App.xaml.cs

using Hardcodet.Wpf.TaskbarNotification;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Threading.Tasks;
using System.Windows;

namespace WpfApp1
{
    /// <summary>
    /// Interaction logic for App.xaml
    /// </summary>
    public partial class App : Application
    {
        protected override void OnStartup(StartupEventArgs e)
        {
            _taskbar = (TaskbarIcon)FindResource("Taskbar");
            base.OnStartup(e);
        }
        private TaskbarIcon _taskbar;
    }

}