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EventLog Constructor (String, String, String)

Initializes a new instance of the EventLog class. Associates the instance with a log on the specified computer and creates or assigns the specified source to the EventLog.

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

'Declaration
Public Sub New ( _
	logName As String, _
	machineName As String, _
	source As String _
)

Parameters

logName
Type: System.String

The name of the log on the specified computer

machineName
Type: System.String

The computer on which the log exists.

source
Type: System.String

The source of event log entries.

ExceptionCondition
ArgumentNullException

The log name is Nothing.

ArgumentException

The log name is invalid.

-or-

The computer name is invalid.

This constructor sets the Log property to the logName parameter, the MachineName property to the machineName parameter, and the Source property to the source parameter. The Source property is required when writing to an event log. However, if you are only reading from an event log, only the Log and MachineName properties are required (as long as the event log on the server has a source already associated with it). If you are only reading from the event log, another overload of the constructor might suffice.

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

Property

Initial Value

Source

The source parameter.

Log

The logName parameter.

MachineName

The machineName parameter.

The following example writes an entry to an event log, "MyNewLog", on the local computer, using the source "MySource".

Option Strict
Option Explicit

Imports System
Imports System.Diagnostics
Imports System.Threading

Class MySample
    Public Shared Sub Main()
        If Not EventLog.SourceExists("MySource") Then 
            ' Create the source, if it does not already exist. 
            ' 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("CreatingEventSource")
            'The source is created.  Exit the application to allow it to be registered. 
            Return 
        End If 
        ' Create an EventLog instance and assign its source. 
        Dim myLog As New EventLog("myNewLog", ".", "MySource")

        ' Write an entry to the log.        
        myLog.WriteEntry(("Writing to event log on " & myLog.MachineName))
    End Sub ' Main 
End Class ' MySample

.NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

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

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