public void GoForward()
{
if (CanGoForward)
{
InnerNavigate(ForwardStack.Last(), NavigationMode.Forward);
}
}
public void ClearHistory(int level)
{
ForwardStack.Clear();
while (BackStack.Count > level)
{
BackStack.RemoveAt(level);
}
}
//[IsKeepAlive() moved to NavigationService.IsContentKeepAlive()]
internal void UpdateView()
{
BackStack.OnCollectionChanged();
ForwardStack.OnCollectionChanged();
if (_backForwardStateChange != null)
{
_backForwardStateChange(this, EventArgs.Empty);
}
}
private async Task GoBackAsync()
{
BackStack.Remove(CurrentItem);
ForwardStack.Add(CurrentItem);
if (BackStack.Count > 0)
{
CurrentItem = BackStack.Last();
}
await ReloadAsync();
}
private async Task GoForwardAsync()
{
if (ForwardStack.Count > 0)
{
CurrentItem = ForwardStack.Last();
}
ForwardStack.Remove(CurrentItem);
BackStack.Add(CurrentItem);
await ReloadAsync();
}
private void AddToForwardStack(
IViewModel viewModel,
FrameworkElement content)
{
var origin = new WeakNavigationStackEntry(
viewModel,
content);
ForwardStack.Add(origin);
}
public Frame()
{
var backStack = new ObservableCollection <PageStackEntry>();
var forwardStack = new ObservableCollection <PageStackEntry>();
backStack.CollectionChanged += (s, e) => CanGoBack = BackStack.Any();
forwardStack.CollectionChanged += (s, e) => CanGoForward = ForwardStack.Any();
BackStack = backStack;
ForwardStack = forwardStack;
}
public void GoForward()
{
if (CurrentItem != null)
{
BackStack.Push(CurrentItem);
}
if (ForwardStack.Count > 0)
{
CurrentItem = ForwardStack.Pop();
}
OnStackChanged();
}
public void Resume(Stream stream, Navigator navigator)
{
var deserializer = new DataContractJsonSerializer(typeof(FrameStack), new DataContractJsonSerializerSettings());
var stack = (FrameStack)deserializer.ReadObject(stream);
navigator.ToUrl(stack.Current);
foreach (var item in stack.Back)
{
BackStack.Add(new PageStackEntry(typeof(MainPage), item, null));
}
foreach (var item in stack.Forward)
{
ForwardStack.Add(new PageStackEntry(typeof(MainPage), item, null));
}
}
public Frame()
{
var backStack = new ObservableCollection <PageStackEntry>();
var forwardStack = new ObservableCollection <PageStackEntry>();
backStack.CollectionChanged += (s, e) =>
{
CanGoBack = BackStack.Any();
BackStackDepth = BackStack.Count;
};
forwardStack.CollectionChanged += (s, e) => CanGoForward = ForwardStack.Any();
BackStack = backStack;
ForwardStack = forwardStack;
DefaultStyleKey = typeof(Frame);
}
private void HandleContentNavigating(object sender, NavigatingCancelEventArgs e)
{
if (IsNavigating)
{
return;
}
IsNavigating = true;
// Choose the name of the transition based on the e.ExtraData that was passed to NavigationService.Navigate().
// If the data is a string, we'll try to find a matching transition by that name.
if (e.ExtraData is ResolvedNavigationRequest)
{
var transitionName = ((ResolvedNavigationRequest)e.ExtraData).RouteValues.GetOrDefault <string>("Transition");
CurrentTransition = transitionRegistry.Get(transitionName);
}
else if (e.ExtraData is string && transitionRegistry.Get(e.ExtraData.ToString()) != null)
{
var transitionName = e.ExtraData.ToString();
CurrentTransition = transitionRegistry.Get(transitionName);
}
else
{
CurrentTransition = null;
}
// Keep a record of back/forward navigation and use this to select the reverse transitions.
