系统空闲时间 解决 GetLastInputInfo 负数问题

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;

namespace ATMDefendCabinEventVideoForm
{
public class CheckComputerFreeState
{

/// <summary>
/// 创建结构体用于返回捕获时间
/// </summary>
[StructLayout(LayoutKind.Sequential)]
struct LASTINPUTINFO
{
/// <summary>
/// 设置结构体块容量
/// </summary>
[MarshalAs(UnmanagedType.U4)]
public int cbSize;

/// <summary>
/// 抓获的时间
/// </summary>
[MarshalAs(UnmanagedType.U4)]
public uint dwTime;
}

[DllImport("user32.dll")]
private static extern bool GetLastInputInfo(ref LASTINPUTINFO plii);
/// <summary>
/// 获取键盘和鼠标没有操作的时间
/// </summary>
/// <returns>用户上次使用系统到现在的时间间隔，单位为秒</returns>
public static long GetLastInputTime()
{
LASTINPUTINFO vLastInputInfo = new LASTINPUTINFO();
vLastInputInfo.cbSize = Marshal.SizeOf(vLastInputInfo);
if (!GetLastInputInfo(ref vLastInputInfo))
{
return 0;
}
else
{
Console.WriteLine("TickCount=" + Environment.TickCount);
Console.WriteLine("vLastInputInfo.dwTime=" + vLastInputInfo.dwTime);
Console.WriteLine("vLastInputInfo.dwTime & Int32.MaxValue=" + (vLastInputInfo.dwTime & Int32.MaxValue));
var count = Environment.TickCount & Int32.MaxValue - (long)(vLastInputInfo.dwTime & Int32.MaxValue);
var icount = count / 1000;
return icount;
}
}

public static long GetLastInputTimeMinute()
{
LASTINPUTINFO vLastInputInfo = new LASTINPUTINFO();
vLastInputInfo.cbSize = Marshal.SizeOf(vLastInputInfo);
if (!GetLastInputInfo(ref vLastInputInfo))
{
return 0;
}
else
{
var count = Environment.TickCount - (long)vLastInputInfo.dwTime;
var icount = count / (1000*60);
return icount;
}
}

}
}