public NavigationService(Frame frame)
{
FrameFacade = new FrameFacade(frame);
FrameFacade.Navigating += async(s, e) =>
{
if (e.Suspending)
{
return;
}
// allow the viewmodel to cancel navigation
e.Cancel = !NavigatingFrom(false);
if (!e.Cancel)
{
await NavigateFromAsync(false);
}
};
FrameFacade.Navigated += (s, e) =>
{
NavigateTo(e.NavigationMode, e.Parameter);
};
}
public bool Navigate(Type page, object parameter = null, NavigationTransitionInfo infoOverride = null)
{
if (page == null)
{
throw new ArgumentNullException(nameof(page));
}
if (page.FullName.Equals(LastNavigationType))
{
if (parameter == LastNavigationParameter)
{
return(false);
}
if (parameter != null && parameter.Equals(LastNavigationParameter))
{
return(false);
}
}
parameter = SerializePageParam(parameter);
return(FrameFacade.Navigate(page, parameter, infoOverride));
}
void NavigateTo(NavigationMode mode, object parameter)
{
parameter = DeserializePageParam(parameter);
LastNavigationParameter = parameter;
LastNavigationType = FrameFacade.Content.GetType().FullName;
if (mode == NavigationMode.New)
{
FrameFacade.ClearFrameState();
}
var page = FrameFacade.Content as Page;
if (page != null)
{
if (page.DataContext == null)
{
// to support dependency injection, but keeping it optional.
var viewmodel = BootStrapper.Current.ResolveForPage(page.GetType(), this);
if (viewmodel != null)
{
page.DataContext = viewmodel;
}
}
// call viewmodel
var dataContext = page.DataContext as INavigable;
if (dataContext != null)
{
// prepare for state load
dataContext.NavigationService = this;
dataContext.Dispatcher = WindowWrapper.Current(this)?.Dispatcher;
dataContext.SessionState = BootStrapper.Current.SessionState;
var pageState = FrameFacade.PageStateContainer(page.GetType());
dataContext.OnNavigatedTo(parameter, mode, pageState);
}
}
}
public bool RestoreSavedNavigation()
{
try
{
var state = FrameFacade.PageStateContainer(GetType());
if (state == null || !state.Any() || !state.ContainsKey("CurrentPageType"))
{
return(false);
}
FrameFacade.CurrentPageType = Type.GetType(state["CurrentPageType"].ToString());
FrameFacade.CurrentPageParam = DeserializePageParam(state["CurrentPageParam"]?.ToString());
FrameFacade.SetNavigationState(state["NavigateState"]?.ToString());
NavigateTo(NavigationMode.Refresh, FrameFacade.CurrentPageParam);
while (Frame.Content == null)
{
Task.Yield().GetAwaiter().GetResult();
}
AfterRestoreSavedNavigation?.Invoke(this, FrameFacade.CurrentPageType);
return(true);
}
catch { return(false); }
}
public void GoForward()
{
FrameFacade.GoForward();
}
public void Refresh()
{
FrameFacade.Refresh();
}
