Hold Values in Objects for back navigation UWP

Question

I am working on a Template 10 MVVM based UWP application.

Current Scenario

I am getting the data from an api and creating a local IEnumerable property named HugeDataConsumer on the viewModel.

What's happening:

After navigation, to another view, when I press back and comeback to my mainView, the HugeDataConsumer IEnumerable becomes null because the ViewModel is created again.

what I want to achieve:

I want my ViewModel to hold the value of the HugeDataConsumer IEnumerable so that the navigation back event feels like a state resumed. I have tried setting the NavigationCacheMode = Windows.UI.Xaml.Navigation.NavigationCacheMode.Required; on my codeBehind, but I don't think it applies to my viewModel as well. Is there a way to achieve this?

Answer 1

You can manually serialize your data using DataContractSerializer and deserialize it back when you navigate to the main view model. Prism is using a service called SessionStateService to do such things.

NavigationCacheMode does not apply to the context. It only cashes the view itself, not the model.

You can always cache your data using your own static classes but I think everybody will agree with me if I say developers hate static classes.

Also, if you are developing a UWP app do not forget the suspension scenarios. Whenever your app gets suspended your OnNavigatedTo will fired with a NavigationMode Refresh parameter when the user gets back to the app.