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
{
     ///   <summary>
     ///  Window1.xaml 的交互逻辑
     ///   </summary>
     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;
        }

    }
}