private async Task OnNavigatingFromAsync(NavigatingCancelEventArgs e, IHandleNavigatingFrom handler)
{
var navigationServiceNavigatingCancelEventArgs = e.ToNavigationServiceNavigatingCancelEventArgs();
await InvokeHandlerOnNavigatingFromAsync(handler, navigationServiceNavigatingCancelEventArgs);
if (!navigationServiceNavigatingCancelEventArgs.Cancel)
{
_alreadyPerformedOnNavigatingFrom = true;
#if WINDOWS_PHONE || WINDOWS_PHONE_81
Dispatcher.BeginInvoke(() =>
{
var frame = this.GetVisualAncestor <Frame>();
switch (e.NavigationMode)
{
case NavigationMode.New:
frame.Navigate(e.Uri);
break;
#else
await Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
{
var frame = this.Frame;
switch (e.NavigationMode)
{
case NavigationMode.New:
frame.Navigate(e.SourcePageType, e.Parameter, e.NavigationTransitionInfo);
break;
#endif
case NavigationMode.Back:
frame.GoBack();
break;
case NavigationMode.Forward:
frame.GoForward();
break;
}
});
}
}
}
}
private async Task OnNavigatingFromAsync(NavigatingCancelEventArgs e, IHandleNavigatingFrom handler)
{
var navigationServiceNavigatingCancelEventArgs = e.ToNavigationServiceNavigatingCancelEventArgs();
await InvokeHandlerOnNavigatingFromAsync(handler, navigationServiceNavigatingCancelEventArgs);
if (!navigationServiceNavigatingCancelEventArgs.Cancel)
{
_alreadyPerformedOnNavigatingFrom = true;
#if WINDOWS_PHONE || WINDOWS_PHONE_81
Dispatcher.BeginInvoke(() =>
{
var frame = this.GetVisualAncestor<Frame>();
switch (e.NavigationMode)
{
case NavigationMode.New:
frame.Navigate(e.Uri);
break;
#else
await Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
{
var frame = this.Frame;
switch (e.NavigationMode)
{
case NavigationMode.New:
frame.Navigate(e.SourcePageType, e.Parameter, e.NavigationTransitionInfo);
break;
#endif
case NavigationMode.Back:
frame.GoBack();
break;
case NavigationMode.Forward:
frame.GoForward();
break;
}
});
}
}
}
}
/// <summary> /// Invokes the <see cref="IHandleNavigatingFrom.OnNavigatingFromAsync"/> for the current <see cref="FrameworkElement.DataContext"/>. /// </summary> /// <param name="handler">The <see cref="IHandleNavigatingFrom"/> instance.</param> /// <param name="e">An object that contains the event data.</param> /// <returns>The <see cref="Task"/> object representing the asynchronous operation.</returns> protected virtual Task InvokeHandlerOnNavigatingFromAsync(IHandleNavigatingFrom handler, NavigationServiceNavigatingCancelEventArgs e) => handler.OnNavigatingFromAsync(e);
/// <summary> /// Invokes the <see cref="IHandleNavigatingFrom.OnNavigatingFromAsync"/> for the current <see cref="FrameworkElement.DataContext"/>. /// </summary> /// <param name="handler">The <see cref="IHandleNavigatingFrom"/> instance.</param> /// <param name="e">An object that contains the event data.</param> /// <returns>The <see cref="Task"/> object representing the asynchronous operation.</returns> protected virtual Task InvokeHandlerOnNavigatingFromAsync(IHandleNavigatingFrom handler, NavigationServiceNavigatingCancelEventArgs e) => handler.OnNavigatingFromAsync(e);
