EventLog Constructor (String)

EventLog Constructor (String)

Initializes a new instance of the EventLog class. Associates the instance with a log on the local computer.

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

public EventLog(
	string logName


Type: System.String

The name of the log on the local computer.


The log name is null.


The log name is invalid.

This overload sets the Log property to the logName parameter. Before calling WriteEntry, specify the Source property of the EventLog instance. If you are only reading Entries from the log, you can alternatively specify only the Log and MachineName properties.


If you do not specify a MachineName, the local computer (".") is assumed. This overload of the constructor specifies the Log property, but you can change this before reading the Entries property.

If the source you specify in the Source property is unique from other sources on the computer, a subsequent call to WriteEntry creates a log with the specified name, if it does not already exist.

The following table shows initial property values for an instance of EventLog.


Initial Value


An empty string ("").


The logName parameter.


The local computer (".").

The following example reads entries in the event log, "myNewLog", on the local computer.

using System;
using System.Diagnostics;
using System.Threading;

class MySample

    public static void Main()
        // Create the source, if it does not already exist. 
        if (!EventLog.SourceExists("MySource"))
            //An event log source should not be created and immediately used. 
            //There is a latency time to enable the source, it should be created 
            //prior to executing the application that uses the source. 
            //Execute this sample a second time to use the new source.
            EventLog.CreateEventSource("MySource", "MyNewLog");
            Console.WriteLine("Exiting, execute the application a second time to use the source.");
            // The source is created.  Exit the application to allow it to be registered. 

        // Create an EventLog instance and assign its log name.
        EventLog myLog = new EventLog("myNewLog");

        // Read the event log entries. 
        foreach (EventLogEntry entry in myLog.Entries)
            Console.WriteLine("\tEntry: " + entry.Message);

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

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