Wino-Mail/Wino.Core.UWP/BasePage.cs

using System;
using System.Diagnostics;
using CommunityToolkit.Mvvm.Messaging;
using Microsoft.Extensions.DependencyInjection;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Navigation;
using Wino.Core.ViewModels;
using Wino.Messaging.Client.Shell;

namespace Wino.Core.UWP;

public partial class BasePage : Page, IRecipient<LanguageChanged>
{
    public UIElement ShellContent
    {
        get { return (UIElement)GetValue(ShellContentProperty); }
        set { SetValue(ShellContentProperty, value); }
    }

    public static readonly DependencyProperty ShellContentProperty = DependencyProperty.Register(nameof(ShellContent), typeof(UIElement), typeof(BasePage), new PropertyMetadata(null));

    public void Receive(LanguageChanged message)
    {
        OnLanguageChanged();
    }

    public virtual void OnLanguageChanged() { }
}

public abstract class BasePage<T> : BasePage where T : CoreBaseViewModel
{
    public T ViewModel { get; } = WinoApplication.Current.Services.GetService<T>();

    protected BasePage()
    {
        ViewModel.Dispatcher = new UWPDispatcher(Dispatcher);

        Loaded += PageLoaded;
        Unloaded += PageUnloaded;
    }

    private void PageUnloaded(object sender, RoutedEventArgs e)
    {
        Loaded -= PageLoaded;
        Unloaded -= PageUnloaded;
    }

    private void PageLoaded(object sender, RoutedEventArgs e) => ViewModel.OnPageLoaded();

    ~BasePage()
    {
        Debug.WriteLine($"Disposed {GetType().Name}");
    }

    protected override void OnNavigatedTo(NavigationEventArgs e)
    {
        base.OnNavigatedTo(e);

        var mode = GetNavigationMode(e.NavigationMode);
        var parameter = e.Parameter;

        WeakReferenceMessenger.Default.UnregisterAll(this);
        WeakReferenceMessenger.Default.RegisterAll(this);

        ViewModel.OnNavigatedTo(mode, parameter);
    }

    protected override void OnNavigatingFrom(NavigatingCancelEventArgs e)
    {
        base.OnNavigatingFrom(e);

        var mode = GetNavigationMode(e.NavigationMode);
        var parameter = e.Parameter;

        WeakReferenceMessenger.Default.UnregisterAll(this);

        ViewModel.OnNavigatedFrom(mode, parameter);

        GC.Collect();
    }

    private Domain.Models.Navigation.NavigationMode GetNavigationMode(NavigationMode mode)
    {
        return (Domain.Models.Navigation.NavigationMode)mode;
    }
}