.NET获取CPU使用率

获得Cpu使用率,首先写一个类,如下:


 

using System;
using Microsoft.Win32;
using System.Diagnostics;
using System.Runtime.InteropServices;

namespace CpuUsage
{
/// <summary>
/// SysInfo 的摘要说明。
/// </summary>
public class SystemInfo
{
#region CpuUsage类
/// <summary>
/// Defines an abstract base class for implementations of CPU usage counters.
/// </summary>
public abstract class CpuUsage
{
/// <summary>
/// Creates and returns a CpuUsage instance that can be used to query the CPU time on this operating system.
/// </summary>
/// <returns>An instance of the CpuUsage class.</returns>
/// <exception cref="NotSupportedException">This platform is not supported -or- initialization of the CPUUsage object failed.</exception>
public static CpuUsage Create()
{
if (m_CpuUsage == null)
{
if (Environment.OSVersion.Platform == PlatformID.Win32NT)
m_CpuUsage = new CpuUsageNt();
else if (Environment.OSVersion.Platform == PlatformID.Win32Windows)
m_CpuUsage = new CpuUsage9x();
else
throw new NotSupportedException();
}
return m_CpuUsage;
}
/// <summary>
/// Determines the current average CPU load.
/// </summary>
/// <returns>An integer that holds the CPU load percentage.</returns>
/// <exception cref="NotSupportedException">One of the system calls fails. The CPU time can not be obtained.</exception>
public abstract int Query();
/// <summary>
/// Holds an instance of the CPUUsage class.
/// </summary>
private static CpuUsage m_CpuUsage = null;
}

//------------------------------------------- win 9x ---------------------------------------

/// <summary>
/// Inherits the CPUUsage class and implements the Query method for Windows 9x systems.
/// </summary>
/// <remarks>
/// <p>This class works on Windows 98 and Windows Millenium Edition.</p>
/// <p>You should not use this class directly in your code. Use the CPUUsage.Create() method to instantiate a CPUUsage object.</p>
/// </remarks>
internal sealed class CpuUsage9x : CpuUsage
{
/// <summary>
/// Initializes a new CPUUsage9x instance.
/// </summary>
/// <exception cref="NotSupportedException">One of the system calls fails.</exception>
public CpuUsage9x()
{
try
{
// start the counter by reading the value of the 'StartStat' key
RegistryKey startKey = Registry.DynData.OpenSubKey(@"PerfStats\StartStat", false);
if (startKey == null)
throw new NotSupportedException();
startKey.GetValue(@"KERNEL\CPUUsage");
startKey.Close();
// open the counter's value key
m_StatData = Registry.DynData.OpenSubKey(@"PerfStats\StatData", false);
if (m_StatData == null)
throw new NotSupportedException();
}
catch (NotSupportedException e)
{
throw e;
}
catch (Exception e)
{
throw new NotSupportedException("Error while querying the system information.", e);
}
}
/// <summary>
/// Determines the current average CPU load.
/// </summary>
/// <returns>An integer that holds the CPU load percentage.</returns>
/// <exception cref="NotSupportedException">One of the system calls fails. The CPU time can not be obtained.</exception>
public override int Query()
{
try
{
return (int)m_StatData.GetValue(@"KERNEL\CPUUsage");
}
catch (Exception e)
{
throw new NotSupportedException("Error while querying the system information.", e);
}
}
/// <summary>
/// Closes the allocated resources.
/// </summary>
~CpuUsage9x()
{
try
{
m_StatData.Close();
}
catch { }
// stopping the counter
try
{
RegistryKey stopKey = Registry.DynData.OpenSubKey(@"PerfStats\StopStat", false);
stopKey.GetValue(@"KERNEL\CPUUsage", false);
stopKey.Close();
}
catch { }
}
/// <summary>Holds the registry key that's used to read the CPU load.</summary>
private RegistryKey m_StatData;
}

//------------------------------------------- win nt ---------------------------------------

