WPF 窗体中获取键盘和鼠标无操作时的超时提示

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using System.Runtime.InteropServices;

namespace WpfApplication1
{
    /// 

    /// Window1.xaml 的交互逻辑
    /// 
    public partial class Window1 : Window
    {
        System.Windows.Threading.DispatcherTimer timer;

        public Window1()
        {
            InitializeComponent();
            timer = new System.Windows.Threading.DispatcherTimer();
            timer.Interval = new TimeSpan(0, 0, 1);
            timer.Tick += new EventHandler(timer_Tick);
            timer.Start();
        }

        void timer_Tick(object sender, EventArgs e)
        {
            if (GetIdleTick() / 1000 > 10)   
            {
                MessageBox.Show("键盘或鼠标没有操作超过10秒");
            }
        }

        [DllImport("user32.dll")]
        static extern bool GetLastInputInfo(ref LASTINPUTINFO plii);

        public static long GetIdleTick()
        {
            LASTINPUTINFO lastInputInfo = new LASTINPUTINFO();
            lastInputInfo.cbSize = Marshal.SizeOf(lastInputInfo);
            if (!GetLastInputInfo(ref　lastInputInfo)) return 0;
            return Environment.TickCount - (long)lastInputInfo.dwTime;
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct LASTINPUTINFO
        {
            [MarshalAs(UnmanagedType.U4)]
            public int cbSize;
            [MarshalAs(UnmanagedType.U4)]
            public uint dwTime;
        }

    }
}