/// <summary>
/// Navigates to the current page type defined in <see cref="CurrentPageType"/>.
/// </summary>
/// <param name="mode">The navigation mode.</param>
/// <param name="parameter">The parameter.</param>
internal void NavigateTo(NavigationMode mode, object parameter)
{
_lastNavigationParameter = parameter;
_lastNavigationType = FrameFacade.Content.GetType().FullName;
// clears the frame state when a page is newly navigated (not just refreshed or back navigated)
if (mode == NavigationMode.New)
{
FrameFacade.ClearFrameState();
}
var page = FrameFacade.Content as Page;
if (page != null)
{
// call viewmodel
var dataContext = page.DataContext as INavigable;
if (dataContext != null)
{
// prepare for state load
dataContext.NavigationService = this;
var pageState = FrameFacade.GetPageStateContainer(page.GetType());
dataContext.OnNavigatedTo(parameter, mode, pageState);
}
}
}
/// <summary>
/// Navigate from that is called after navigation.
/// </summary>
/// <param name="suspending">The suspending flag.</param>
internal async Task NavigateFromAsync(bool suspending)
{
var page = FrameFacade.Content as Page;
if (page != null)
{
// call viewmodel
var dataContext = page.DataContext as INavigable;
if (dataContext != null)
{
var pageState = FrameFacade.GetPageStateContainer(page.GetType());
await dataContext.OnNavigatedFromAsync(pageState, suspending);
}
}
}
/// <summary>
/// Restores the saved navigation state.
/// </summary>
/// <returns>Returns True for success, else False.</returns>
public bool RestoreSavedNavigation()
{
try
{
var state = FrameFacade.GetPageStateContainer(GetType());
if (state == null || !state.Any() || !state.ContainsKey(CURRENT_PAGE_TYPE_KEY))
{
return(false);
}
string currentPageType = state[CURRENT_PAGE_TYPE_KEY].ToString();
Type pageTypeOfAppAssembly = Type.GetType(string.Format("{0}, {1}", currentPageType, UniversalApp.AppAssemblyName));
FrameFacade.CurrentPageType = pageTypeOfAppAssembly;
FrameFacade.CurrentPageParam = state[CURRENT_PAGE_PARAM_KEY];
FrameFacade.SetNavigationState(state[NAVIGATE_STATE_KEY].ToString());
while (FrameFacade.Frame.Content == null) /* wait */ } {
AfterRestoreSavedNavigation?.Invoke(this, FrameFacade.CurrentPageType);
return(true);
}
/// <summary>
/// Save the navigation state.
/// </summary>
public void SaveNavigation()
{
// it is possible to close the application before we have navigated and created state
if (CurrentPageType == null)
{
return;
}
var state = FrameFacade.GetPageStateContainer(GetType());
if (state == null)
{
throw new InvalidOperationException("State container is unexpectedly null");
}
state[CURRENT_PAGE_TYPE_KEY] = CurrentPageType.ToString();
try { state[CURRENT_PAGE_PARAM_KEY] = CurrentPageParam; }
catch
{
throw new Exception("Failed to serialize page parameter, override/implement ToString()");
}
state[NAVIGATE_STATE_KEY] = FrameFacade?.GetNavigationState();
}