/// <summary>
/// Inherits the CPUUsage class and implements the Query method for Windows NT systems.
/// </summary>
/// <remarks>
/// <p>This class works on Windows NT4, Windows 2000, Windows XP, Windows .NET Server and higher.</p>
/// <p>You should not use this class directly in your code. Use the CPUUsage.Create() method to instantiate a CPUUsage object.</p>
/// </remarks>
internal sealed class CpuUsageNt : CpuUsage
{
/// <summary>
/// Initializes a new CpuUsageNt instance.
/// </summary>
/// <exception cref="NotSupportedException">One of the system calls fails.</exception>
public CpuUsageNt()
{
byte[] timeInfo = new byte[32]; // SYSTEM_TIME_INFORMATION structure
byte[] perfInfo = new byte[312]; // SYSTEM_PERFORMANCE_INFORMATION structure
byte[] baseInfo = new byte[44]; // SYSTEM_BASIC_INFORMATION structure
int ret;
// get new system time
ret = NtQuerySystemInformation(SYSTEM_TIMEINFORMATION, timeInfo, timeInfo.Length, IntPtr.Zero);
if (ret != NO_ERROR)
throw new NotSupportedException();
// get new CPU's idle time
ret = NtQuerySystemInformation(SYSTEM_PERFORMANCEINFORMATION, perfInfo, perfInfo.Length, IntPtr.Zero);
if (ret != NO_ERROR)
throw new NotSupportedException();
// get number of processors in the system
ret = NtQuerySystemInformation(SYSTEM_BASICINFORMATION, baseInfo, baseInfo.Length, IntPtr.Zero);
if (ret != NO_ERROR)
throw new NotSupportedException();
// store new CPU's idle and system time and number of processors
oldIdleTime = BitConverter.ToInt64(perfInfo, 0); // SYSTEM_PERFORMANCE_INFORMATION.liIdleTime
oldSystemTime = BitConverter.ToInt64(timeInfo, 8); // SYSTEM_TIME_INFORMATION.liKeSystemTime
processorCount = baseInfo[40];
}
/// <summary>
/// Determines the current average CPU load.
/// </summary>
/// <returns>An integer that holds the CPU load percentage.</returns>
/// <exception cref="NotSupportedException">One of the system calls fails. The CPU time can not be obtained.</exception>
public override int Query()
{
byte[] timeInfo = new byte[32]; // SYSTEM_TIME_INFORMATION structure
byte[] perfInfo = new byte[312]; // SYSTEM_PERFORMANCE_INFORMATION structure
double dbIdleTime, dbSystemTime;
int ret;
// get new system time
ret = NtQuerySystemInformation(SYSTEM_TIMEINFORMATION, timeInfo, timeInfo.Length, IntPtr.Zero);
if (ret != NO_ERROR)
throw new NotSupportedException();
// get new CPU's idle time
ret = NtQuerySystemInformation(SYSTEM_PERFORMANCEINFORMATION, perfInfo, perfInfo.Length, IntPtr.Zero);
if (ret != NO_ERROR)
throw new NotSupportedException();
// CurrentValue = NewValue - OldValue
dbIdleTime = BitConverter.ToInt64(perfInfo, 0) - oldIdleTime;
dbSystemTime = BitConverter.ToInt64(timeInfo, 8) - oldSystemTime;
// CurrentCpuIdle = IdleTime / SystemTime
if (dbSystemTime != 0)
dbIdleTime = dbIdleTime / dbSystemTime;
// CurrentCpuUsage% = 100 - (CurrentCpuIdle * 100) / NumberOfProcessors
dbIdleTime = 100.0 - dbIdleTime * 100.0 / processorCount + 0.5;
// store new CPU's idle and system time
oldIdleTime = BitConverter.ToInt64(perfInfo, 0); // SYSTEM_PERFORMANCE_INFORMATION.liIdleTime
oldSystemTime = BitConverter.ToInt64(timeInfo, 8); // SYSTEM_TIME_INFORMATION.liKeSystemTime
return (int)dbIdleTime;
}
/// <summary>
/// NtQuerySystemInformation is an internal Windows function that retrieves various kinds of system information.
/// </summary>
/// <param name="dwInfoType">One of the values enumerated in SYSTEM_INFORMATION_CLASS, indicating the kind of system information to be retrieved.</param>
/// <param name="lpStructure">Points to a buffer where the requested information is to be returned. The size and structure of this information varies depending on the value of the SystemInformationClass parameter.</param>
/// <param name="dwSize">Length of the buffer pointed to by the SystemInformation parameter.</param>
/// <param name="returnLength">Optional pointer to a location where the function writes the actual size of the information requested.</param>
/// <returns>Returns a success NTSTATUS if successful, and an NTSTATUS error code otherwise.</returns>
[DllImport("ntdll", EntryPoint = "NtQuerySystemInformation")]
private static extern int NtQuerySystemInformation(int dwInfoType, byte[] lpStructure, int dwSize, IntPtr returnLength);
/// <summary>Returns the number of processors in the system in a SYSTEM_BASIC_INFORMATION structure.</summary>
private const int SYSTEM_BASICINFORMATION = 0;
/// <summary>Returns an opaque SYSTEM_PERFORMANCE_INFORMATION structure.</summary>
private const int SYSTEM_PERFORMANCEINFORMATION = 2;
/// <summary>Returns an opaque SYSTEM_TIMEOFDAY_INFORMATION structure.</summary>
private const int SYSTEM_TIMEINFORMATION = 3;
/// <summary>The value returned by NtQuerySystemInformation is no error occurred.</summary>
private const int NO_ERROR = 0;
/// <summary>Holds the old idle time.</summary>
private long oldIdleTime;
/// <summary>Holds the old system time.</summary>
private long oldSystemTime;
/// <summary>Holds the number of processors in the system.</summary>
private double processorCount;
}
#endregion

/// <summary>
/// 获得Cpu使用率
/// </summary>
/// <returns>返回使用率</returns>
public static int GetCpuUsage()
{
return CpuUsage.Create().Query();
}
}
}

使用方法如下:

新建一个webform,拖入一个Timer控件(Timer1),拖入一个Lable控件(Lable1),时钟周期设为:1000毫秒,然后双击Timer控件,在时钟事件中写:

Lable1.Text=SystemInfo.GetCpuUsage()

即可看到CPU使用率

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posted @ 2012-02-09 11:25  开发者精选资讯  阅读(836)  评论(1编辑  收藏  举报