PerformanceCounter.NextValue PerformanceCounter.NextValue PerformanceCounter.NextValue PerformanceCounter.NextValue Method

정의

카운터 샘플을 가져와 계산된 값을 반환합니다.Obtains a counter sample and returns the calculated value for it.

public:
 float NextValue();
public float NextValue ();
member this.NextValue : unit -> single
Public Function NextValue () As Single

반환

이 카운터에 대해 시스템이 다음에 가져오는 계산된 값입니다.The next calculated value that the system obtains for this counter.

예외

인스턴스가 성능 카운터와 제대로 연결되어 있지 않은 경우The instance is not correctly associated with a performance counter.

시스템 API에 액세스할 때 오류가 발생했습니다.An error occurred when accessing a system API.

관리자 권한 없이 실행되는 코드가 성능 카운터를 읽으려고 한 경우Code that is executing without administrative privileges attempted to read a performance counter.

예제

다음 코드 예제는 ElapsedTime 사용 하 여 카운터를 NextValue 기간 동안 카운터의 값을 표시 하는 방법.The following code example creates an ElapsedTime counter and uses the NextValue method to display the counter's values over a time period.

#using <System.dll>

using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;
using namespace System::Diagnostics;
using namespace System::Runtime::InteropServices;

void OutputSample( CounterSample s )
{
   Console::WriteLine( "\r\n+++++++++++" );
   Console::WriteLine( "Sample values - \r\n" );
   Console::WriteLine( "   BaseValue        = {0}", s.BaseValue );
   Console::WriteLine( "   CounterFrequency = {0}", s.CounterFrequency );
   Console::WriteLine( "   CounterTimeStamp = {0}", s.CounterTimeStamp );
   Console::WriteLine( "   CounterType      = {0}", s.CounterType );
   Console::WriteLine( "   RawValue         = {0}", s.RawValue );
   Console::WriteLine( "   SystemFrequency  = {0}", s.SystemFrequency );
   Console::WriteLine( "   TimeStamp        = {0}", s.TimeStamp );
   Console::WriteLine( "   TimeStamp100nSec = {0}", s.TimeStamp100nSec );
   Console::WriteLine( "++++++++++++++++++++++" );
}

void CollectSamples()
{
   String^ categoryName = "ElapsedTimeSampleCategory";
   String^ counterName = "ElapsedTimeSample";
   
   // Create the performance counter category.
   if (  !PerformanceCounterCategory::Exists( categoryName ) )
   {
      CounterCreationDataCollection^ CCDC = gcnew CounterCreationDataCollection;
      
      // Add the counter.
      CounterCreationData^ ETimeData = gcnew CounterCreationData;
      ETimeData->CounterType = PerformanceCounterType::ElapsedTime;
      ETimeData->CounterName = counterName;
      CCDC->Add( ETimeData );
      
      // Create the category.
      PerformanceCounterCategory::Create( categoryName,
         "Demonstrates ElapsedTime performance counter usage.",
         CCDC );
   }
   else
   {
      Console::WriteLine( "Category exists - {0}", categoryName );
   }

   
   // Create the performance counter.
   PerformanceCounter^ PC = gcnew PerformanceCounter( categoryName,
                                                      counterName,
                                                      false );
   // Initialize the counter.
   PC->RawValue = Stopwatch::GetTimestamp();

   DateTime Start = DateTime::Now;
   
   // Loop for the samples.
   for ( int j = 0; j < 100; j++ )
   {
      // Output the values.
      if ( (j % 10) == 9 )
      {
         Console::WriteLine( "NextValue() = {0}", PC->NextValue() );
         Console::WriteLine( "Actual elapsed time = {0}", DateTime::Now.Subtract( Start ) );
         OutputSample( PC->NextSample() );
      }
      
      // Reset the counter on every 20th iteration.
      if ( j % 20 == 0 )
      {
         PC->RawValue = Stopwatch::GetTimestamp();
         Start = DateTime::Now;
      }
      System::Threading::Thread::Sleep( 50 );
   }

   Console::WriteLine( "Elapsed time = {0}", DateTime::Now.Subtract( Start ) );
}

int main()
{
   CollectSamples();
}

using System;
using System.Collections;
using System.Collections.Specialized;
using System.Diagnostics;
using System.Runtime.InteropServices;

public class App 
{

    public static void Main()
    {	
        CollectSamples();
    }

   
    public static void CollectSamples()
    {
        const String categoryName = "ElapsedTimeSampleCategory";
        const String counterName = "ElapsedTimeSample";

