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maui-shell-navigation【文档与办公】Guide for implementing Shell-based navigation in .NET MAUI apps. Covers AppShell setup, visual hierarchy (FlyoutItem, TabBar, Tab, ShellContent), URI-based navigation with GoToAsync, route registration, query parameters, back navigation, flyout and tab configuration, navigation events, and navigation guards. Use when: setting up Shell navigation, add…
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Implement page navigation in .NET MAUI apps using Shell. Shell provides URI-based navigation, a flyout menu, tab bars, and a four-level visual hierarchy — all configured declaratively in XAML.
GoToAsyncmaui-data-bindingmaui-dependency-injectionNavigationPage without Shell (different navigation API)AppShell.xaml as the root shellContentPage) to navigate betweenThese are the Shell-specific decisions that are easy to get wrong. Apply them whenever they are relevant to what the user asked.
| Situation | Do this | Not this |
|---|---|---|
Declaring pages in AppShell.xaml | With xmlns:views="clr-namespace:MyApp.Views" declared: <ShellContent ContentTemplate="{DataTemplate views:MyPage}" /> — the page is created on first navigation | <ShellContent><views:MyPage /></ShellContent>, which constructs every page at startup |
| Navigating to a page not in the visual hierarchy | Routing.RegisterRoute("details", typeof(DetailsPage)) first | Calling GoToAsync("details") unregistered — it throws at runtime |
| Receiving navigation parameters | Implement IQueryAttributable on the ViewModel | Implementing it on the Page, which splits state from the BindingContext |
| Passing a whole object | ShellNavigationQueryParameters | Serialising the object into the query string |
Any GoToAsync call | await it | Fire-and-forget — exceptions are swallowed and navigation races |
| Confirming before back navigation | ShellNavigatingEventArgs.GetDeferral() … deferral.Complete() | Blocking synchronously on the dialog task |
| Detecting back navigation | Check e.Source == ShellNavigationSource.Pop | Assuming every navigation is a back action |
Do not propose NavigationPage / PushAsync solutions for a Shell app, and do
not restructure a working AppShell hierarchy unless the user asked.
Answer narrowly, but completely. Staying on topic does not mean being terse. When
you show a navigation change, include the pieces needed to run it: the AppShell.xaml
markup and the Routing.RegisterRoute call, or the GoToAsync call and the
receiving IQueryAttributable / [QueryProperty] code. Where two approaches are both
valid (query string vs ShellNavigationQueryParameters), show both and say when each
fits — a single snippet the user still has to complete is a worse answer.
Shell uses a four-level hierarchy. Each level wraps the one below it:
Shell
├── FlyoutItem / TabBar (top-level grouping)
│ ├── Tab (bottom-tab grouping)
│ │ ├── ShellContent (page slot → ContentPage)
│ │ └── ShellContent (multiple = top tabs)
│ └── Tab
└── FlyoutItem / TabBar
Tab childrenShellContent; multiple children produce top tabsContentPageYou can omit intermediate wrappers. Shell auto-wraps:
| You write | Shell creates |
|---|---|
ShellContent only | FlyoutItem > Tab > ShellContent |
Tab only | FlyoutItem > Tab |
ShellContent in TabBar | TabBar > Tab > ShellContent |
AppShell.xaml inheriting from ShellFlyoutItem or TabBar elements for top-level navigationTab elements for bottom tabs; nest multiple ShellContent for top tabsContentTemplate with DataTemplate so pages load on demandShellContent an explicit Route (see below)AppShell constructorSet
Route=on everyShellContent. If you omit it, MAUI auto-generates a name from a shared counter —Routing.csproducesD_FAULT_{TypeName}{n}. A real shell with three unnamedShellContentelements yields routes likeD_FAULT_ShellContent2andD_FAULT_ShellContent5: the numbers are not sequential, they depend on how many Shell elements were constructed first, and they shift when you reorder or add pages. You cannot write a stable absolute route (//dashboard) or deep link against that. An explicitRoute="dashboard"is stable forever.
<Shell xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:views="clr-namespace:MyApp.Views"
x:Class="MyApp.AppShell"
FlyoutBehavior="Flyout">
<FlyoutItem Title="Animals" Icon="animals.png">
<Tab Title="Cats">
<ShellContent Title="Domestic" Route="domesticcats"
ContentTemplate="{DataTemplate views:DomesticCatsPage}" />
<ShellContent Title="Wild" Route="wildcats"
ContentTemplate="{DataTemplate views:WildCatsPage}" />
</Tab>
<Tab Title="Dogs" Icon="dogs.png">
<ShellContent Route="dogs" ContentTemplate="{DataTemplate views:DogsPage}" />
</Tab>
</FlyoutItem>
<TabBar>
<ShellContent Title="Home" Icon="home.png" Route="home"
ContentTemplate="{DataTemplate views:HomePage}" />
<ShellContent Title="Settings" Icon="settings.png" Route="settings"
ContentTemplate="{DataTemplate views:SettingsPage}" />
</TabBar>
</Shell>
// AppShell.xaml.cs
public partial class AppShell : Shell
{
public AppShell()
{
InitializeComponent();
Routing.RegisterRoute("animaldetails", typeof(AnimalDetailsPage));
Routing.RegisterRoute("editanimal", typeof(EditAnimalPage));
}
}
All programmatic navigation uses Shell.Current.GoToAsync. Always await the call.
