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PerformanceCounter Constructor (String, String, String, String)

Initializes a new, read-only instance of the PerformanceCounter class and associates it with the specified system or custom performance counter and category instance, on the specified computer.

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

public PerformanceCounter (
	string categoryName,
	string counterName,
	string instanceName,
	string machineName
public PerformanceCounter (
	String categoryName, 
	String counterName, 
	String instanceName, 
	String machineName
public function PerformanceCounter (
	categoryName : String, 
	counterName : String, 
	instanceName : String, 
	machineName : String



The name of the performance counter category (performance object) with which this performance counter is associated.


The name of the performance counter.


The name of the performance counter category instance, or an empty string (""), if the category contains a single instance.


The computer on which the performance counter and its associated category exist.

Exception typeCondition


The categoryName is an empty string ("").


The counterName is an empty string ("").


The read/write permission setting requested is invalid for this counter.


The counter does not exist on the specified computer.


The category specified is marked as multi-instance and requires the performance counter to be created with an instance name.


The instanceName is longer than 127 characters.


The machineName parameter is not valid.


The categoryName or counterName parameter is a null reference (Nothing in Visual Basic).


An error occurred when accessing a system API.


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

The parameter strings are not case sensitive.

This overload of the constructor sets the CategoryName, CounterName, InstanceName, and MachineName properties to the values you pass in.

This constructor initializes the performance counter and associates the instance with an existing counter (either a system or a custom counter) on the specified computer. The values that you pass in for the CategoryName, CounterName, InstanceName and MachineName properties must point to an existing performance counter. If the performance counter instance you point to is not valid, calling the constructor throws an exception. This overload can access any read-only or read/write counter, but does so in a read-only mode. A PerformanceCounter instance created using this overload cannot write to the counter, even if the counter itself is read/write.


You cannot write to remote performance counters. There is no overload that allows you to specify a read/write instance of the PerformanceCounter class that connects to a remote computer.

To create a performance category instance, specify an instanceName on the PerformanceCounter constructor. If the category instance specified by instanceName already exists the new object will reference the existing category instance.

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