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PerformanceCounter.NextSample Method

Obtains a counter sample, and returns the raw, or uncalculated, value for it.

Namespace: System.Diagnostics
Assembly: System (in system.dll)

public CounterSample NextSample ()
public CounterSample NextSample ()
public function NextSample () : CounterSample

Return Value

A CounterSample that represents the next raw value that the system obtains for this counter.

Exception typeCondition

InvalidOperationException

The instance is not correctly associated with a performance counter.

-or-

The InstanceLifetime property is set to Process when using global shared memory.

Win32Exception

An error occurred when accessing a system API.

PlatformNotSupportedException

The platform is Windows 98 or Windows Millennium Edition (Me), which does not support performance counters.

This method is generally used for counters that contain uncalculated values.

NoteNote

If the value for the InstanceLifetime property is Process and the performance counter category was created with .NET Framework version 1.0 or 1.1, an InvalidOperationException is thrown. Performance counter categories created with earlier versions use global shared memory, and the value for InstanceLifetime must be Global. If the category is not used by applications running on versions 1.0 or 1.1 of the .NET Framework, delete and recreate the category.


using System;
using System.Collections;
using System.Collections.Specialized;
using System.Diagnostics;

public class App {

	private static PerformanceCounter PC;
	private static PerformanceCounter BPC;

	public static void Main()
	{	
	
		ArrayList samplesList = new ArrayList();

		SetupCategory();
		CreateCounters();
		CollectSamples(samplesList);
		CalculateResults(samplesList);

	}
	

	private static bool SetupCategory()
	{		
		if ( !PerformanceCounterCategory.Exists("AverageCounter64SampleCategory") ) 
		{

			CounterCreationDataCollection CCDC = new CounterCreationDataCollection();
			
			// Add the counter.
			CounterCreationData averageCount64 = new CounterCreationData();
			averageCount64.CounterType = PerformanceCounterType.AverageCount64;
			averageCount64.CounterName = "AverageCounter64Sample";
			CCDC.Add(averageCount64);
	        
	        // Add the base counter.
			CounterCreationData averageCount64Base = new CounterCreationData();
			averageCount64Base.CounterType = PerformanceCounterType.AverageBase;
			averageCount64Base.CounterName = "AverageCounter64SampleBase";
			CCDC.Add(averageCount64Base);

			// Create the category.
			PerformanceCounterCategory.Create("AverageCounter64SampleCategory", 
				"Demonstrates usage of the AverageCounter64 performance counter type.", 
				CCDC);
				
			return(true);
		}
		else
		{
			Console.WriteLine("Category exists - AverageCounter64SampleCategory");
			return(false);
		}
	}
	
	private static void CreateCounters()
	{
		// Create the counters.

		PC = new PerformanceCounter("AverageCounter64SampleCategory", 
			"AverageCounter64Sample", 
			false);
		

		BPC = new PerformanceCounter("AverageCounter64SampleCategory", 
			"AverageCounter64SampleBase", 
			false);
		
		
		PC.RawValue=0;
		BPC.RawValue=0;
	}
	
	private static void CollectSamples(ArrayList samplesList)
	{
		
		Random r = new Random( DateTime.Now.Millisecond );

		// Loop for the samples.
		for (int j = 0; j < 100; j++) 
		{
	        
			int value = r.Next(1, 10);
			Console.Write(j + " = " + value);

			PC.IncrementBy(value);

			BPC.Increment();

			if ((j % 10) == 9) 
			{
				OutputSample(PC.NextSample());
				samplesList.Add( PC.NextSample() );
			}
			else
				Console.WriteLine();
	        
			System.Threading.Thread.Sleep(50);
		}

	}
	
	private static void CalculateResults(ArrayList samplesList)
	{
		for(int i = 0; i < (samplesList.Count - 1); i++)
		{
			// Output the sample.
			OutputSample( (CounterSample)samplesList[i] );
			OutputSample( (CounterSample)samplesList[i+1] );

			// Use .NET to calculate the counter value.
			Console.WriteLine(".NET computed counter value = " +
				CounterSampleCalculator.ComputeCounterValue((CounterSample)samplesList[i],
				(CounterSample)samplesList[i+1]) );

			// Calculate the counter value manually.
			Console.WriteLine("My computed counter value = " + 
				MyComputeCounterValue((CounterSample)samplesList[i],
				(CounterSample)samplesList[i+1]) );

		}
	}
	
	
	//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++
	//	Description - This counter type shows how many items are processed, on average,
	//		during an operation. Counters of this type display a ratio of the items 
	//		processed (such as bytes sent) to the number of operations completed. The  
	//		ratio is calculated by comparing the number of items processed during the 
	//		last interval to the number of operations completed during the last interval. 
	// Generic type - Average
	//  	Formula - (N1 - N0) / (D1 - D0), where the numerator (N) represents the number 
	//		of items processed during the last sample interval and the denominator (D) 
	//		represents the number of operations completed during the last two sample 
	//		intervals. 
	//	Average (Nx - N0) / (Dx - D0)  
	//	Example PhysicalDisk\ Avg. Disk Bytes/Transfer 
	//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++
	private static Single MyComputeCounterValue(CounterSample s0, CounterSample s1)
	{
		Single numerator = (Single)s1.RawValue - (Single)s0.RawValue;
		Single denomenator = (Single)s1.BaseValue - (Single)s0.BaseValue;
		Single counterValue = numerator / denomenator;
		return(counterValue);
	}
		
