[BUG] WPF: WhenActivated not fired when in ViewModelViewHost

[zperak]

Describe the bug
In version 9.14.1, in commit [a1cb284] MSBuild.Sdk.Extras was updated to v2.0.24 (from 1.6.68). Also ExtrasEnableWpfProjectSetup tag is changed to UseWpf.
After these two changes in WPF project, WhenActivated event does not fire when loaded into ViewModelViewHost.
When MSBuild.Sdk.Extras is rolled back to version 1.6.68 and UseWpf changed back to ExtrasEnableWpfProjectSetup in ReactiveUI.Wpf/ReactiveUI.Wpf.csproj then everything works again, i.e. this.WhenActivated in view loaded into ViewModelViewHost fires again.

Steps To Reproduce
In attached simple WPF project (DebugWhenActivated.zip):

1. In App.xaml.css add: Locator.CurrentMutable.RegisterViewsForViewModels(Assembly.GetCallingAssembly());
2. In MainWindow.xaml add ViewModelViewHost
3. In MainWindow.xaml.cs bind ViewModelViewHost.ViewModel with MainDocViewModel which is ViewModel for MainDocView.xaml (Reactive)UserControl

Expected behavior

1. ViewModelViewHost loads MainDocView.xaml
2. In MainDocView.xaml.cs constructor this.WhenActivated is fired

Actual behavior

1. The same
2. this.WhenActivated is not fired

Environment

• OS: Windows 10
• Version 1809
• Device: PC laptop
• IDE: Visual Studio 2019 Enterprise

Additional context
To investigate issue, I have added ReactiveUI and ReactiveUI.Wpf as projects dependencies to my test app (DebugWhenActivated). I had to remove most targets from ReactiveUI.csproj to be able to compile project.
You can get the same result if you add dependency via NuGet: Version 9.13.1 works ok and in 9.14.1 this.WhenActivated does not work if loaded into ViewModelViewHost.

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[glennawatson]

Will take a look at this one today. Thanks for the detailed report

[glennawatson]

Should be fixed in 9.14.3

[zperak]

Hi @glennawatson,

I have just tried new version and the problem still exists. WhenActivated does not fire when in ViewModelViewHost. When MSBuild.Sdk.Extras is rolled back to version 1.6.68 everything works fine.
It must be something in version 2 of MSBuild.Sdk.Extras. I tried all available 2.x versions and problem exists with all of them.

[glennawatson]

When I ran it with your sample with latest rxui, it was firing and triggering the Console.WriteLine()

[glennawatson]

I'm going to reopen it. With the NuGet package getting the same issue. Will work on reverting to 1.6.68 now. Thanks

[glennawatson]

Also might be worthwhile opening an issue about this in https://github.com/onovotny/MSBuildSdkExtras/tree/master/Source/MSBuild.Sdk.Extras

GitHub

onovotny/MSBuildSdkExtras

Extra properties for MSBuild SDK projects. Contribute to onovotny/MSBuildSdkExtras development by creating an account on GitHub.

[zperak]

@glennawatson thanks a lot!