AppSAV/MauiApp1/App.xaml.cs

using Microsoft.Maui;
using Microsoft.Maui.Controls;
using MauiApp1.Data;

namespace MauiApp1
{
    public partial class App : Application
    {
        private readonly Database _database;

        public App(Database database)
        {
            InitializeComponent();
            _database = database;
            MainPage = new AppShell();
        }

        public static Database Database => Current.Handler.MauiContext.Services.GetService<Database>();
    }
}