Code inside of OnNavigatedTo implementation breaks navigation

[jruiz91]

Description
I have a little Prism WPF project just to test Prism navigation. It contains a view with list of objects (in this case apples) and another view that shows their detail.

When going back from the apple's detail to the list, I need to perform some actions such as refreshing the list of apples in case any apple has been added/modified. But, when I add any code other than a console log to the OnNavigatedTo method of the list's viewmodel, the app won't go back to the list on the first attempt event though the OnNavigatedTo method is being called.

Steps to reproduce
The navigation works fine if:

1. Leave AppleListModelView's OnNavigatedTo method implementation empty.
2. Build the project. Run it.
3. Click on any apple of the list so that its detail is shown.
4. Click on the go back button (the one that has a left arrow).
5. The list is shown the first time this button is clicked.

The navigation won't work if:

1. Add any code other than a System.Console.WriteLine to the OnNavigatedTo method of AppleListModelView.
2. Follow the steps 2, 3 and 4 of the previous list.
3. The list is not shown.
4. Click again on the go back button.
5. The list is shown.

Expected behaviour
OnNavigatedTo method is called and upon finishing, the list should be shown.

Actual behaviour
OnNavigatedTo method is called but the list is not shown the first time.

Basic information

• Prism Unity version: 8.0.0.1909
• Last known good version: x
• .NET Framework version: 4.7.2
• IDE: VS 16.9.2

Here is the commit that breaks the navigation and here the project's repository.

[jruiz91]

The problem had nothing to do with Prism.

I was unaware of the SelectionChanged event of the DataGrid that contains the list of apples being fired when the OnNavigatedTo method performs the instruction this.SelectedApple = null.

I've uploaded the fix to that problem here.

My apologies.