WPF:如何设置一个Dialog位置显示在应用程序的中心？

private void Dialog_Loaded(object sender, RoutedEventArgs e)
{
    Window parentWindow = Application.Current.MainWindow;
    double left = parentWindow.Left + (parentWindow.Width - this.ActualWidth) / 2;
    double top = parentWindow.Top + (parentWindow.Height - this.ActualHeight) / 2;
    this.Left = left;
    this.Top = top;
}

<Window x:Class="YourNamespace.Dialog"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Dialog" Height="300" Width="400" Loaded="Dialog_Loaded">
    <!-- Dialog的内容和样式 -->
</Window>