C# 几种获取电脑内存、CPU信息的方案

计数器、WMI

获取设备的内存信息，如系统可用运行内存：

 1     public static async Task<double> GetMemoryAvailableAsync(FileSizeUnit fileSizeUnit = FileSizeUnit.GB)

 2     {

 3         return await Task.Run(() =>

 4         {

 5             using var managementClass = new ManagementClass("Win32_PerfFormattedData_PerfOS_Memory");

 6             using var instances = managementClass.GetInstances();

 7             double available = 0;

 8             foreach (var mo in instances)

 9             {

10                 //AvailableMBytes单位是MB

11                 var size = long.Parse(mo.Properties["AvailableMBytes"].Value.ToString()) * 1024 * 1024;

12                 available += size.ConvertTo(fileSizeUnit);

13             }

14

15             return available;

16         });

17     }

以上是ManagementClass方式实现，还有ManagementObjectSearcher，都是WMI检索查询。

WMI查询比较慢，上面一段耗时在200ms+。

还有一种用的较多的，PerformanceCounter性能计数器，以CPU获取为例：

 1     public static async Task<double> GetUsageByCounterAsync()

 2     {

 3         //CPU计数器

 4         using var pcCpuUsage = new PerformanceCounter("Processor", "% Processor Time", "_Total") { MachineName = "." };

 5         // NextValue首次会返回0，所以需要加个延时下次再获取值

 6         pcCpuUsage.NextValue();

 7         await Task.Delay(TimeSpan.FromMilliseconds(500));

 8         var cpuUsed = pcCpuUsage.NextValue();

 9         return cpuUsed;

10     }

性能计数器，也有一定的耗时40ms以上。另外因为它实现方式，初始化后无法第一次获取到真正数值，需要间隔一段时间再去拿。所以此方案实际耗时挺高

WMI、性能计数器，昨天遇到了使用异常：

看源码，计数器是注册表PerformanceData位置损坏了，而Management是IWbemServices获取状态码ErrorCode异常。

PerformanceCounter是WMI，而WMI是基于WBEM协议实现的，所以我理解成上面的异常其实是一类问题。

官网有对此类异常有一些描述：重新生成性能计数器库值 - Windows Server | Microsoft Learn

所以基于PerformanceCounter、ManagementClass以及ManagementObjectSearcher的实现，有一定风险。

kernel32

kernel32下有个函数可以获取内存状态

1     [DllImport("kernel32.dll")]

2     [return: MarshalAs(UnmanagedType.Bool)]

3     static extern bool GlobalMemoryStatusEx(ref MEMORYINFO mi);

以下是获取可用运行内存的实现：

    //Define the information structure of memory

    [StructLayout(LayoutKind.Sequential)]

    struct MEMORYINFO

    {

        public uint dwLength; //Current structure size

        public uint dwMemoryLoad; //Current memory utilization

        public ulong ullTotalPhys; //Total physical memory size

        public ulong ullAvailPhys; //Available physical memory size

        public ulong ullTotalPageFile; //Total Exchange File Size

        public ulong ullAvailPageFile; //Total Exchange File Size

        public ulong ullTotalVirtual; //Total virtual memory size

        public ulong ullAvailVirtual; //Available virtual memory size

        public ulong ullAvailExtendedVirtual; //Keep this value always zero

    }

    /// <summary>

    /// Get the current memory usage

    /// </summary>

    /// <returns></returns>

    private static MEMORYINFO GetMemoryStatus()

    {

        MEMORYINFO memoryInfo = new MEMORYINFO();

        memoryInfo.dwLength = (uint)System.Runtime.InteropServices.Marshal.SizeOf(memoryInfo);

        GlobalMemoryStatusEx(ref memoryInfo);

        return memoryInfo;

    }

    /// <summary>

    /// 获取系统可用运行内存

    /// </summary>

    /// <param name="fileSizeUnit">默认单位GB</param>

    /// <returns></returns>

    public static double GetMemoryAvailable(FileSizeUnit fileSizeUnit = FileSizeUnit.GB)

    {

        var memoryStatus = GetMemoryStatus();

        var memoryAvailable = ((long)memoryStatus.ullAvailPhys).ConvertTo(fileSizeUnit);

        return memoryAvailable;

    }

上述方式，获取速度超快，几乎不耗时。

通过Kernel32-GetSystemTimes方式，获取CPU信息（CPU比例计算逻辑，代码略多点）：

 1     /// <summary>

 2     /// 获取CPU占用率/使用率（单位：%）

 3     /// </summary>

 4     /// <returns></returns>

 5     public static async Task<double> GetUsageByKernelAsync()

 6     {

 7         long idleTime1 = 0;

 8         long kernelTime1 = 0;

 9         long userTime1 = 0;

10         if (GetSystemTimes(out var lpIdleTime, out var lpKernelTime, out var lpUserTime))

11         {

12             idleTime1 = lpIdleTime;

13             kernelTime1 = lpKernelTime;

14             userTime1 = lpUserTime;

15         }

16         //添加俩次获取CPU信息的间隔

17         await Task.Delay(TimeSpan.FromSeconds(0.5));

18         long idleTime2 = 0;

19         long kernelTime2 = 0;

20         long userTime2 = 0;

21         if (GetSystemTimes(out var lpIdleTime2, out var lpKernelTime2, out var lpUserTime2))

22         {

23             idleTime2 = lpIdleTime2;

24             kernelTime2 = lpKernelTime2;

25             userTime2 = lpUserTime2;

26         }

27         //分别获取到用户时间、内核时间、空闲时间

28         var userTime = userTime2 - userTime1;

29         var kernelTime = kernelTime2 - kernelTime1;

30         var idleTime = idleTime2 - idleTime1;

31         //计算Cpu占用率。计算公式：用户时间+内核时间-空闲时间/用户时间+内核时间

32         var systemTotal = kernelTime + userTime;

33         var cpu = (systemTotal - idleTime) * 10000 / systemTotal;

34         return cpu / 100.0;

35     }

36

37     /// <summary>

38     /// 获取系统CPU时间数据

39     /// </summary>

40     /// <param name="lpIdleTime">空闲时间</param>

41     /// <param name="lpKernelTime">内核时间</param>

42     /// <param name="lpUserTime">用户时间</param>

43     /// <returns></returns>

44     [DllImport("kernel32.dll", SetLastError = true)]

45     static extern bool GetSystemTimes(out long lpIdleTime, out long lpKernelTime, out long lpUserTime);

另外，也有一种途径可以获取到内存信息，引用程序集Microsoft.VisualBasic，Microsoft.VisualBasic.Devices下有个ComputerInfo类

var physicalMemory = new Microsoft.VisualBasic.Devices.ComputerInfo().AvailablePhysicalMemory;

可以拿到可用内存、总内存，不过CPU信息是没有的。

ComputerInfo的内部源码，我标注了下：

所以ComputerInfo，也是基于GlobalMemoryStatusEx函数做了封装，大家可以直接用。

关键字：【Kernek32-GlobalMemoryStatusEx】【Kernek32-GetSystemTimes】

参考列表：

How to get system specs (processor, memory etc...) in C#? (microsoft.com)
Get the CPU Usage in C# | Delft Stack
C#获取CPU和内存使用率 - 雨水的命运 - 博客园 (cnblogs.com)
Determine CPU usage of current process (C++ and C#) | Philosophical Geek
Get CPU Usage with GetSystemTimes - CodeProject

C# 几种获取电脑内存、CPU信息的方案的相关教程结束。