WPF:MenuItem内的按钮,关闭菜单

        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="200" Width="300">
    <Grid>
        <Menu>
           <MenuItem Header="File">
               <MenuItem Header="Open" />
               <MenuItem Header="Save" />
               <MenuItem Header="Close" Click="MenuItem_Click" />
            </MenuItem>
        </Menu>
    </Grid>
</Window>

using System.Windows;

namespace WpfApp1
{
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }

        private void MenuItem_Click(object sender, RoutedEventArgs e)
        {
            Close();
        }
    }
}