使用 C# 检索系统正常运行时间

Question

有没有使用 C# 获得系统正常运行时间的简单方法？

Answer 1

public TimeSpan UpTime {
    get {
        using (var uptime = new PerformanceCounter("System", "System Up Time")) {
            uptime.NextValue();       //Call this an extra time before reading its value
            return TimeSpan.FromSeconds(uptime.NextValue());
        }
    }
}

Answer 2

我有点晚了，但另一个简单的方法是使用GetTickCount64 函数，该函数从Windows Vista 开始可用，并且不会像GetTickCount 那样溢出：

public static TimeSpan GetUpTime()
{
    return TimeSpan.FromMilliseconds(GetTickCount64());
}

[DllImport("kernel32")]
extern static UInt64 GetTickCount64();

Answer 3

System.Environment.TickCount 获取系统重启后的毫秒数。

注意它是一个 Int32 并且会在 24.9 天后溢出并变为负数。请参阅 MDSN 文档上的备注。

Answer 4

根据任务管理器，我的机器的正常运行时间为58 days 17 hours。我在这里尝试了每个答案，快速的答案稍微偏离了一点（大约 1-3 分钟，但正常运行时间超过 58 天）：

Stopwatch.GetTimeStamp():                   58days 17hours 11minutes 25seconds
~Time to calculate (ms): 6.8413
DllImport GetTickCount64():                 58days 17hours 13minutes 34seconds
~Time to calculate (ms): 0.2192
PerformanceCounter(System, System Up Time): 58days 17hours 14minutes 02seconds
~Time to calculate (ms): 1233.2854
ManagementObject LastBootUpTime:            58days 17hours 14minutes 02seconds
~Time to calculate (ms): 30.0283

最后两个，使用 PerformanceCounter 或使用 ManagementObject，总是与 Windows 任务管理器在同一秒内（只需要相信我的话，或者使用下面的代码自己尝试）。根据结果​​，我将使用ManagementObject LastBootUpTime 方法，因为它比PerformanceCounter 快得多，但与任务管理器相比仍然非常准确。

请注意，在打印时间之前，我确实从每个方法中减去了当前经过的时间，但整个过程的运行时间不到 2 秒，因此无论如何不能通过不正确地考虑执行时间来解释时间偏移。这是我使用的代码：

[System.Runtime.InteropServices.DllImport("kernel32")]
extern static UInt64 GetTickCount64();

public static void Main()
{
    var start = Stopwatch.StartNew();

    var eachStart = Stopwatch.StartNew();
    var ticks = Stopwatch.GetTimestamp();
    var uptime = ((double)ticks) / Stopwatch.Frequency;
    var uptimeTimeSpan = TimeSpan.FromSeconds(uptime);
    Console.WriteLine("Stopwatch.GetTimeStamp():                   " + uptimeTimeSpan.Subtract(start.Elapsed).ToString(@"dd\d\a\y\s\ hh\h\o\u\r\s\ mm\m\i\n\u\t\e\s\ ss\s\e\c\o\n\d\s"));
    Console.WriteLine($"~Time to calculate (ms): {eachStart.Elapsed.TotalMilliseconds}");

    eachStart.Restart();
    Console.WriteLine("DllImport GetTickCount64():                 " + TimeSpan.FromMilliseconds(GetTickCount64()).Subtract(start.Elapsed).ToString(@"dd\d\a\y\s\ hh\h\o\u\r\s\ mm\m\i\n\u\t\e\s\ ss\s\e\c\o\n\d\s"));
    Console.WriteLine($"~Time to calculate (ms): {eachStart.Elapsed.TotalMilliseconds}");

    eachStart.Restart();
    var upTime = new PerformanceCounter("System", "System Up Time");
    upTime.NextValue();       //Call this an extra time before reading its value
    Console.WriteLine("PerformanceCounter(System, System Up Time): " + TimeSpan.FromSeconds(upTime.NextValue()).Subtract(start.Elapsed).ToString(@"dd\d\a\y\s\ hh\h\o\u\r\s\ mm\m\i\n\u\t\e\s\ ss\s\e\c\o\n\d\s"));
    Console.WriteLine($"~Time to calculate (ms): {eachStart.Elapsed.TotalMilliseconds}");

