WPF ошибка CS1061 с ссылкой на XAML-файл

Вот код С#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Windows.Threading;

namespace WpfApp2
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainPage : Window
    {
        Random random = new Random();
        DispatcherTimer enemyTimer = new DispatcherTimer();
        DispatcherTimer targetTimer = new DispatcherTimer();
        bool humanCaptured = false;
        public MainPage()
        {
            InitializeComponent();
            enemyTimer.Tick += enemyTimer_Tick;
            enemyTimer.Interval = TimeSpan.FromSeconds(2);
            targetTimer.Tick += targetTime_Tick;
            targetTimer.Interval = TimeSpan.FromSeconds(.1);
        }
        private void targetTime_Tick(object sender, object e)
        {
            progressBar.Value += 1;
            if (progressBar.Value >= progressBar.Maximum)
            {
                EndTheGame();
            }
        }
        private void EndTheGame()
        {
            if (!playArea.Children.Contains(gameOverText))
            {
                enemyTimer.Stop();
                targetTimer.Stop();
                humanCaptured = false;
                StartButton.Visibility = Visibility.Visible;
                playArea.Children.Add(gameOverText);
            }
        }
        private void enemyTimer_Tick(object sender, object e)
        {
        }
        private void StartButton_Click(object sender, RoutedEventArgs e)
        {
            AddEnemy();
        }
        private void AddEnemy()
        {
            ContentControl enemy = new ContentControl();
            enemy.Template = Resources["EnemyTemplate"] as ControlTemplate;
            AnimateEnemy(enemy, 0, playArea.ActualWidth - 100, "(Canvas.Left)");
            AnimateEnemy(enemy, random.Next((int)playArea.ActualHeight - 100),
                random.Next((int)playArea.ActualHeight - 100), "(Canvas.Top)");
            playArea.Children.Add(enemy);
        }
        private void AnimateEnemy(ContentControl enemy, double from, double to, string propertyToAnimate)
        {
            Storyboard storyboard = new Storyboard { AutoReverse = true, RepeatBehavior = RepeatBehavior.Forever };
            DoubleAnimation animation = new DoubleAnimation()
            {
                From = from,
                To = to,
                Duration = new Duration(TimeSpan.FromSeconds(random.Next(4, 6)))
            };
            Storyboard.SetTarget(animation, enemy);
            Storyboard.SetTargetProperty(animation, new PropertyPath(propertyToAnimate));
            storyboard.Children.Add(animation);
            storyboard.Begin();
        }
    }
}

А вот это часть на которую ссылается ошибка

<ProgressBar x:Name="progressBar" Grid.Column="1" Grid.Row="2" Height="20" ValueChanged="ProgressBar_ValueChanged"/>

Сама ошибка на скриншоте или вот текстом:

Error CS1061 'MainPage' does not contain a definition for 'ProgressBar_ValueChanged' and no accessible extension method 'ProgressBar_ValueChanged' accepting a first argument of type 'MainPage' could be found (are you missing a using directive or an assembly reference?)

Новая ошибка