	// Output information about the counter sample.
	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("++++++++++++++++++++++");
	}
}

import System.*;  
import System.Collections.*;  
import System.Collections.Specialized.*;  
import System.Diagnostics.*;  

public class App
{
    private static PerformanceCounter pc;
    private static PerformanceCounter bpc;

    public static void main(String[] args)
    {
        ArrayList samplesList = new ArrayList();
        SetupCategory();
        CreateCounters();
        CollectSamples(samplesList);
        CalculateResults(samplesList);
    } //main

    private static boolean SetupCategory()
    {
        if (!(PerformanceCounterCategory.Exists(
            "AverageCounter64SampleCategory"))) {
            CounterCreationDataCollection ccdc = 
                new CounterCreationDataCollection();
            // Add the counter.
            CounterCreationData averageCount64 = new CounterCreationData();
            averageCount64.
                set_CounterType(PerformanceCounterType.AverageCount64);
            averageCount64.set_CounterName("AverageCounter64Sample");
            ccdc.Add(averageCount64);
            // Add the base counter.
            CounterCreationData averageCount64Base = new CounterCreationData();
            averageCount64Base.set_CounterType(PerformanceCounterType.
                AverageBase);
            averageCount64Base.set_CounterName("AverageCounter64SampleBase");
            ccdc.Add(averageCount64Base);
            // Create the category.
            PerformanceCounterCategory.Create("AverageCounter64SampleCategory",
                "Demonstrates usage of the AverageCounter64 performance "
                + "counter type.", ccdc);
            return true;
        }
        else {
            Console.WriteLine("Category exists - AverageCounter64SampleCategory");
            return false;
        }
    } //SetupCategory

    private static void CreateCounters()
    {
        // Create the counters.
        pc = new PerformanceCounter("AverageCounter64SampleCategory",
            "AverageCounter64Sample", false);
        bpc = new PerformanceCounter("AverageCounter64SampleCategory",
            "AverageCounter64SampleBase", false);
        pc.set_RawValue(0);
        bpc.set_RawValue(0);
    } //CreateCounters

    private static void CollectSamples(ArrayList samplesList)
    {
        Random r = new Random(DateTime.get_Now().get_Millisecond());
        // Loop for the samples.
        for (int j = 0; j < 100; j++) {
            int value = r.Next(1, 10);
            Console.Write(j + " = " + value);
            pc.IncrementBy(value);
            bpc.Increment();

            if (j % 10 == 9) {
                OutputSample(pc.NextSample());
                samplesList.Add(pc.NextSample());
            }
            else {
                Console.WriteLine();
            }
            System.Threading.Thread.Sleep(50);
        }
    } //CollectSamples

    private static void CalculateResults(ArrayList samplesList)
    {
        for (int i = 0; i < samplesList.get_Count() - 1; i++) {
            // Output the sample.
            OutputSample((CounterSample)samplesList.get_Item(i));
            OutputSample((CounterSample)samplesList.get_Item(i + 1));
            // Use.NET to calculate the counter value.
            Console.WriteLine(".NET computed counter value = " 
                + CounterSampleCalculator.ComputeCounterValue((CounterSample)
                samplesList.get_Item(i), 
                (CounterSample)samplesList.get_Item(i + 1)));
            // Calculate the counter value manually.
            Console.WriteLine("My computed counter value = "
                + MyComputeCounterValue((CounterSample)samplesList.get_Item(i),
                (CounterSample)samplesList.get_Item(i + 1)));
        }
    } //CalculateResults

    //++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++
    //++++++++
    //    Description - This counter type shows how many items are processed, 
    //        on average,during an operation.Counters of this type display a
    //        ratio of the items processed (such as bytes sent) to the number
    //        of operations completed. The ratio is calculated by comparing
    //        the number of items processed during the last interval to the 
    //        number of operations completed during the last interval. 
    //  Generic type - Average
    //        Formula - (N1 - N0) / (D1 - D0), where the numerator (N) 
    //        represents the number of items processed during the last sample
    //        interval and the denominator (D) represents the number of
    //        operations completed during the last two sample 
    //        intervals. 
    //    Average (Nx - N0) / (Dx - D0)  
    //    Example PhysicalDisk\ Avg. Disk Bytes/Transfer 
    //++++++++//++++++++//++++++++//++++++++//++++++++//++++++++//++++++++
    //++++++++
    private static float MyComputeCounterValue(CounterSample s0,
        CounterSample s1)
    {
        float numerator = (float)s1.get_RawValue() - (float)s0.get_RawValue();
        float denomenator = (float)s1.get_BaseValue() - (float)s0.
            get_BaseValue();
        float counterValue = numerator / denomenator;
        return counterValue;
    } //MyComputeCounterValue

    // Output information about the counter sample.
    private static void OutputSample(CounterSample s)
    {
        Console.WriteLine("\r\n+++++++++++");
        Console.WriteLine("Sample values - \r\n");
        Console.WriteLine("   BaseValue        = " + s.get_BaseValue());
        Console.WriteLine("   CounterFrequency = " + s.get_CounterFrequency());
        Console.WriteLine("   CounterTimeStamp = " + s.get_CounterTimeStamp());
        Console.WriteLine("   CounterType      = " + s.get_CounterType());
        Console.WriteLine("   RawValue         = " + s.get_RawValue());
        Console.WriteLine("   SystemFrequency  = " + s.get_SystemFrequency());
        Console.WriteLine("   TimeStamp        = " + s.get_TimeStamp());
        Console.WriteLine("   TimeStamp100nSec = " + s.get_TimeStamp100nSec());
        Console.WriteLine("++++++++++++++++++++++");
    } //OutputSample
} //App

Windows 98, Windows 2000 SP4, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0
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