Xamarin Forms - Prism detect GoBack

Question

Using Xamarin.Forms v4.5 and Prism v7.2

I have an APP with 3 pages (PageA, PageB and PageC).

From PageA, I can navigate to PageB and from PageB to PageC. From PageC, I can tap on the back button and go back to PageB.

My question is, when I navigate to PageB (either from PageA or PageC), is there a method that Prism provides to identify whether I end up to PageB by pressing the back button?

I have added an anwser, i have updated alot since i post it, so you may have not noticed — Ricardo Dias Morais, Mar 09 '20 at 16:52

score 6 · Accepted Answer · answered Mar 09 '20 at 17:39

At this time Xamarin.Forms does not provide a way to hook into the underlying Navigation Service and intercept the full Navigation process in certain flows such as when someone clicks on a hardware back button. As a result we are limited in what we can do and are therefore not able to support IConfirmNavigation to allow you to prevent navigating away.

That having been said we are able to observe that a Page was popped and we are still able to invoke OnNavigatedFrom/OnNavigatedTo. You can easily determine what has occurred by getting the NavigationMode. To do this your code might look like this:

public void OnNavigatedTo(INavigationParameters parameters)
{
    var mode = parameters.GetNavigationMode();
    switch(mode)
    {
        case NavigationMode.New:
            break;
        case NavigationMode.Back:
            break;
        case NavigationMode.Forward:
            break;
    }
}

Ok, i completly agree with you. didn't know navigation parameters had a Navigation Mode, i will delete my anwser since this should be the correct way, time to update my projects, because this is very helpful — Ricardo Dias Morais, Mar 09 '20 at 17:42

Xamarin Forms - Prism detect GoBack

1 Answers1