Auto dismiss Login page when logged

Question

I have the following page navigation in my app:

AnyPage -> Login -> Register

When the user gets registered he is automatically logged to. So I want the Login page to be closed automatically if the user go back to it and is logged.

I tried to add some code to the LoginPage.onNavigatedTo method but it doesn't work.

    protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        this.navigationHelper.OnNavigatedTo(e);
        if(AccountController.isLogged()){
            Frame.GoBack();
        }
    }

How can I do it?

Answer 1

The OnNavigatedTo and OnNavigatedFrom methods are part of the ongoing navigation operation. When you try to start a new navigation while there is one in progress, navigation methods will stop and return false.

Simple trick is: Make your OnNavigatedTo async and add a delay before navigating back.

protected override async void OnNavigatedTo(NavigationEventArgs e)
{
    this.navigationHelper.OnNavigatedTo(e);
    if(AccountController.isLogged()){
        await Task.Delay(1);
        Frame.GoBack();
    }
}

The reason this works is: Navigation is handled on the UI Thread. As the Event Methods are void returning, they are not awaited and if you return a task inside of them, the current caller finishes his current task. Whatever comes after the await is queued to the Dispatcher and finished once he has time for it (which is immediately after the navigation operation finishes).