PrismLibrary/Prism · error · NavigationException

Cannot process an absolute Navigation Uri when navigating…

Error message

Cannot process an absolute Navigation Uri when navigating within a specified Tab

What it means

Prism's PageNavigationService throws this when you ask SelectTabAsync to navigate using an absolute URI (e.g. ':///MyPage' or 'https://app/MyPage') while targeting a tab of an existing TabbedPage. Tab-level navigation only supports relative segments because it operates on an already-resolved child page inside the tab, not the root navigation stack.

Solutions

1. Use a relative URI or page name for tab navigation, e.g. 'ViewA?id=5' instead of 'app://.../ViewA?id=5'
2. Strip the scheme/host from your deep link before passing it to tab navigation: new Uri(link).PathAndQuery trimmed of leading '/'
3. Handle absolute deep links at the app root (NavigateAsync) and reserve tab selection for relative segments

Example fix

// before
await _navigationService.SelectTabAsync(new Uri("app:///ViewB"), tabbedPage, "ViewB");
// after
await _navigationService.SelectTabAsync("ViewB", tabbedPage, "ViewB");

if (uri is not null && uri.IsAbsoluteUri)
    throw new ArgumentException("Use a relative URI for tab navigation");

static bool IsRelativeNavUri(Uri? uri) => uri is null || !uri.IsAbsoluteUri;

When it happens

Trigger: Calling navigationService.SelectTabAsync(uri, tabbedPage, selectedTab, parameters) (directly or via a tab-select URI segment) with a uri whose IsAbsoluteUri is true.

Common situations: Passing a full deep-link URI into a tab-selection flow; concatenating an app scheme root onto a tab path; reusing a deep-link handler that always builds absolute URIs when the user taps a tab.

Understand the failure class

Background: "Invalid URL" errors: why new URL(), URI.parse, and reqwest::Url reject your string — missing scheme, whitespace, and bad path format — this error's family across 39 libraries.

Related errors

• The page type ' ' is not supported.
• Unable to determine the current page.
• NavigationException.NoPageIsRegistered
• The builder does not implement IRegistryAware
• NavigationException.NoPageIsRegistered

AI-assisted analysis of PrismLibrary/Prism@358118cd64 (2026-09-15). Data as JSON: /api/errors/22dfa3c4eb8b6075. Report an issue: GitHub.

Appendix: source

Thrown at src/Maui/Prism.Maui/Navigation/PageNavigationService.cs:411

                    && (ViewModelLocator.GetNavigationName(navPage) == parts[0] || (rootRegistration is not null && IsPage(navPage, rootRegistration, parts[0])))
                    && (ViewModelLocator.GetNavigationName(navPage.RootPage) == parts[1] || (leafRegistration is not null && IsPage(navPage.RootPage, leafRegistration, parts[1]))));
            }
            else
                throw new NavigationException($"Invalid Tab Name: {tabName}");

            if (selectedChild is null)
                throw new NavigationException($"No Tab found with the Name: {tabName}");

            var navigatedFromPage = _pageAccessor.Page;
            if (!await MvvmHelpers.CanNavigateAsync(navigatedFromPage, parameters))
                throw new NavigationException(NavigationException.IConfirmNavigationReturnedFalse, navigatedFromPage);

            var navigatedToTarget = selectedChild is NavigationPage navPage ? navPage.CurrentPage : selectedChild;
            if (uri is not null)
            {
                if (uri.IsAbsoluteUri)
                {
                    throw new NavigationException("Cannot process an absolute Navigation Uri when navigating within a specified Tab");
                }

                var navigationSegments = UriParsingHelper.GetUriSegments(uri);
                await ProcessNavigation(navigatedToTarget, navigationSegments, parameters, null, null);
                tabbedPage.CurrentPage = selectedChild;
            }
            else
            {
                tabbedPage.CurrentPage = selectedChild;
                parameters.GetNavigationParametersInternal().Add(KnownInternalParameters.NavigationMode, NavigationMode.New);
                MvvmHelpers.OnNavigatedFrom(navigatedFromPage, parameters);
                MvvmHelpers.OnNavigatedTo(navigatedToTarget, parameters);
            }

            return new NavigationResult();
        }
        catch (Exception ex)
        {

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