public void PropertyChanged_CanGoBack_IsNotCalledWheNavigatingBackToFirstPage()
{
NavigationStack navigationStack = new NavigationStack();
navigationStack.NavigateTo(new PageInfo("Page 1", null));
navigationStack.NavigateTo(new PageInfo("Page 2", null));
navigationStack.NavigateTo(new PageInfo("Page 3", null));
int changedCount = 0;
navigationStack.PropertyChanged += delegate (object sender, PropertyChangedEventArgs e) { if (e.PropertyName == "CanGoBack") changedCount++; };
navigationStack.GoBackTo(navigationStack[0]);
Assert.Equal(0, changedCount);
}
public void NavigatingFrom_IsCalledWhenNavigatingBackToAPage()
{
NavigationStack navigationStack = new NavigationStack();
navigationStack.NavigateTo(new PageInfo("Page 1", null));
navigationStack.NavigateTo(new PageInfo("Page 2", null));
navigationStack.NavigateTo(new PageInfo("Page 3", null));
List<PageNavigationEventArgs> navigationEvents = new List<PageNavigationEventArgs>();
navigationStack.NavigatingFrom += delegate (object sender, PageNavigationEventArgs e) { navigationEvents.Add(e); };
navigationStack.GoBackTo(navigationStack[0]);
Assert.Equal(1, navigationEvents.Count);
PageNavigationEventArgs navigationEvent = navigationEvents[0];
Assert.Equal(PageNavigationMode.Back, navigationEvent.NavigationMode);
Assert.Equal("Page 3", navigationEvent.Page.PageName);
}
public void PageDisposed_IsCalledWhenNavigatingBackMultiplePages()
{
NavigationStack navigationStack = new NavigationStack();
navigationStack.NavigateTo(new PageInfo("Page 1", null));
navigationStack.NavigateTo(new PageInfo("Page 2", null));
navigationStack.NavigateTo(new PageInfo("Page 3", null));
List<PageNavigationEventArgs> pageDisposedEvents = new List<PageNavigationEventArgs>();
navigationStack.PageDisposed += delegate (object sender, PageNavigationEventArgs e) { pageDisposedEvents.Add(e); };
navigationStack.GoBackTo(navigationStack[0]);
Assert.Equal(2, pageDisposedEvents.Count);
PageNavigationEventArgs pageDisposedEventPage2 = pageDisposedEvents.First(e => e.Page.PageName == "Page 2");
PageNavigationEventArgs pageDisposedEventPage3 = pageDisposedEvents.First(e => e.Page.PageName == "Page 3");
Assert.Equal(PageNavigationMode.Back, pageDisposedEventPage2.NavigationMode);
Assert.Equal("Page 2", pageDisposedEventPage2.Page.PageName);
Assert.Equal(PageNavigationMode.Back, pageDisposedEventPage3.NavigationMode);
Assert.Equal("Page 3", pageDisposedEventPage3.Page.PageName);
}
public void CollectionChanged_IsCalledWhenNavigatingBackTo_OnPage()
{
NavigationStack navigationStack = new NavigationStack();
navigationStack.NavigateTo(new PageInfo("Page 1", null));
navigationStack.NavigateTo(new PageInfo("Page 2", null));
navigationStack.NavigateTo(new PageInfo("Page 3", null));
List<NotifyCollectionChangedEventArgs> changeEvents = new List<NotifyCollectionChangedEventArgs>();
navigationStack.CollectionChanged += delegate (object sender, NotifyCollectionChangedEventArgs e) { changeEvents.Add(e); };
navigationStack.GoBackTo(navigationStack[1]);
Assert.Equal(1, changeEvents.Count);
NotifyCollectionChangedEventArgs changeEvent = changeEvents[0];
Assert.Equal(NotifyCollectionChangedAction.Remove, changeEvent.Action);
Assert.Equal(1, changeEvent.OldItems.Count);
Assert.Equal("Page 3", ((PageInfo)changeEvent.OldItems[0]).PageName);
Assert.Equal(2, changeEvent.OldStartingIndex);
}
public void CollectionChanged_IsCalledWhenNavigatingBackTo_MultiplePages()
{
NavigationStack navigationStack = new NavigationStack();
navigationStack.NavigateTo(new PageInfo("Page 1", null));
navigationStack.NavigateTo(new PageInfo("Page 2", null));
navigationStack.NavigateTo(new PageInfo("Page 3", null));
List<NotifyCollectionChangedEventArgs> changeEvents = new List<NotifyCollectionChangedEventArgs>();
navigationStack.CollectionChanged += delegate (object sender, NotifyCollectionChangedEventArgs e) { changeEvents.Add(e); };
navigationStack.GoBackTo(navigationStack[0]);
Assert.Equal(1, changeEvents.Count);
NotifyCollectionChangedEventArgs changeEvent = changeEvents[0];
Assert.Equal(NotifyCollectionChangedAction.Reset, changeEvent.Action);
}
public void GoBackTo_ThrowsException_NullPage()
{
NavigationStack navigationStack = new NavigationStack();
var e = Assert.Throws<ArgumentNullException>(() => navigationStack.GoBackTo(null));
Assert.Equal("Value cannot be null.\r\nParameter name: page", e.Message);
Assert.Equal("page", e.ParamName);
}
public void GoBackTo_ThrowsException_SpecifiedPageNotInBackStack()
{
NavigationStack navigationStack = new NavigationStack();
navigationStack.NavigateTo(new PageInfo("Page 1", null));
navigationStack.NavigateTo(new PageInfo("Page 2", null));
PageInfo unknownPage = new PageInfo("Page 3", null);
var e = Assert.Throws<InvalidOperationException>(() => navigationStack.GoBackTo(unknownPage));
Assert.Equal("The specified page 'Page 3' does not exist in the navigation stack.", e.Message);
}
public void GoBackTo_NavigatesBackToSpecifiedPage()
{
NavigationStack navigationStack = new NavigationStack();
PageInfo page2 = new PageInfo("Page 2", null);
navigationStack.NavigateTo(new PageInfo("Page 1", null));
navigationStack.NavigateTo(page2);
navigationStack.NavigateTo(new PageInfo("Page 3", null));
navigationStack.NavigateTo(new PageInfo("Page 4", null));
navigationStack.GoBackTo(page2);
Assert.Equal(2, navigationStack.Count);
Assert.Equal("Page 1", navigationStack[0].PageName);
Assert.Equal("Page 2", navigationStack[1].PageName);
}
