This documentation is archived and is not being maintained.

EventLog Constructor (String, String, String)

.NET Framework 1.1

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.

[Visual Basic]
Public Sub New( _
   ByVal logName As String, _
   ByVal machineName As String, _
   ByVal source As String _
public EventLog(
   string logName,
 string machineName,
 string source
public: EventLog(
   String* logName,
 String* machineName,
 String* source
public function EventLog(
   logName : String,
 machineName : String,
 source : String


The name of the log on the specified computer
The computer on which the log exists.
The source of event log entries.


Exception Type Condition
ArgumentException The log name is invalid.


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.


[Visual Basic, C#, C++] The following example writes an entry to an event log, "MyNewLog", on the local computer, using the source "MySource".

[Visual Basic, C#, C++] Note   If "MySource" does not already exist, the WriteEntry method creates it before writing to the event log.
[Visual Basic] 
Option Strict
Option Explicit

Imports System
Imports System.Diagnostics
Imports System.Threading

Class MySample
    Public Shared Sub Main()
        ' 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

using System;
using System.Diagnostics;
using System.Threading;
class MySample{

    public static void Main(){
        // Create an EventLog instance and assign its source.
        EventLog myLog = new EventLog("myNewLog", ".", "MySource");

        // Write an entry to the log.        
        myLog.WriteEntry("Writing to event log on " + myLog.MachineName);


#using <mscorlib.dll>
#using <System.dll>
using namespace System;
using namespace System::Diagnostics;
using namespace System::Threading;

int main(){

    // Create an EventLog instance and assign its source.
    EventLog* myLog = new EventLog(S"myNewLog", S".", S"MySource");

    // Write an entry to the log.        
    myLog->WriteEntry(String::Format( S"Writing to event log on {0}", myLog->MachineName ));


[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.


Platforms: Windows NT Server 4.0, Windows NT Workstation 4.0, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

.NET Framework Security: 

See Also

EventLog Class | EventLog Members | System.Diagnostics Namespace | EventLog Constructor Overload List | Source | Log | MachineName | Entries | WriteEntry | EventLogEntry