI 3.0.0-preview4.210210.4]

Windows app type:

UWP	Win32
No	Yes

Windows 10 version	Saw the problem?
Insider Build (xxxxx)
October 2020 Update (19042)	Yes
May 2020 Update (19041)
November 2019 Update (18363)
May 2019 Update (18362)
October 2018 Update (17763)
April 2018 Update (17134)
Fall Creators Update (16299)
Creators Update (15063)

Device form factor	Saw the problem?
Desktop	Yes
Xbox
Surface Hub
IoT

Additional context

[sonnemaf]

@azchohfi found a workaround for my GetKeyState() problem. I should use KeyboardInput.GetKeyStateForCurrentThread() instead. Thanks you.

https://twitter.com/AlexandreChohfi/status/1360274722517254145

[StephenLPeters]

@anawishnoff FYI @MikeHillberg

[MikeHillberg]

We're working on documentation to list the APIs that behave differently on Desktop compared to UWP (several new to Preview4), we'll make sure this one is there.

[krschau]

We're working on documentation to list the APIs that behave differently on Desktop compared to UWP (several new to Preview4), we'll make sure this one is there.

Here's the doc: https://docs.microsoft.com/en-us/windows/apps/desktop/modernize/desktop-to-uwp-supported-api