Route registration in MAUI

[david-maw]

While the idea of automatically registering routes seems like a good one in principle, the Shell object itself registers the pages used in ShellContent objects, so in the typical AppShell.xaml you might see something like:

<Shell
    ....
    <ShellContent Title="Main" ContentTemplate="{DataTemplate local:MainPage}" Route="Main"/>
    <ShellContent Title="List" ContentTemplate="{DataTemplate local:ListPage}" Route="List"/>
</Shell>

Then in AppShell.xaml.cs there would be Routing.RegisterRoute("details", typeof(DetailsPage)).

You would probably not want to re-register the pages already registered by ShellContent items unless you want to be able to navigate to new instances of them, which is what registering them seems to enable. In the example above I'd speculate most people want to use Shell.Current.GoToAsync("//Main") rarely Shell.Current.GoToAsync("Main").

So, bottom line, you probably need to distinguish the two types of pages which isn't terribly hard to do (by name suffix, for example), but it's probably worth some thought.

[ewerspej]

The route generator doesn't register any routes automatically.

You still have to do this yourself, e.g. when using MAUI it would look like this:

foreach (var route in Routes.RouteTypeMap)
{
    Routing.RegisterRoute(route.Key, route.Value);
}

Hence, you could just modify that loop to skip routes that are already registered or that you know will be registered by Shell itself.

You can also register routes differently outside of the loop:

Routing.RegisterRoute("//Main", Routes.RouteTypeMap[Routes.MainPage]);

[david-maw]

Sorry, I wasn't trying to suggest RouteGenerator currently registered routes, it's just that doing so was in "Future Ideas" and the interaction between routes in ShellContent items and those in RegisterRoute is less than straightforward to say the least. You can have the same route in both with different meanings, or even pointing to different page classes if you're especially masochistic. This looks like it makes automated registration in non-trivial cases challenging, which is perhaps not obvious to the casual observer.

All that said, if you don't abuse the routing mechanism RouteGenerator works well, so thanks. I've even gone as far as to use the generated routes in XAML to improve reference checking (the VS "code search" feature will find them in XAML). For example (the app in this case is called DivisiBill):

<Shell xmlns="http://schemas.microsoft.com/dotnet/2021/maui" 
...
       xmlns:view="clr-namespace:DivisiBill.Views"
       xmlns:local="clr-namespace:DivisiBill"
...
    <ShellContent Title="Items" ContentTemplate="{DataTemplate view:LineItemsPage}" Route="{x:Static local:Routes.LineItemsPage}"/>
    <ShellContent Title="Totals" ContentTemplate="{DataTemplate view:TotalsPage}" Route="{x:Static local:Routes.TotalsPage}"/>
</Shell>