在WPF中显示事件的窗口？

<!-- PopupWindow.xaml -->
<Window x:Class="WpfApp.PopupWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Popup Window" Height="200" Width="300">
    <Grid>
        <TextBlock Text="这是一个弹出窗口！" HorizontalAlignment="Center" VerticalAlignment="Center"/>
    </Grid>
</Window>

// PopupWindow.xaml.cs
using System.Windows;

namespace WpfApp
{
    public partial class PopupWindow : Window
    {
        public PopupWindow()
        {
            InitializeComponent();
        }
    }
}

// MainWindow.xaml.cs
using System.Windows;
using System.Windows.Controls;

namespace WpfApp
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void ShowPopupButton_Click(object sender, RoutedEventArgs e)
        {
            PopupWindow popup = new PopupWindow();
            popup.Show();
        }
    }
}