        // If the category does not exist, create the category and exit.
        // Performance counters should not be created and immediately used.
        // There is a latency time to enable the counters, they should be created
        // prior to executing the application that uses the counters.
        // Execute this sample a second time to use the category.
        if ( !PerformanceCounterCategory.Exists(categoryName) ) 
        {

            CounterCreationDataCollection CCDC = new CounterCreationDataCollection();

            // Add the counter.
            CounterCreationData ETimeData = new CounterCreationData();
            ETimeData.CounterType = PerformanceCounterType.ElapsedTime;
            ETimeData.CounterName = counterName;
            CCDC.Add(ETimeData);	   
		
            // Create the category.
            PerformanceCounterCategory.Create(categoryName,
                    "Demonstrates ElapsedTime performance counter usage.",
                PerformanceCounterCategoryType.SingleInstance, CCDC);
            // Return, rerun the application to make use of the new counters.
            return;

        }
        else
        {
            Console.WriteLine("Category exists - {0}", categoryName);
        }        

        // Create the performance counter.
        PerformanceCounter PC = new PerformanceCounter(categoryName, 
                                                       counterName, 
                                                       false);
        // Initialize the counter.
        PC.RawValue = Stopwatch.GetTimestamp();

        DateTime Start = DateTime.Now;

        // Loop for the samples.
        for (int j = 0; j < 100; j++) 
        {
            // Output the values.
            if ((j % 10) == 9) 
            {
                Console.WriteLine("NextValue() = " + PC.NextValue().ToString());
                Console.WriteLine("Actual elapsed time = " + DateTime.Now.Subtract(Start).ToString());
                OutputSample(PC.NextSample());
            }

            // Reset the counter on every 20th iteration.
            if (j % 20 == 0)
            {
                PC.RawValue = Stopwatch.GetTimestamp();
                Start = DateTime.Now;
            }
            System.Threading.Thread.Sleep(50);
        }

        Console.WriteLine("Elapsed time = " + DateTime.Now.Subtract(Start).ToString());
    }

	
    private static void OutputSample(CounterSample s)
    {
        Console.WriteLine("\r\n+++++++++++");
        Console.WriteLine("Sample values - \r\n");
        Console.WriteLine("   BaseValue        = " + s.BaseValue);
        Console.WriteLine("   CounterFrequency = " + s.CounterFrequency);
        Console.WriteLine("   CounterTimeStamp = " + s.CounterTimeStamp);
        Console.WriteLine("   CounterType      = " + s.CounterType);
        Console.WriteLine("   RawValue         = " + s.RawValue);
        Console.WriteLine("   SystemFrequency  = " + s.SystemFrequency);
        Console.WriteLine("   TimeStamp        = " + s.TimeStamp);
        Console.WriteLine("   TimeStamp100nSec = " + s.TimeStamp100nSec);
        Console.WriteLine("++++++++++++++++++++++");
    }
}

Imports System
Imports System.Collections
Imports System.Collections.Specialized
Imports System.Diagnostics
Imports System.Runtime.InteropServices
Imports Microsoft.VisualBasic

Public Class App

    Public Shared Sub Main()
        CollectSamples()
    End Sub

    Private Shared Sub CollectSamples()

        Dim categoryName As String = "ElapsedTimeSampleCategory"
        Dim counterName As String = "ElapsedTimeSample"

        If Not PerformanceCounterCategory.Exists(categoryName) Then

            Dim CCDC As New CounterCreationDataCollection()

            ' Add the counter.
            Dim ETimeData As New CounterCreationData()
            ETimeData.CounterType = PerformanceCounterType.ElapsedTime
            ETimeData.CounterName = counterName
            CCDC.Add(ETimeData)

            ' Create the category.
            PerformanceCounterCategory.Create(categoryName, _
               "Demonstrates ElapsedTime performance counter usage.", _
                   PerformanceCounterCategoryType.SingleInstance, CCDC)

        Else
            Console.WriteLine("Category exists - {0}", categoryName)
        End If

        ' Create the counter.
        Dim PC As PerformanceCounter
        PC = New PerformanceCounter(categoryName, counterName, False)

        ' Initialize the counter.
        PC.RawValue = Stopwatch.GetTimestamp()

