有没有办法回到导航堆栈的最后一页，而不是在 Xamarin 中执行 OnApearing 方法？

Question

So, I have Page1 , with some input fields that my user already filled, and, there is a button that opens a new Page (let's call it Page2 ).

This is the code I used to go on Page2 .

Application.Current.MainPage.Navigation.PushModalAsync(new NavigationPage(new Page2()));

This is the code I used to came back on Page1 .

private async void GoBackButton_Clicked(object sender, EventArgs e)
    {
        await Application.Current.MainPage.Navigation.PopModalAsync();
    }

Now, I'd like to, somehow, when user finishes what he had on Page2 , he presses the button, called GoBack , then he comes back on the Page1 , and the OnApearing method of Page1 's ViewModel is NOT getting executed. Is this doable?

Not sure if important, but I'm using VS22, on Windows10.

Answer 1

This is what I'm using in some of my apps. The logic is: Page1 loads data on the first load and then only reloads data when reload requested.

Here's an example:

Page1.xaml.cs

public partial class Page1 : ContentPage
{
    private bool _isFirstLoad = true;
    private bool _isReloadRequested;

    public Page1()
    {
        InitializeComponent();
    }

    private async Task OpenPage2Async()
    {
        //navigate to Page2
        await Application.Current.MainPage.Navigation.PushModalAsync(new NavigationPage(new Page2(() => _isReloadRequested = true)));
    }

    protected override void OnAppearing()
    {
        if (_isFirstLoad)
        {
            _isFirstLoad = false;
            ReloadData();
            return;
        }

        if (_isReloadRequested)
        {
            ReloadData();
            _isReloadRequested = false;
        }
    }

    private void ReloadData()
    {
        //reload data...
    }
}

Page2.xaml.cs

public partial class Page2 : ContentPage
{
    private readonly Action _requestReload;

    public Page2(Action requestReload)
    {
        InitializeComponent();
        _requestReload = requestReload;
    }

    private async Task GoBackAsync()
    {
        //invoke callback to set Page1's _isReloadRequested to true
        _requestReload?.Invoke();
        //go back to Page1
        await Application.Current.MainPage.Navigation.PopModalAsync();
    }
}