if (e.NavigationMode == NavigationMode.New)
{
BackStack.Push(CurrentTransition);
}
else if (e.NavigationMode == NavigationMode.Back)
{
var original = BackStack.Pop();
ForwardStack.Push(original);
var reverseTransition = original == null ? null : transitionRegistry.Get(original.Reverse);
CurrentTransition = reverseTransition;
}
else if (e.NavigationMode == NavigationMode.Forward)
{
CurrentTransition = ForwardStack.Pop();
BackStack.Push(CurrentTransition);
}
}
public bool TryGoForward()
{
if (!CanGoForward)
{
return(false);
}
var destination = ForwardStack.LastOrDefault();
if (destination == null)
{
return(false);
}
if (!destination.ViewModel.TryGetTarget(
out var viewModel))
{
return(false);
}
if (!destination.Content.TryGetTarget(
out var content))
{
return(false);
}
ForwardStack.Remove(destination);
AddToBackStack(
viewModel,
content);
SetCurrent(
viewModel,
content);
return(true);
}
public async Task NavigateAsync(DavItem item)
{
if (item == null)
{
return;
}
if (BackStack.FirstOrDefault(x => x.EntityId == item.EntityId) != null)
{
var backStackItem = BackStack.FirstOrDefault(x => x.EntityId == item.EntityId);
int index = BackStack.IndexOf(backStackItem);
var list = BackStack.ToList();
list.RemoveRange(index + 1, BackStack.Count - index - 1);
BackStack = list.ToObservableCollection();
ForwardStack.Clear();
CurrentItem = backStackItem;
}
else
{
BackStack.Add(item);
ForwardStack.Remove(item);
CurrentItem = item;
}
await ReloadAsync();
}
private bool InnerNavigate(PageStackEntry entry, NavigationMode mode)
{
try
{
// Navigating
var navigatingFromArgs = new NavigatingCancelEventArgs(
mode,
entry.NavigationTransitionInfo,
entry.Parameter,
entry.SourcePageType
);
Navigating?.Invoke(this, navigatingFromArgs);
CurrentEntry?.Instance.OnNavigatingFrom(navigatingFromArgs);
if (navigatingFromArgs.Cancel)
{
NavigationStopped?.Invoke(this, new NavigationEventArgs(
entry.Instance,
mode,
entry.NavigationTransitionInfo,
entry.Parameter,
entry.SourcePageType,
null
));
return(false);
}
// Navigate
var previousEntry = CurrentEntry;
CurrentEntry = entry;
if (mode == NavigationMode.New)
{
// Doing this first allows CurrentEntry to reuse existing page if pooling is enabled
ReleasePages(ForwardStack);
}
if (CurrentEntry.Instance == null)
{
var page = CreatePageInstanceCached(entry.SourcePageType);
if (page == null)
{
return(false);
}
page.Frame = this;
CurrentEntry.Instance = page;
}
Content = CurrentEntry.Instance;
switch (mode)
{
case NavigationMode.New:
ForwardStack.Clear();
if (previousEntry != null)
{
BackStack.Add(previousEntry);
}
break;
case NavigationMode.Back:
ForwardStack.Add(previousEntry);
BackStack.Remove(CurrentEntry);
break;
case NavigationMode.Forward:
BackStack.Add(previousEntry);
ForwardStack.Remove(CurrentEntry);
break;
case NavigationMode.Refresh:
break;
}
// Navigated
var navigationEvent = new NavigationEventArgs(
CurrentEntry.Instance,
mode,
entry.NavigationTransitionInfo,
entry.Parameter,
entry.SourcePageType,
null
);
previousEntry?.Instance.OnNavigatedFrom(navigationEvent);
CurrentEntry.Instance.OnNavigatedTo(navigationEvent);
Navigated?.Invoke(this, navigationEvent);
VisualTreeHelper.CloseAllPopups();
return(true);
}
catch (Exception exception)
{
NavigationFailed?.Invoke(this, new NavigationFailedEventArgs(entry.SourcePageType, exception));
return(false);
}
}