        Dim Start As DateTime = DateTime.Now

        ' Loop for the samples.
        Dim j As Integer
        For j = 0 To 99
            ' Output the values.
            If j Mod 10 = 9 Then
                Console.WriteLine(("NextValue() = " _
                    + PC.NextValue().ToString()))
                Console.WriteLine(("Actual elapsed time = " _
                    + DateTime.Now.Subtract(Start).ToString()))
                OutputSample(PC.NextSample())
            End If

            ' Reset the counter every 20th iteration.
            If j Mod 20 = 0 Then
                PC.RawValue = Stopwatch.GetTimestamp()
                Start = DateTime.Now
            End If
            System.Threading.Thread.Sleep(50)
        Next j

        Console.WriteLine(("Elapsed time = " + _
              DateTime.Now.Subtract(Start).ToString()))
    End Sub


    Private Shared Sub OutputSample(ByVal s As CounterSample)
        Console.WriteLine(ControlChars.Lf + ControlChars.Cr + "+++++++")

        Console.WriteLine("Sample values - " + ControlChars.Cr _
              + ControlChars.Lf)
        Console.WriteLine(("   BaseValue        = " _
              + s.BaseValue.ToString()))
        Console.WriteLine(("   CounterFrequency = " + _
              s.CounterFrequency.ToString()))
        Console.WriteLine(("   CounterTimeStamp = " + _
              s.CounterTimeStamp.ToString()))
        Console.WriteLine(("   CounterType      = " + _
              s.CounterType.ToString()))
        Console.WriteLine(("   RawValue         = " + _
              s.RawValue.ToString()))
        Console.WriteLine(("   SystemFrequency  = " + _
              s.SystemFrequency.ToString()))
        Console.WriteLine(("   TimeStamp        = " + _
              s.TimeStamp.ToString()))
        Console.WriteLine(("   TimeStamp100nSec = " + _
              s.TimeStamp100nSec.ToString()))

        Console.WriteLine("+++++++")
    End Sub
End Class

설명

참고

카운터의 계산 된 값을 두 개의 카운터 읽기에 종속 하는 경우 첫 번째 읽기 작업이 0.0을 반환 합니다.If the calculated value of a counter depends on two counter reads, the first read operation returns 0.0. 새 성능 카운터를 만드는 것과 같습니다는 다른 카운터를 지정 하려면 성능 카운터 속성 다시 설정 하 고 새 속성을 사용 하 여 첫 번째 읽기 작업이 0.0를 반환 합니다.Resetting the performance counter properties to specify a different counter is equivalent to creating a new performance counter, and the first read operation using the new properties returns 0.0. 권장 되는 지연 시간에 대 한 호출 사이 NextValue 메서드 1 초 이며, 다음 증분 읽기를 수행 하는 카운터 수 있도록 합니다.The recommended delay time between calls to the NextValue method is one second, to allow the counter to perform the next incremental read.

참고

성능 카운터를 읽으려면 관리자 권한이 있어야 합니다.To read performance counters, you must have administrative privileges. Windows Vista에서는 UAC(사용자 계정 컨트롤)가 사용자 권한을 결정합니다.In Windows Vista, User Account Control (UAC) determines the privileges of a user. 기본 제공 Administrators 그룹의 멤버인 경우 두 개의 런타임 액세스 토큰(표준 사용자 액세스 토큰 및 관리자 액세스 토큰)이 할당됩니다.If you are a member of the Built-in Administrators group, you are assigned two run-time access tokens: a standard user access token and an administrator access token. 기본적으로 표준 사용자 역할이 지정됩니다.By default, you are in the standard user role. 성능 카운터에 액세스 하는 코드를 실행 하려면 먼저 높여야 권한을 표준 사용자에서 관리자에 게 합니다.To execute the code that accesses performance counters, you must first elevate your privileges from standard user to administrator. 애플리케이션 아이콘을 마우스 오른쪽 단추로 클릭하고 관리자로 실행하도록 지정하여 애플리케이션을 시작하면 이 작업을 수행할 수 있습니다.You can do this when you start an application by right-clicking the application icon and indicating that you want to run as an administrator.

보안

PerformanceCounterPermission
성능 카운터 범주를 읽는 합니다.for reading the performance counter category. 연관된 열거형: ReadAssociated enumeration: Read.

적용 대상