系统异常，未检测到已安装的组件

Question

我开始学习C＃，这是我的第一次练习。我得到System.Exception。我不知道它是什么，Visual Studio 2013也说没有安装该组件。我检查了代码是否存在语法错误。

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, propertyToAnimate);
    storyboard.Children.Add(animation);
    storyboard.Begin();
}