MainPage.xaml.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices.WindowsRuntime;
using Windows.Foundation;
using Windows.Foundation.Collections;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Controls.Primitives;
using Windows.UI.Xaml.Data;
using Windows.UI.Xaml.Input;
using Windows.UI.Xaml.Media.Imaging;
using Windows.UI.Xaml.Navigation;
using Waher.Events;
using Waher.Mock;
using System.Threading.Tasks;
 
namespace Waher.Mock.Lamp.UWP
{
    public sealed partial class MainPage : Page
    {
        private static ListViewSniffer sniffer = null;
        private static ListViewEventSink eventSink = null;
        private static MainPage instance = null;
 
        public MainPage()
        {
            this.InitializeComponent();
 
            if (sniffer is null)
                sniffer = new ListViewSniffer(this.SnifferListView);
 
            if (eventSink is null)
            {
                eventSink = new ListViewEventSink("List View Event Sink.", this.EventsListView);
                Log.Register(eventSink);
            }
 
            if (instance is null)
                instance = this;
 
            App.OwnershipChanged += this.App_OwnershipChanged;
        }
 
        private Task App_OwnershipChanged(object Sender, EventArgs e)
        {
            if (string.IsNullOrEmpty(App.OwnerJid))
            {
                this.OwnerLabel.Visibility = Visibility.Collapsed;
                this.Owner.Visibility = Visibility.Collapsed;
                this.QrCodeLabel.Visibility = Visibility.Visible;
                this.QrCode.Source = new BitmapImage(new Uri(App.QrCodeUrl));
                this.QrCode.Visibility = Visibility.Visible;
            }
            else
            {
                this.OwnerLabel.Visibility = Visibility.Visible;
                this.Owner.Text = App.OwnerJid;
                this.Owner.Visibility = Visibility.Visible;
                this.QrCodeLabel.Visibility = Visibility.Collapsed;
                this.QrCode.Visibility = Visibility.Collapsed;
            }
 
            return Task.CompletedTask;
        }
 
        private void Page_Unloaded(object _, RoutedEventArgs __)
        {
            if (!(sniffer is null) && sniffer.ListView == this.SnifferListView)
                sniffer = null;
 
            if (!(eventSink is null) && eventSink.ListView == this.EventsListView)
            {
                Log.Unregister(eventSink);
                eventSink.Dispose();
                eventSink = null;
            }
 
            if (instance == this)
                instance = null;
        }
 
        public static ListViewSniffer Sniffer
        {
            get { return sniffer; }
        }
 
        public static MainPage Instance
        {
            get { return instance; }
        }
    }
}