Beginner's confusion about navigation

[GKdev1980]

Hi. I've started watching some beginner tutorial videos on Maui and I must say some simple tasks already got me a bit confused, because I see different ways to do them in different videos.

For example navigation between pages. The very first video I saw used routing. You define a Route string inside the ShellContent tag in the AppShell.xaml and then i the code-behind you register it with:
Routing.RegisterRoute("NewPage", typeOf('PageName')).
So then, when I need to navigate to that page I can simply use:
await Shell.Current.GoToAsync("NewPage");
Seemed simple enough, didn't pass any arguments though (I don't know if that would be possible with this method).

I'm watching a different video now and he's using a different approach. We create a different ContentPage, let's say "NewPage" and then we can navigate to that page from another page simply by using:
Navigation.PushAsync(new NewPage());
In fact, we could pass some arguments this way by changing the constructor of the NewPage and passing the appropriate argument inside the PushAsync method.

What's the deal here? Are there 2 different ways to do the same thing? Are there any other differences or cases I would prefer one over the other? Or am I that confused that they are used in different cases?

[acaliaro]

I believe the difference is in using or not using "shell".
The "GoToAsync" approach is related to using the shell, which is the new navigation mode, while "push" and "pop" are related to the navigation implemented in Xamarin. The choice of using "shell" or "navigation" is free.

[GKdev1980]

Ok. So, are there any advantages/disadvantages on choosing one approach over the other? Are there any things I can do with shell that I cannot do with Navigation push/pop or vice versa?

[acaliaro]

https://www.youtube.com/watch?v=dM4PhZAUhzU&t=888s

[GKdev1980]

I see. So in a nutShell (sorry, I couldn't help myself :P) Shell is a newer and more "structured" way to organize my app, which is very helpful in complicated applications but may add a bit of complexity in simpler apps consisting maybe of just a few ContentPages.

I'll probably try to get my hand around Shell from the beginning.

[Ghostbird]

I have the opposite experience. AppShell is very nice for simple apps, and is simple to write. The navigation stack mechanism requires you as the developer to manually keep track of more things.

Using Shell also does not preclude using the navigation stack. I have ported a Xamarin app to MAUI and now use AppShell for most routing because it works in a less complicated way in my opinion. However there's one page where pressing a button will still push a new (modal) page on the stack, and pop it off after the action is completed, because it makes much more sense in that specific context.

Most importantly, the AppShell approach is not suitable to apps where a page of a certain type can navigate to a different instance of a page of that type. AppShell routing, AFAIK, only manages a single instance of each type of page. That would mean that when you navigate to the second instance, you would actually go to the same instance that's already loaded. Then you'll have to reset it, and load different data in that instance. Then when you navigate back, you have to restore the original state.

[leomelin]

I was also very confused about when to use PushAsync and when to use GoToAsync and it all seems to boil down to whether you want the back button to work correctly.

I just want to share my findings here:

• If you have a shell app and you need to open another page that is not set in AppShell ShellContent and you want to be able to navigate "back" from that, you need to append the new page into shell's navigation stack. You can do it by calling: Shell.Current.Navigation.PushAsync(new SpecialPage());. When using this approach, you can have a basic navigation with like bottom tabs with no top navbar visibe and then if you need to navigate to the "SpecialPage", you can set there in the XAML Shell.NavBarIsVisible="True" and when the SpecialPage is displayed, you have top NavBar with backbutton visible.

• I first tried using global Navigation.PushAsync but it seems to create a completely separate navigation stack and the backbutton doesn't work correctly and I also got the thing crashing all the time when trying to do navigation. But now that I've fiddled with this, it seems pretty obvious that the shell app has it's own Navigationstack instance that you have to use.

• If you have a route that can be addressed via route name, like //Mypage/dogs then you should use
  Shell.Current.GoToAsync("//Mypage/dogs")

Hope this helps some other beginner like me who has banged head against the wall with the navigation.