| 1 | // Copyright (C) Microsoft Corporation. All rights reserved. |
| 2 | |
| 3 | using Microsoft.UI.Xaml.Controls; |
| 4 | using Microsoft.UI.Xaml.Navigation; |
| 5 | using System.Diagnostics.CodeAnalysis; |
| 6 | using WslSettings.Contracts.Services; |
| 7 | using WslSettings.Contracts.ViewModels; |
| 8 | |
| 9 | namespace WslSettings.Services; |
| 10 | |
| 11 | // For more information on navigation between pages see |
| 12 | // https://github.com/microsoft/TemplateStudio/blob/main/docs/WinUI/navigation.md |
| 13 | public class NavigationService : INavigationService |
| 14 | { |
| 15 | private readonly IPageService _pageService; |
| 16 | private object? _lastParameterUsed; |
| 17 | private Frame? _frame; |
| 18 | |
| 19 | public event NavigatedEventHandler? Navigated; |
| 20 | |
| 21 | public Frame? Frame |
| 22 | { |
| 23 | get |
| 24 | { |
| 25 | return _frame; |
| 26 | } |
| 27 | |
| 28 | set |
| 29 | { |
| 30 | UnregisterFrameEvents(); |
| 31 | _frame = value; |
| 32 | RegisterFrameEvents(); |
| 33 | } |
| 34 | } |
| 35 | |
| 36 | [MemberNotNullWhen(true, nameof(Frame), nameof(_frame))] |
| 37 | public bool CanGoBack => Frame != null && Frame.CanGoBack; |
| 38 | |
| 39 | public NavigationService(IPageService pageService) |
| 40 | { |
| 41 | _pageService = pageService; |
| 42 | } |
| 43 | |
| 44 | private void RegisterFrameEvents() |
| 45 | { |
| 46 | if (_frame != null) |
| 47 | { |
| 48 | _frame.Navigated += OnNavigated; |
| 49 | } |
| 50 | } |
| 51 | |
| 52 | private void UnregisterFrameEvents() |
| 53 | { |
| 54 | if (_frame != null) |
| 55 | { |
| 56 | _frame.Navigated -= OnNavigated; |
| 57 | } |
| 58 | } |
| 59 | |
| 60 | public bool GoBack() |
| 61 | { |
| 62 | if (CanGoBack) |
| 63 | { |
| 64 | var vmBeforeNavigation = _frame.GetPageViewModel(); |
| 65 | _frame.GoBack(); |
| 66 | if (vmBeforeNavigation is INavigationAware navigationAware) |
| 67 | { |
| 68 | navigationAware.OnNavigatedFrom(); |
| 69 | } |
| 70 | |
| 71 | return true; |
| 72 | } |
| 73 | |
| 74 | return false; |
| 75 | } |
| 76 | |
| 77 | public bool NavigateTo(string pageKey, object? parameter = null, bool clearNavigation = false) |
| 78 | { |
| 79 | var pageType = _pageService.GetPageType(pageKey); |
| 80 | |
| 81 | if (_frame != null && (_frame.Content?.GetType() != pageType || (parameter != null && !parameter.Equals(_lastParameterUsed)))) |
| 82 | { |
| 83 | _frame.Tag = clearNavigation; |
| 84 | var vmBeforeNavigation = _frame.GetPageViewModel(); |
| 85 | var navigated = _frame.Navigate(pageType, parameter); |
| 86 | if (navigated) |
| 87 | { |
| 88 | _lastParameterUsed = parameter; |
| 89 | if (vmBeforeNavigation is INavigationAware navigationAware) |
| 90 | { |
| 91 | navigationAware.OnNavigatedFrom(); |
| 92 | } |
| 93 | } |
| 94 | |
| 95 | return navigated; |
| 96 | } |
| 97 | |
| 98 | return false; |
| 99 | } |
| 100 | |
| 101 | private void OnNavigated(object sender, NavigationEventArgs e) |
| 102 | { |
| 103 | if (sender is Frame frame) |
| 104 | { |
| 105 | var clearNavigation = (bool)frame.Tag; |
| 106 | if (clearNavigation) |
| 107 | { |
| 108 | frame.BackStack.Clear(); |
| 109 | } |
| 110 | |
| 111 | if (frame.GetPageViewModel() is INavigationAware navigationAware) |
| 112 | { |
| 113 | navigationAware.OnNavigatedTo(e.Parameter); |
| 114 | } |
| 115 | |
| 116 | Navigated?.Invoke(sender, e); |
| 117 | } |
| 118 | } |
| 119 | } |