private async Task <bool> NavingFromAsync(Portable.INavigatingAwareAsync viewmodel, Page page, object currentParameter, bool suspending, NavigationMode navigationMode, Type targetPageType, object targetParameter)
{
var deferral = new Template10.Mobile.Common.DeferralManager();
var navigatingEventArgs = new Portable.NavigatingEventArgs(deferral)
{
Page = page,
Parameter = currentParameter,
Suspending = suspending,
NavigationMode = navigationMode.ToTemplate10NavigationMode(),
TargetPageType = targetPageType,
TargetPageParameter = targetParameter,
};
try
{
await viewmodel.OnNavigatingFromAsync(navigatingEventArgs);
await deferral.WaitForDeferralsAsync();
}
catch
{
Debugger.Break();
}
return(navigatingEventArgs.Cancel);
}
public async Task NavedToAsync(object viewmodel, object parameter, NavigationMode mode, Page page)
{
Services.NavigationService.NavigationService.DebugWrite();
if (page == null)
{
throw new ArgumentNullException(nameof(page));
}
if (mode == NavigationMode.New)
{
PageState(page).Clear();
}
if (viewmodel == null)
{
return;
}
else if (viewmodel is Classic.INavigatedAwareAsync)
{
var vm = viewmodel as Classic.INavigatedAwareAsync;
await vm?.OnNavigatedToAsync(parameter, mode, PageState(page));
}
else if (viewmodel is Portable.INavigatedAwareAsync)
{
var vm = viewmodel as Portable.INavigatedAwareAsync;
await vm?.OnNavigatedToAsync(parameter, mode.ToTemplate10NavigationMode(), PageState(page));
}
page.InitializeBindings();
page.UpdateBindings();
}
private async Task <bool> NavigationOrchestratorAsync(Type page, object parameter, NavigationMode mode, Func <bool> navigate)
{
DebugWrite($"Page: {page}, Parameter: {parameter}, NavigationMode: {mode}");
if (page == null)
{
throw new ArgumentNullException(nameof(page));
}
if (navigate == null)
{
throw new ArgumentNullException(nameof(navigate));
}
// this cannot be used for duplicate navigation, except for refresh
if ((mode != NavigationMode.Refresh) &&
(page.FullName == CurrentPageType?.GetType().FullName) &&
(parameter?.Equals(CurrentPageParam) ?? false))
{
return(false);
}
// fetch current (which will become old)
var oldPage = FrameFacade.Content as Page;
var oldViewModel = oldPage?.DataContext;
// call oldViewModel.OnNavigatingFromAsync()
var viewmodelCancels = await Navigation.NavingFromCancelsAsync(oldViewModel, oldPage, CurrentPageParam, false, mode, page, parameter);
if (viewmodelCancels)
{
return(false);
}
// raise Navigating event
var eventCancels = RaiseNavigatingCancels(oldPage, parameter, false, mode.ToTemplate10NavigationMode(), page);
if (eventCancels)
{
return(false);
}
// invoke navigate (however custom)
if (navigate.Invoke())
{
CurrentPageParam = parameter;
CurrentPageType = page;
}
else
{
return(false);
}
// fetch (current which is now new)
var newPage = FrameFacade.Content as Page;
var newViewModel = newPage?.DataContext;
// raise Navigated event
RaiseNavigated(newPage, parameter, mode.ToTemplate10NavigationMode());
// call oldViewModel.OnNavigatedFrom()
await Navigation.NavedFromAsync(oldViewModel, oldPage, false);
// call newViewModel.ResolveForPage()
if (newViewModel == null)
{
newPage.DataContext = BootStrapper.Current.ResolveForPage(newPage, this);
}
// call newTemplate10ViewModel.Properties
if (newViewModel is ITemplate10ViewModel)
{
Navigation.SetupViewModel(this, newViewModel as ITemplate10ViewModel);
}
// call newViewModel.OnNavigatedToAsync()
await Navigation.NavedToAsync(newViewModel, parameter, mode, newPage);
// finally
return(true);
}