Package System.Reactive.Windows.Threading 5.0.0 is not compatible with net462.

[Muhomorik]

Bug

Hello,

I have a project that targets 4.6.2 and is written in VB.Net and using WPF.
When trying to update RX to the latest version the package System.Reactive.Windows.Threading fails update with error below.

All other Rx packages like System.Reactive itself update without problem.
It is also strange that WinForms app that targets 4.6.2 seems be able to update to the same version.

Which library version?

System.Reactive.Windows.Threading 5.0.0

What are the platform(s), environment(s) and related component version(s)?

WPF, .Net 4.6.2

What is the use case or problem?

Nuget package doesn't target 4.6.2. And fails to install/update.

What is the expected outcome?

Package should install.

What is the actual outcome?

Severity	Code	Description	Project	File	Line	Suppression State
Error	NU1202	Package System.Reactive.Windows.Threading 5.0.0 is not compatible with net462 (.NETFramework,Version=v4.6.2). Package System.Reactive.Windows.Threading 5.0.0 supports:
  - net472 (.NETFramework,Version=v4.7.2)
  - uap10.0.16299 (UAP,Version=v10.0.16299)	WpfApp1

What is the stacktrace of the exception(s) if any?

None.

Do you have a code snippet or project that reproduces the problem?

Problem reproduces with a blank VisualBasic WPF app that targets 4.6.2.

[clairernovotny]

You should not need that package; those are old shims for compatibility for libraries built against very old versions of Rx. You should just need System.Reactive.

[Muhomorik]

Hello,

What is the equivalent code for ObserveOnDispatcher?

        Observable
            .Interval(TimeSpan.FromSeconds(5))
            .ObserveOnDispatcher()
            .Subscribe(
                x => { Console.WriteLine("Tick."); });

A lot of samples use that code, but now can't be used.
And classes from .Net 5 changes are not shown in ide.

[clairernovotny]

These are all in System.Reactive already.

Rx v5 requires .NET 4.7.2 or higher; .NET 4.6.2 is not supported.

The support lifecycle of .NET Framework is here
https://docs.microsoft.com/en-US/lifecycle/faq/dotnet-framework

If you target .NET 5, make sure to use the net5.0-windows10.0.19041 TFM as we require the latest SDK (older versions of Windows can be targeted).

[JiriZidek]

Rx v5 requires .NET 4.7.2 or higher; .NET 4.6.2 is not supported.

I'd suggest to correct the Readme page to reflect this information:

[Muhomorik]

I think the problem is that latest Visual Studio (16.9.1) designer doesn't recognize net5.0-windows10.0.19041 as a target (but will compile and run).
And net5.0-windows is equivalent to net.5.0-windows7.0

You can't select it in drop-down and when changed in code it will be shows as empty line in drop-down.