ObservableProperty code not being generated

[CADTraveller]

I'm trying to utilize this toolkit in a WPF 4.7.2 application. I have brought in CommunityToolkit.Mvvm V8.0.0 (preview 4). The I had my main VM inherit from ObservableObject:

using CommunityToolkit.Mvvm.ComponentModel;

namespace hsbWPF.Revit.UI.ViewModels
{
    public partial class ParametersMainViewModel : ObservableObject
    { ...

However, the 'partial' declaration is dim since there is no other partial class. When I mark a field with the [ObservableProperty] attribute there is no matching Public property generated. Nothing shows up in the Analyzers section of References:

Is there a limitation around C# or Framework versions?

What else can I check?

[Sergio0694]

Just to double check, is the code just not showing up there or is it just not being generated at all?
As in, if you try to use the generated property and build, does it fail to build?
Do you see any errors in the output window?

[CADTraveller]

Ah, no. I think I found the heart of the issue. My projects are C# 7.3.

Error MVVMTK0008 The source generator features from the MVVM Toolkit require consuming projects to set the C# language version to at least C# 8.0 Revit.PropertyData X:\HsbDefault\BeamApp\Hsb_NetApi\hsbWPF.Properties.UI\Revit.PropertyData\CSC 1

To work with the rest of our internal code I'm limited to .NET Standard 2.0. So, the Toolkit is not applicable for me currently.

Thanks for your assistance @Sergio0694

[Sergio0694]

I'm confused, weren't you getting that diagnostic error before? It should've showed up, no?
Also, FYI you can manually set the language version to C# 8.0 if you want: add <LangVersion>8.0</LangVersion> to your .csproj.

[CADTraveller]

I had not seen that error message in my original WPF project.

I know I can manually set the C# version, but .NET Standard 2.0 doesn't support C# 8.0 does it?

[Sergio0694]

"I had not seen that error message in my original WPF project."

Mmh that's not good, we should still be able to show that diagnostic. I wonder if that's just a tooling issue 🤔
I'll try to see if I can repro. Just to confirm: is your WPF project using an SDK-style .csproj, or old-style? What TFM are you using?

"but .NET Standard 2.0 doesn't support C# 8.0 does it?"

Eh, good question. Officially, no. But, you can bump the version manually and most things will still work. Some will require some additional work. Some will just not work, but you can just not use those. I've written an overview here, if it helps 🙂

[CADTraveller]

My WPF project is Framework 4.7.2 with the old style csproj file. Working with a bunch of legacy code and doing libraries for AutoCAD and Revit, we're kind of constrained...

Nice article @Sergio0694 , I'd found a similar one from James M. but yours is a bit newer. And indeed, adding the element worked! Code is generated as expected. I still need to do some integration testing but this issue is closed.

Thanks again for your prompt response and useful feedback ;-]

[CADTraveller]

Moving the ViewModels to a .NET Standard library that uses C# 8.0 enabled the Toolkit Code Generation.