Uno Specific Preprocessor Directives don't work

[michael-hawker]

Related to #174 maybe as we should update Uno version first.

Effects Experiment: #101

According to Uno docs here around platform specific C# code. We should be able to use the following values:

Platform	Symbol
UWP	NETFX_CORE
Android	__ANDROID__
iOS	__IOS__
WebAssembly	HAS_UNO_WASM
macOS	__MACOS__
Skia	HAS_UNO_SKIA

I know we've been able to use a general HAS_UNO one (which is not listed in the doc?) and we define our own WINAPPSDK one. I also know the NETFX_CORE one works.

However trying to use __WASM__ or HAS_UNO_WASM is not working.

This makes the logic needed to guard against the Uno NotImplemented error in the CI and having the code actually work in WASM for SizerBase not work properly.

We need to understand what's going on here so we can properly guard code against specific platforms (if needed).

See Uno file here for reference as well.

[Arlodotexe]

I've never used HAS_UNO_WASM before, but __WASM__ has always worked as expected for me.

[michael-hawker]

@Arlodotexe I can confirm that the place I'm using it in SizerBase is not working as the mouse cursor is being disabled unless I comment out the #if so something is missing in the Labs configuration:

Labs-Windows/labs/SizerBase/src/Toolkit/FrameworkElementExtensions.Mouse.cs

Lines 80 to 83 in 2cd42b2

	#if NETFX_CORE || __WASM__ || __MACOS__ || __SKIA__
	CoreCursorType cursor = GetCursor((FrameworkElement)sender);
	Window.Current.CoreWindow.PointerCursor = _cursors[cursor];
	#endif

This is only working on UWP currently as written due to the NETFX_CORE. I added this after we got CI exceptions because the other platforms through the Uno not implemented warning/error.

[Arlodotexe]

Perhaps something just isn't implemented fully on Uno's side for WASM?

This might help => https://platform.uno/docs/articles/features/cursors.html

[michael-hawker]

Perhaps something just isn't implemented fully on Uno's side for WASM?

This might help => https://platform.uno/docs/articles/features/cursors.html

It is working, I think their document is out-of-date. I have validated already that the __WASM__ pre-processor directive is not-working within our source. It is the root of the issue. The Cursor code is fine when unguarded, but triggers issues in the build on the other platforms, so it needs to be guarded.

[Arlodotexe]

@michael-hawker We can always add it back using our Labs.Wasm.props file.

[michael-hawker]

@michael-hawker We can always add it back using our Labs.Wasm.props file.

The Labs.Wasm.props is for WASM heads, but this is in the multi-targeted library, so it's not that simple. (That was the first thing I thought of initially, but that only works for cases where we need to do something specific in our sample app vs. a component.)

[Arlodotexe]

I've also confirmed that these aren't always working as intended.

I've got a solution that will fix these for us and make them work as expected, even in multitargeted libraries.