C#のWPFでWindowを閉じる前に確認する

<Window x:Class="Test.TestWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
        xmlns:local="clr-namespace:Test"
        mc:Ignorable="d"
        Closing="Window_Closing">
</Window>

    protected virtual void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e)
    {
        if (MessageBoxResult.Yes != MessageBox.Show("画面を閉じます。よろしいですか？", "確認", MessageBoxButton.YesNo, MessageBoxImage.Information);
        {
            e.Cancel = true;
            return;
        }
    }