大家通过对VB.NET语言的学习，会慢慢的被这款语言强大的功能所吸引住。作为一款完全面向对象的语言，为开发人员带来了很多的好处。比如在处理移动设备方面，就极大的体现了它的作用。在这里我们就先来了解一下VB.NET获取CPU使用率的相关应用技巧。
API声明
- Public Declare Function PdhVbGetOneCounterPath
Lib "PDH.DLL" (ByVal PathString As String,
ByVal PathLength As Integer, ByVal DetailLevel
As Integer, ByVal CaptionString As String)As Integer- Public Declare Function PdhVbCreateCounterPathList
Lib "PDH.DLL" (ByVal PERF_DETAIL As Integer,
ByVal CaptionString As String) As Integer- Public Declare Function PdhVbGetCounterPathFromList
Lib "PDH.DLL" (ByVal Index As Integer, ByVal Buffer
As String, ByVal BufferLength As Integer) As Integer- Public Declare Function PdhOpenQuery Lib "PDH.DLL"
(ByVal Reserved As Integer, ByVal dwUserData As
Integer, ByRef hQuery As Integer) As PDH_STATUS- Public Declare Function PdhCloseQuery Lib "PDH.DLL"
(ByVal hQuery As Integer) As PDH_STATUS- Public Declare Function PdhVbAddCounter Lib "PDH.DLL"
(ByVal QueryHandle As Integer, ByVal CounterPath As
String, ByRef CounterHandle As Integer) As PDH_STATUS- Public Declare Function PdhCollectQueryData Lib
"PDH.DLL" (ByVal QueryHandle As Integer) As PDH_STATUS- Public Declare Function PdhVbIsGoodStatus Lib "PDH.DLL"
(ByVal StatusValue As Integer) As Integer- Public Declare Function PdhVbGetDoubleCounterValue Lib
"PDH.DLL" (ByVal CounterHandle As Integer, ByRef
CounterStatus As Integer) As Double
枚举常数
- Enum PERF_DETAIL
- PERF_DETAIL_NOVICE = 100
- PERF_DETAIL_ADVANCED = 200
- PERF_DETAIL_EXPERT = 300
- PERF_DETAIL_WIZARD = 400
- End Enum
- Enum PDH_STATUS
- PDH_CSTATUS_VALID_DATA = &H0S
- PDH_CSTATUS_NEW_DATA = &H1S
- PDH_CSTATUS_NO_MACHINE = &H800007D0
- PDH_CSTATUS_NO_INSTANCE = &H800007D1
- PDH_MORE_DATA = &H800007D2
- PDH_CSTATUS_ITEM_NOT_VALIDATED = &H800007D3
- PDH_RETRY = &H800007D4
- PDH_NO_DATA = &H800007D5
- PDH_CALC_NEGATIVE_DENOMINATOR = &H800007D6
- PDH_CALC_NEGATIVE_TIMEBASE = &H800007D7
- PDH_CALC_NEGATIVE_VALUE = &H800007D8
- PDH_DIALOG_CANCELLED = &H800007D9
- PDH_CSTATUS_NO_OBJECT = &HC0000BB8
- PDH_CSTATUS_NO_COUNTER = &HC0000BB9
- PDH_CSTATUS_INVALID_DATA = &HC0000BBA
- PDH_MEMORY_ALLOCATION_FAILURE = &HC0000BBB
- PDH_INVALID_HANDLE = &HC0000BBC
- PDH_INVALID_ARGUMENT = &HC0000BBD
- PDH_FUNCTION_NOT_FOUND = &HC0000BBE
- PDH_CSTATUS_NO_COUNTERNAME = &HC0000BBF
- PDH_CSTATUS_BAD_COUNTERNAME = &HC0000BC0
- PDH_INVALID_BUFFER = &HC0000BC1
- PDH_INSUFFICIENT_BUFFER = &HC0000BC2
- PDH_CANNOT_CONNECT_MACHINE = &HC0000BC3
- PDH_INVALID_PATH = &HC0000BC4
- PDH_INVALID_INSTANCE = &HC0000BC5
- PDH_INVALID_DATA = &HC0000BC6
- PDH_NO_DIALOG_DATA = &HC0000BC7
- PDH_CANNOT_READ_NAME_STRINGS = &HC0000BC8
- End Enum
- Public Const ERROR_SUCCESS As Short = 0
- Public Structure CounterInfo
- Dim hCounter As Integer
- Dim strName As String
- End Structure
在窗体的load事件里面添加一下语句:
- Dim pdhStatus As PDH_STATUS
- pdhStatus = PdhOpenQuery
(0, 1, hQuery)- If pdhStatus <>
ERROR_SUCCESS Then- MsgBox("OpenQuery failed")
- End
- End If
在窗体的closed事件里面添加以下代码
- PdhCloseQuery(hQuery)
VB.NET获取CPU使用率之显示利用率信息
- Private Sub UpdateValues()
- Dim dblCounterValue As Double
- Dim pdhStatus As Integer
- Dim strInfo As String
- Dim i As Integer
- PdhCollectQueryData(hQuery)
- i = 0
- dblCounterValue =
PdhVbGetDoubleCounterValue
(Counters(i).hCounter, pdhStatus)
将VB.NET获取CPU使用率显示在标签中
- If (pdhStatus = PDH_STATUS.
PDH_CSTATUS_VALID_DATA) or
(pdhStatus = PDH_STATUS.PDH_
CSTATUS_NEW_DATA) Then- strInfo = "CPU 使用率： " &
VB6.Format(dblCounterValue, "0.00")- pb1.Value = dblCounterValue
- Me.Text = VB6.Format(dblCounterValue,
"0") & "% - CPU 当前状态"- End If
- Label1.Text = strInfo
- End Sub
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