UWP -> WinUI3: ViewModelLocator.Current

[myokeeh]

In the WTS generated UWP app I'm converting to WinUI3/WindowsAppSDK, I call my method SetBusy() using ViewModelLocator.Current.ShellViewModel.SetBusy(false);

What is the equivalent to ViewModelLocator.Current to allow me to call SetBusy() in the same manner?

[myokeeh]

It appears to be App.GetService<ShellPage>().ViewModel

See #4585 (reply in thread)

[myokeeh]

I see. I think I'm back to my original question. I can't grasp how to access the proper instance of the displayed page's ViewModel from App.xaml.cs.

[mikebattista]

App.xaml.cs could raise an event that the ViewModel registers for. The ViewModel could assign itself to a static property on the App class so that the App can reference the instance that way. You could try changing AddTransient to AddSingleton for the Page and ViewModel in App.xaml.cs and see if that helps with the App.GetService approach as well. These are just a few ideas without knowing much about your app's construction and layering.

[myokeeh]

I changed services.AddTransient<ShellViewModel>(); to services.AddSingleton<ShellViewModel>(); as you suggested.

Now App.GetService<ShellViewModel>().SetBusy() seems to address my initial question, though I don't know if this is the best thing to do. Time to learn more about what I just changed.

For now, I'm happy it's giving me the result I want.

Thanks!

[mikebattista]

Glad you got it working.

Service lifetime is explained at https://docs.microsoft.com/dotnet/core/extensions/dependency-injection#service-lifetimes.

[myokeeh]

@mikebattista I have forgotten about this thread and in my 2024 attempt to get back to using this, I ran into the same issue creating a new project from scratch.

Why is Transient the default in this case? It just seems like a wild-goose chase for someone trying to get started.