    eachStart.Restart();
    ManagementObject mo = new ManagementObject(@"\\.\root\cimv2:Win32_OperatingSystem=@");
    DateTime lastBootUp = ManagementDateTimeConverter.ToDateTime(mo["LastBootUpTime"].ToString());
    Console.WriteLine("ManagementObject LastBootUpTime:            " + (DateTime.Now.ToUniversalTime() - lastBootUp.ToUniversalTime()).Subtract(start.Elapsed).ToString(@"dd\d\a\y\s\ hh\h\o\u\r\s\ mm\m\i\n\u\t\e\s\ ss\s\e\c\o\n\d\s"));
    Console.WriteLine($"~Time to calculate (ms): {eachStart.Elapsed.TotalMilliseconds}");
}

Answer 5

精确且大于System.Environment.TickCount，不涉及操作系统可怕的性能计数器、WMI 或本机调用：

var ticks = Stopwatch.GetTimestamp();
var uptime = ((double)ticks) / Stopwatch.Frequency;
var uptimeSpan = TimeSpan.FromSeconds(uptime);

Answer 6

最简单和正确的方法是

public static TimeSpan GetUptime()
{
    ManagementObject mo = new ManagementObject(@"\\.\root\cimv2:Win32_OperatingSystem=@");
    DateTime lastBootUp = ManagementDateTimeConverter.ToDateTime(mo["LastBootUpTime"].ToString());
    return DateTime.Now.ToUniversalTime() - lastBootUp.ToUniversalTime();
}

Answer 7

简单，但可以做到：

    static DateTime getLastBootTime(ManagementObject mObject)
    {
        PropertyData pd = mObject.Properties["LastBootUpTime"];
        string name = pd.Name.ToString();
        DateTime lastBoot = parseCmiDateTime(pd.Value.ToString());
        return lastBoot;
    }

    static ManagementObject getServerOSObject(string serverName)
    {
        ManagementObjectSearcher mSearcher = new ManagementObjectSearcher("Select * From Win32_OperatingSystem");
        mSearcher.Scope = new ManagementScope(String.Format(@"\\{0}\root\cimv2", serverName));
        ManagementObjectCollection mObjects = mSearcher.Get();
        if (mObjects.Count != 1) throw new Exception(String.Format("Expected 1 object, returned {0}.", mObjects.Count));
        foreach (ManagementObject m in mObjects)
        {
            //No indexing on collection
            return m;
        }
        throw new Exception("Something went wrong!");
    }

Answer 8

如果您使用的是更高版本的 .NET（Core 3.0/.NET 5.0 或更高版本），那么 Environment 类现在有一个 TickCount64 property。

这不会受到 TickCount 属性的环绕问题的影响，您也不必求助于 P/Invoke 来获取值。

long tickCountMs = Environment.TickCount64;
var uptime = TimeSpan.FromMilliseconds(tickCountMs);

Answer 9

我知道问题既老又解决，但我能想到的最简单的解决方案就是使用 Enviroment.TickCount 属性，它返回自系统启动以来的毫秒数：

System.DateTime SystemStartTime = DateAndTime.Now.AddMilliseconds(-Environment.TickCount);
System.DateTime Uptime = DateAndTime.Now - SystemStartTime;

这个解决方案比公认的答案快很多。

Answer 10

目前为止（唯一的）正确答案：

使用 32 位定时器非常危险，除了有限的使用外，其他人都容易出错。

我不确定 NativeMethods 类的东西何时被添加到 .net，但确实如此。您肯定希望避免 P/Invoke 开销。这样做：

using System;
using System.Runtime.InteropServices;

namespace Mu
{

    // prevents PInvoke (not in NativeMethods class) or Stack walk (NativeMethods class) performance penalties.
    internal static partial class SafeNativeMethods
    {
        [DllImport("kernel32")]
        internal extern static UInt64 GetTickCount64();

    }
    public static class MuTime
    {
        public static UInt64 UpTimeMillis {  get { return SafeNativeMethods.GetTickCount64();  } }
    }
}

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