.net 要获取CPU和内存的使用率，一般是通过 PerformanceCounter 或者 WMI 查询得到，但是如果操作系统经常不正常断电或者别的什么原因，让系统的性能计数器抽风了，可能就会造成初始化 PerformanceCounter 对象出错。
性能计数器错误一般可以通过 lodctr /r 可以修复，但是时不时要这么搞一下，对用户总是太不友好了，所以能通过 Win32API 来获取也是一个不错的选项。
代码已封装到两个工具类 CpuUsageNt 和 MemUsage 里面了
''' <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>
''' </remarks>
Private NotInheritable Class CpuUsageNt
''' <summary>
''' Initializes a new CpuUsageNt instance.
''' </summary>
''' <exception cref="NotSupportedException">One of the system calls fails.</exception>
Public Sub New()
Dim timeInfo(31) As Byte ' SYSTEM_TIME_INFORMATION structure
Dim perfInfo(311) As Byte ' SYSTEM_PERFORMANCE_INFORMATION structure
Dim baseInfo(43) As Byte ' SYSTEM_BASIC_INFORMATION structure
Dim ret As Integer
If (Environment.OSVersion.Platform <> PlatformID.Win32NT) Then
Throw New NotSupportedException()
End If
' get new system time
ret = NtQuerySystemInformation(SYSTEM_TIMEINFORMATION, timeInfo, timeInfo.Length, IntPtr.Zero)
If ret <> NO_ERROR Then
Throw New NotSupportedException()
End If
' get new CPU's idle time
ret = NtQuerySystemInformation(SYSTEM_PERFORMANCEINFORMATION, perfInfo, perfInfo.Length, IntPtr.Zero)
If ret <> NO_ERROR Then
Throw New NotSupportedException()
End If
' get number of processors in the system
ret = NtQuerySystemInformation(SYSTEM_BASICINFORMATION, baseInfo, baseInfo.Length, IntPtr.Zero)
If ret <> NO_ERROR Then
Throw New NotSupportedException()
End If
' 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)
End Sub
''' <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 Function Query() As Integer
Dim timeInfo(31) As Byte ' SYSTEM_TIME_INFORMATION structure
Dim perfInfo(311) As Byte ' SYSTEM_PERFORMANCE_INFORMATION structure
' get new system time
Dim ret As Integer = NtQuerySystemInformation(SYSTEM_TIMEINFORMATION, timeInfo, timeInfo.Length, IntPtr.Zero)
If ret <> NO_ERROR Then
Throw New NotSupportedException()
End If
' get new CPU's idle time
ret = NtQuerySystemInformation(SYSTEM_PERFORMANCEINFORMATION, perfInfo, perfInfo.Length, IntPtr.Zero)
If ret <> NO_ERROR Then
Throw New NotSupportedException()
End If
' CurrentValue = NewValue - OldValue
Dim dbIdleTime As Double = BitConverter.ToInt64(perfInfo, 0) - _oldIdleTime
Dim dbSystemTime As Double = BitConverter.ToInt64(timeInfo, 8) - _oldSystemTime
' CurrentCpuIdle = IdleTime / SystemTime
If dbSystemTime <> 0 Then
dbIdleTime = dbIdleTime / dbSystemTime
End If
' 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 CInt(Fix(dbIdleTime))
End Function
''' <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 Shared Function NtQuerySystemInformation(ByVal dwInfoType As Integer,
ByVal lpStructure() As Byte,
ByVal dwSize As Integer,
ByVal returnLength As IntPtr) As Integer
End Function
''' <summary>Returns the number of processors in the system in a SYSTEM_BASIC_INFORMATION structure.</summary>
Private Const SYSTEM_BASICINFORMATION As Integer = 0
''' <summary>Returns an opaque SYSTEM_PERFORMANCE_INFORMATION structure.</summary>
Private Const SYSTEM_PERFORMANCEINFORMATION As Integer = 2
''' <summary>Returns an opaque SYSTEM_TIMEOFDAY_INFORMATION structure.</summary>
Private Const SYSTEM_TIMEINFORMATION As Integer = 3
''' <summary>The value returned by NtQuerySystemInformation is no error occurred.</summary>
Private Const NO_ERROR As Integer = 0
''' <summary>Holds the old idle time.</summary>
Private _oldIdleTime As Long
''' <summary>Holds the old system time.</summary>
Private _oldSystemTime As Long
''' <summary>Holds the number of processors in the system.</summary>
Private _processorCount As Double
End Class
CpuUsageNt
1 Private NotInheritable Class MemUsage
2 <StructLayout(LayoutKind.Sequential)>
3 Private Structure MEMORY_INFO
4 ''' <summary>
5 ''' 当前结构体大小
6 ''' </summary>
7 Public dwLength As UInteger
8 ''' <summary>
9 ''' 当前内存使用率
10 ''' </summary>
11 Public dwMemoryLoad As UInteger
12 ''' <summary>
13 ''' 总计物理内存大小
14 ''' </summary>
15 Public dwTotalPhys As UInteger
16 ''' <summary>
17 ''' 可用物理内存大小
18 ''' </summary>
19 Public dwAvailPhys As UInteger
20 ''' <summary>
21 ''' 总计交换文件大小
22 ''' </summary>
23 Public dwTotalPageFile As UInteger
24 ''' <summary>
25 ''' 可用交换文件大小
26 ''' </summary>
27 Public dwAvailPageFile As UInteger
28 ''' <summary>
29 ''' 总计虚拟内存大小
30 ''' </summary>
31 Public dwTotalVirtual As UInteger
32 ''' <summary>
33 ''' 可用虚拟内存大小
34 ''' </summary>
35 Public dwAvailVirtual As UInteger
36 End Structure
37 <DllImport("kernel32")>
38 Private Shared Sub GlobalMemoryStatus(ByRef meminfo As MEMORY_INFO)
39 End Sub
40
41 Public Function Query() As Int32
42 Dim iRet As Int32 = 0
43 Try
44 Dim MemInfo As New MEMORY_INFO
45 GlobalMemoryStatus(MemInfo)
46 iRet = CInt(MemInfo.dwMemoryLoad)
47 Debug.Print("[DEBUG] GlobalMemoryStatus dwMemoryLoad={0}", iRet)
48 Catch ex As Exception
49 Debug.Print("[WARN ] GlobalMemoryStatus Err:{0}", ex.Message)
50 End Try
51 Return iRet
52 End Function
53
54 ''' <summary>
55 ''' 格式化容量大小
56 ''' </summary>
57 ''' <param name="size">容量（B）</param>
58 ''' <returns>已格式化的容量</returns>
59 Private Shared Function FormatSize(ByVal size As Double) As String
60 Dim d As Double = size
61 Dim i As Integer = 0
62 Do While (d > 1024) AndAlso (i < 5)
63 d /= 1024
64 i += 1
65 Loop
66 Dim unit() As String = {"B", "KB", "MB", "GB", "TB"}
67 Return (String.Format("{0} {1}", Math.Round(d, 2), unit(i)))
68 End Function
69 End Class
MemUsage
参考资料