| Prefix | Meaning |
|---|---|
// | Absolute route from Shell root |
| (none) | Relative; pushes onto the current nav stack |
.. | Go back one level |
../ | Go back then navigate forward |
// 1. Absolute — switch to a specific hierarchy location
await Shell.Current.GoToAsync("//animals/cats/domestic");
// 2. Relative — push a registered detail page
await Shell.Current.GoToAsync("animaldetails");
// 3. With query string parameters
await Shell.Current.GoToAsync(quot;animaldetails?id={animal.Id}");
// 4. Go back one page
await Shell.Current.GoToAsync("..");
// 5. Go back two pages
await Shell.Current.GoToAsync("../..");
// 6. Go back one page, then push a different page
await Shell.Current.GoToAsync("../editanimal");
Implement on ViewModels to receive all parameters in one call:
public class AnimalDetailsViewModel : ObservableObject, IQueryAttributable
{
public void ApplyQueryAttributes(IDictionary<string, object> query)
{
if (query.TryGetValue("id", out var id))
AnimalId = id.ToString();
}
}
Apply on the ViewModel class (or the page, if it genuinely owns the state).
Prefer IQueryAttributable on the ViewModel — it keeps navigation state with the
BindingContext and handles multiple parameters in one call:
[QueryProperty(nameof(AnimalId), "id")]
public partial class AnimalDetailsViewModel : ObservableObject
{
[ObservableProperty]
private string _animalId = string.Empty;
}
Shell applies query attributes after the page constructor sets BindingContext,
so the property must raise change notification — a plain auto-property leaves the
binding stuck on its initial value.
Pass objects without serializing to strings:
var parameters = new ShellNavigationQueryParameters
{
{ "animal", selectedAnimal }
};
await Shell.Current.GoToAsync("animaldetails", parameters);
Receive via IQueryAttributable:
public void ApplyQueryAttributes(IDictionary<string, object> query)
{
Animal = query["animal"] as Animal;
}
Use GetDeferral() in OnNavigating for async checks (e.g., "save unsaved changes?"):
// In AppShell.xaml.cs
protected override async void OnNavigating(ShellNavigatingEventArgs args)
{
base.OnNavigating(args);
if (hasUnsavedChanges && args.Source == ShellNavigationSource.Pop)
{
var deferral = args.GetDeferral();
bool discard = await ShowConfirmationDialog();
if (!discard)
args.Cancel();
deferral.Complete();
}
}
Multiple ShellContent (or Tab) children inside a TabBar or FlyoutItem produce bottom tabs.
Multiple ShellContent children inside a single Tab produce top tabs:
<Tab Title="Photos">
<ShellContent Title="Recent" ContentTemplate="{DataTemplate views:RecentPage}" />
<ShellContent Title="Favorites" ContentTemplate="{DataTemplate views:FavoritesPage}" />
</Tab>
| Attached Property | Type | Purpose |
|---|---|---|
Shell.TabBarBackgroundColor | Color | Tab bar background |
Shell.TabBarForegroundColor | Color | Selected icon color |
Shell.TabBarTitleColor | Color | Selected tab title color |
Shell.TabBarUnselectedColor | Color | Unselected tab icon/title |
Shell.TabBarIsVisible | bool | Show/hide the tab bar |
<!-- Hide the tab bar on a specific page -->
<ContentPage Shell.TabBarIsVisible="False" ... />
Set on Shell: Disabled, Flyout, or Locked.
<Shell FlyoutBehavior="Flyout"> ... </Shell>
Controls how children appear in the flyout:
AsSingleItem (default) — one flyout entry for the groupAsMultipleItems — each child Tab gets its own entry<FlyoutItem Title="Animals" FlyoutDisplayOptions="AsMultipleItems">
<Tab Title="Cats" ... />
<Tab Title="Dogs" ... />
</FlyoutItem>
<MenuItem Text="Log Out"
Command="{Binding LogOutCommand}"
IconImageSource="logout.png" />
Customize the back button per page:
<Shell.BackButtonBehavior>
<BackButtonBehavior Command="{Binding BackCommand}"
IconOverride="back_arrow.png"
TextOverride="Cancel"
IsVisible="True" />
</Shell.BackButtonBehavior>
Properties: Command, CommandParameter, IconOverride, TextOverride, IsVisible, IsEnabled.
// Current URI location
string location = Shell.Current.CurrentState.Location.ToString();
// Current page
Page page = Shell.Current.CurrentPage;
// Navigation stack of the current tab
IReadOnlyList<Page> stack = Shell.Current.Navigation.NavigationStack;
Override in AppShell:
protected override void OnNavigated(ShellNavigatedEventArgs args)
{
base.OnNavigated(args);
// args.Current, args.Previous, args.Source
}
ShellNavigationSource values: Push, Pop, PopToRoot, Insert, Remove, ShellItemChanged, ShellSectionChanged, ShellContentChanged, Unknown.
Content directly instead of ContentTemplate with DataTemplate creates all pages at Shell init, hurting startup time. Always use ContentTemplate.Routing.RegisterRoute throws ArgumentException if a route name matches an existing route or a visual hierarchy route. Every route must be unique across the app.GoToAsync("somepage") unless somepage was registered with Routing.RegisterRoute. Visual hierarchy pages use absolute // routes.GoToAsync causes race conditions and silent failures. Always await the call.//FlyoutItem/Tab/ShellContent). Wrong paths produce silent no-ops, not exceptions.GoToAsync for all navigation changes.GetDeferral() for async guards: Synchronous cancellation in OnNavigating works, but async checks require GetDeferral() / deferral.Complete() to avoid race conditions.references/shell-navigation-api.md — Full API reference for Shell hierarchy, routes, tabs, flyout, and navigation