Check if ContentPage is currently shown

Question

Is there a way to tell if a ContentPage is currently shown?

I need code inside an event handler in the ContentPage to check whether the page is currently shown and act accordingly.

Register event handlers OnAppearing and remove on Disappearing then you don't have to worry about it. If you are using event handlers for IPC you are going to have a bad time and might want to refactor things a bit. — snowCrabs, Feb 05 '18 at 21:18

hvaughan3 · Accepted Answer · 2018-02-05T19:36:50.260

5

In addition to GBreen12's answer, you could also do it this way...

bool isShowingMyPage = Application.Current.MainPage is MyPage || (Application.Current.MainPage is NavigationPage navPage && navPage.CurrentPage is MyPage); //If you are using a MasterDetailPage or something else, then you would have to handle this differently

//I think the below will work for checking if any modals are showing over your page but you should definitely test it in different scenarios to make sure. I am not sure if the modal is immediately removed from ModalStack when it gets popped or not

isShowingMyPage = Application.Current.MainPage?.Navigation?.ModalStack?.LastOrDefault() == null;

edited Feb 05 '18 at 19:36

answered Feb 05 '18 at 19:27

hvaughan3

10,955
5
56
76

What if this page has been "pushed" or "pushed modal" over the `MainPage`? – ispiro Feb 05 '18 at 19:30
@ispiro If a new page was "pushed" over `MyPage` then `Application.Current.MainPage` would hold the new page and not `MyPage`. If you also need to worry about whether a modal is showing over your `MyPage`, then check out my edit. – hvaughan3 Feb 05 '18 at 19:36
Checking for modals worked – jcubero Sep 26 '22 at 21:52

score 2 · Answer 2 · answered Feb 05 '18 at 19:12

2

You can override OnAppearing which is called anytime the page is about to be shown:

Page lifecycle events in xamarin.forms

answered Feb 05 '18 at 19:12

GBreen12

1,832
2
20
38

Thanks. I thought of that, and keeping a bool flag. But I wonder if there's any built in way. – ispiro Feb 05 '18 at 19:19
problem is on droid it fires before the page displays and on ios its after the page is displayed.. – Nick Kovalsky Feb 05 '18 at 22:25

score 1 · Answer 3 · answered Feb 06 '18 at 03:13

You can listen to the NavigationPage's Pushed and Popped events, like so:

((Xamarin.Forms.NavigationPage)MyProject.App.Current.MainPage).Pushed += (s, e) => 
{
    if (e.Page is ContentPage)
    {
        // Do what you gotta do
    }

    // or, for a specific page:
    if (e.Page is MyProject.Views.MyCustomPage)
    {
        // Do what you gotta do
    }
};

Of course, this will only be called when the page is pushed onto the navigation stack; If you need it to be called each time the page appears on the screen, then go with what GBreen12 or hvaughan3 said.

Check if ContentPage is currently shown

3 Answers3