c#超时锁定

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;

namespace VistaRenderer
{
    public partial class FrmTestTimeout : Form
    {
        public FrmTestTimeout()
        {
            InitializeComponent();// this.timer1 = new System.Windows.Forms.Timer(this.components);
        }

        private void FrmTestTimeout_Load(object sender, EventArgs e)
        {
            timer1.Enabled = true;
            timer1.Interval = 2 * 1000;// 计时器触发间隔 2秒
            this.timer1.Tick += new EventHandler(timer1_Tick);
        }
        /// <summary>
        /// 计时器触发
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void timer1_Tick(object sender, EventArgs e)
        {
            // 距离上一次系统输入时间大于5秒
            if (GetLastInputTime() >=  5 * 1000)
            {
                MessageBox.Show("time out");//这里可以写超时处理，比如弹出一个锁定窗口
            }
        }

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

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

        /// <summary>
        /// 获得距离上一次操作时间间隔
        /// </summary>
        /// <returns></returns>
        static long GetLastInputTime()
        {
            LASTINPUTINFO vLastInputInfo = new LASTINPUTINFO();
            vLastInputInfo.cbSize = Marshal.SizeOf(vLastInputInfo);
            if (!GetLastInputInfo(ref vLastInputInfo)) return 0;
            return Environment.TickCount - (long)vLastInputInfo.dwTime;
        }

    }
}